Soft Left Rear Spring Dirt Late Model | Quick Tips About 100 Lbs Left Rear Spring 상위 80개 답변

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soft left rear spring dirt late model 주제에 대한 동영상 보기

여기에서 이 주제에 대한 비디오를 시청하십시오. 주의 깊게 살펴보고 읽고 있는 내용에 대한 피드백을 제공하세요!

d여기에서 Quick Tips About 100 LBS Left Rear Spring – soft left rear spring dirt late model 주제에 대한 세부정보를 참조하세요

This is a quick sneak peak of our 2-Link Chassis Schools. Bob and the guys talk a little about the trend of going with a very light left rear spring and loading it up. The pros and cons of doing so are also mentioned in this video briefly.
Full video link:

soft left rear spring dirt late model 주제에 대한 자세한 내용은 여기를 참조하세요.

Dirt Late Model Newsletter – Advanced Racing Suspensions

The 4” top (extended load) spring on the left rear preloader has been changed to a 4” x 050 lbs. spring. Softening this spring has created more traction on …

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Date Published: 1/19/2021

View: 4516

LR spring theory… [Archive] – – The Most Opinionated … – The Most Opinionated Racing Message Board In The Universe > Racing Tech > Dirt Late Models > LR spring theory… PDA. View Full Version : LR spring …

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Date Published: 12/5/2022

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Why Dirt Racers are Stacking Springs – It’s Worn

… and left rear corners on many Dirt Late Models in today’s racing. … the Dirt Late Models, allowed the car to run on a very soft spring …

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Date Published: 10/4/2021

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Spring Rate – Crutches Revisited – Part Two Of A … – MotorTrend

For big bar and soft spring setups on asphalt, the right-rear spring … Dirt Late Model teams are running much stiffer right-rear springs …

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Date Published: 12/23/2021

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adjustment guide – to tighten car on entry – » PPM Racing

Decrease Compression Right Rear Shock. Increase Rebound 5th Coil … Stiffen Left Front Spring 25# at a Time … Increase Gas Pressure Left Rear Front Shock.

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Date Published: 6/10/2022

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주제와 관련된 더 많은 사진을 참조하십시오 Quick Tips About 100 LBS Left Rear Spring. 댓글에서 더 많은 관련 이미지를 보거나 필요한 경우 더 많은 관련 기사를 볼 수 있습니다.

Quick Tips About 100 LBS Left Rear Spring
Quick Tips About 100 LBS Left Rear Spring

주제에 대한 기사 평가 soft left rear spring dirt late model

  • Author: Race Tech Info
  • Views: 조회수 37,996회
  • Likes: 좋아요 244개
  • Date Published: 2021. 4. 16.
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What is Droop late model?

The ‘Droop Rule’, which is employed by both national series as well as many regional tours, calls for that measurement from the rear deck to the ground to be 50 inches. The Lucas Oil Late Model Dirt Series allows for a one-inch tolerance to account for unlevel ground on which the measurement might be taken.

How do you increase side bites in a dirt track car?

To give the car more lateral traction, go to a softer right rear bar or a stiffer right front spring. A stiffer left rear bar will have two effects: raising the car (higher CGH), and adding static left rear weight.

How do I get more rear traction?

The correct tires and less horsepower is your main problem. Also try changing your anti-squat (C plate) to 2 dot up. It will allow the rear tire to dig in under acceleration and get you to square up more. A couple things I would try would be to run a softer rear sway bar and also to use the upper hole in the rear hubs.

What is wedge in a dirt late model?

The tire at the rear on the left loses the greatest amount of weight, and the difference in its weight compared to the right-hand rear tire is known as the wedge. If the wedge is too high, then that means the left-hand rear tire is too heavy, and the car will not handle well as it’s steered through the corner.

What is the Lucas Oil droop rule?

Rear travel limiter: Commonly known as the “droop” rule, postrace rear deck height must not exceed 51 inches (checked with both rear tires off the ground). Failing inspection results in disqualification that disallows a driver’s time trials or puts the driver to the rear of the previous race’s finishing order.

What does a droop limiter do?

Droop is usually changed via internal shock limiters or on some cars via specific droop/downtravel/downstop limiters. Droop allows or limits the weight transfer from one side of the car to the other.

How is left rear bite calculated?

Subtracting the amount of weight supported by the RR tire from the LR tire’s weight, we arrive at a number and call that the amount of bite in the car, i.e., “100 pounds of bite or left rear.”

What is forward bite?

Foward bit is straight line traction (think dragrace). Side bite keeps tires from sliding sideways in a corner. The front can push and you will not turn very well. If the rear slides you can end up spinning around.

What is droop in dirt track racing?

Rear travel limiter: Colloquially known as the “droop” rule, postrace rear deck height must not exceed 51 inches (checked with both rear tires off the ground). Failing inspection results in disqualification that disallows a driver’s time trials or puts the driver to the rear of the previous race’s finishing order.

Dirt Late Model Spring Stacking BS, What is the Point?

Now we are knee deep in this crap of spring stacking. Years ago we stacked springs and everyone thought it was stupid. Now, it seems everyone thinks you’re stupid if you’re not stacking and smashing springs.

So, let’s discuss the whole spring stacking thing a little further by first answering the question.

Is spring stacking necessary?


In many situations, you can still be just as fast as the guys stacking springs. And in some instances, you will be faster.

It really depends on how you drive, track conditions and the level of competition you are running against.

Certain places where no one has started stacking springs, the driving style at the track may put you behind if you do. The way a majority of the cars at the track run will often determine the shape of the track.

It seems to me when guys start all doing the same thing at a track, the track will change. It’s not all how people prepare the track. Most times it’s more about how the track gets worn in as the night goes on.

What is spring stacking good for then?

Spring stacking is used for different things on different corners of the car. Learn to use it as a tool to achieve what you want. Don’t feel you have to do what everyone else is doing, just because they are doing it.

Please don’t fall into that ‘monkey see monkey do’ crap trap.

But, I realize that in order to use it as a tool, you need to understand what it does and how to tune it for each corner of the car.

So, I’m going to break down what it does at the two most important spring stacking corners of the car so you can use it as a tool.

Spring Stacking on a Late Model Right Front.

The spring stacking on the right front is done to get the car, and keep the car, at a particular ride height all the way around the track.

There are a couple of things going on here. First, having a very soft spring on the right front will get the car to your race ride height faster.

Just put a soft spring up there.

The problem is if you just put a soft spring on the right front then you get the car to a workable dynamic ride height, the spring will be too soft to support the car if it hits any bumps or the track conditions change as the race progresses.

You stack springs to get the car quickly onto the right front. Then you need to either put a bump stop set-up on there to keep the front end down, or you need to lock out one of the springs so the car can see small changes in load without bottoming out or popping up too quickly.

Too much rebound on the right front.

Relying on a big rebound shock to keep the car on the right front is a crutch. The ideal scenario is to have the car stay there naturally and only put enough shock rebound there to add traction. Most of the cars running today probably have too much rebound and need to reconsider their right front spring set up.

The front end is too low because everything drags.

There is a common misconception, that if the front end drags, all the stuff needs to be raised to allow more clearance.

Not true!

There is a certain ride height the car is meant to run at. The upper and lower intersection points create an instant center. This instant center can act much like a panhard bar would in the front.

So, there is a certain height the front end needs to run at to create the most traction. The solution if your car is bottoming out is not always to make more clearance. Sometimes you just need to stick some shims in the shock to raise the ride height.

I see too many people running around screaming because their car is bottoming out. I could probably fix so many handling problems by just walking around with a pocket full of shims for the right front shock.

This is also the best way to add some traction as the track starts slicking off. Adding shim will very often add some traction by putting some tension between the left rear and the right front. This can also tighten the car up from center off if the car is too loose.

What does stacking springs on the left rear

Left rear spring stacking is a little different than the right front. We stack springs on the left rear to get more instant traction and hold traction in the car.

The softer the left rear spring, the more preload has to go into the spring to hold the car at ride height. The stacking of springs allows you to get a very soft rate and enough height to maintain a preload as the left rear of the car raises. I’ve seen and experimented with a ton of combinations over the years, but it seems a pair of 200 lb. springs seem to be a pretty safe place to start. I think these usually were around a 12” and a 4” springs. This will give you a 100 lb/in spring rate.

I’ve seen spring rates as low as 75 to 80 lbs./in.

I think what you are looking for is to have some preload on the spring when the left rear is at full droop before it drives back into the hook. This will maintain flex in the tire which is where your traction comes from.

This spring support pushing down on the hook of the back side of the birdcage allows the top rod to move in and out of the hook and allow the tire flex.

I whipped up a diagram to illustrate this a little better.

The top arm is cushioned by the movement of the rear sprint as it moves in and out of the hook.

Some may be wondering what I consider the hook.

As your birdcage drops the left rear back shock mount will drop slightly as the birdcage moves forward. Not nearly as much as the front just because of the rotation of the birdcage because of the angle of the rods.

There will come a point where the spring stops extending and starts compressing. This is the bottom of the hook. If you plot the axle drop on a graph every ½”, you’ll notice at some point the graph will begin to look like a hook. The distance between the bottom of the hook and the cam over point on your top rod will be the amount of cushion the tire will see.

Like I said above I like to see about 25 to 50 lbs. of preload at this cam over point. The preload will increase the further the spring is pushed into the hook and the overall spring rate of the stack.

Let’s wrap this up so we can get looking at this on our own cars and spring smashers.

Just remember with all this spring stacking and wheel load crap happening now:

This stuff isn’t new, it’s been happening for a while. The key to going fast with it is understanding exactly how it works and how you can use it as a tool. Single spring stuff can still go fast.

Next time we’ll go a little deeper and maybe get into the right rear spring stacking possibilities.

Till next time, be safe.


Overton owns up to Thursday night Droop Rule miscalculation – Inside Dirt Racing

One of the easiest reactions to have in sports when things don’t go your way is to blame the rules and the officials who enforce those rules. “The NFL overtime rule is stupid”; “The umpire’s strike zone was too narrow”; “The ref missed a critical block/charge call” are all commonly heard statements following a loss. And depending on the allegiances of fans, some will agree with those assessments and others will call the complainer a cry baby.

However, Brandon Overton chose to go a different route after a rule enforcement went against him and his Wells Motorsports team on Thursday night. Rather than blame the new ‘Droop Rule’ or curse Lucas Oil Late Model Dirt Series officials, the 30-year-old driver opted to accept responsibility and place the blame squarely on himself.

After qualifying for the opening night of the ‘Super Clean Super Bowl of Racing’ at the Golden Isles Speedway in Brunswick, Georgia, Overton’s No. 76 Longhorn Chassis was found to be in violation of a rule being enforced for the first time by the Lucas Oil Late Model Dirt Series. The regulation is meant to limit the amount of vertical travel in the left rear of the car. To check that, series tech director Steve Francis jacks the car up at the rear until the left rear tire is off the ground then he measures the height from the rear deck of the car to the ground.

The ‘Droop Rule’, which is employed by both national series as well as many regional tours, calls for that measurement from the rear deck to the ground to be 50 inches. The Lucas Oil Late Model Dirt Series allows for a one-inch tolerance to account for unlevel ground on which the measurement might be taken.

Overton had just posted the fastest time in Group A qualifying on Thursday night but that effort was disallowed when his car did not meet the specified tolerance. As a result, the driver who was the talk of the Dirt Late Model world in 2021 had to start his heat race from the tail. “Big Sexy” was unable to race his way into the feature via his heat race or his B-main which left him on the sidelines for the $10,000-to-win main event.

After earning a redemptive win on Friday night at Golden Isles, Overton reflected on the previous evening.

“It is what it is,” Overton told as his car was going through post-race technical inspection. “You know, it sucks. Redemption? Yeah, that’s cool. We came back. My guys work so hard on this thing and I kind of screwed them last night.”

Overton was congratulatory of Thursday night victor Devin Moran as he reflected back on the events that led to his qualifying time being negated.

“I’m not saying we would have won because Devin was really good and if anybody else is going to win, I’m glad it was him,” the Evans, Georgia driver declared. “But I didn’t even give them(his crew) a chance to win. That was my fault. I just missed it.”

The droop rule was initially put in use in 2018 by the Ray Cook-promoted Schaeffer’s Oil family of series. While the Lucas Oil tour isn’t checking each car’s droop in exactly the same way as Cook, Overton says he had initially accounted for the difference. He just got caught up in trying to get other aspects of his car right.

“I’ve raced a million Ray Cook races when the droop rule was in effect and they(LOLMDS) are doing it a little different than we’ve always done it and I adjusted for it before we came here,” Overton explained. “I got in the zone of trying to get all my shocks and springs set up and I just swapped and forgot that I didn’t have that one set. I didn’t know until after I qualified.”

Ultimately, Overton says he and his crew took it in stride and moved on.

“It’s racing, man. S**t happens and we’ll just carry on. Nobody threw a hissy fit or got pouty about it and that’s why I love all these guys that help me.”

That’s not a reaction we are used to hearing from athletes in other sports.

Respond to this post on Twitter by following @RichardAllenIDR and @MichaelRMoats or by liking the Facebook page.

Also, NASCAR and pavement racing fans can check out InsideCircleTrack.

Rethink Dirt: Advanced Theory

why your car does what it does

This article has been re-written in November of 2014 to update the content. To save this document, print it out, or view it in a normal format, click on the link below. This is a long in-depth article. Take your time and understand.

Rethink Dirt: Advanced Dirt Track Theory

I have another article to go along with this one. Please read this article first then read Shocks: A Mystery No More.

My Big T.O.E. on Dirt

I have been a dirt track racer for life, attending races since I was 3. I am also a fan of theoretical physics. There are proven formulas for Newtonian physics (basic understanding of how things move) and there are formulas for quantum physics (how atoms and particles move). But the two fields of study have great contradictions among them, things seem to work differently on an atomic level than they do at our level. Ever since Albert Einstein’s theory of general relativity, physicist have been trying to tie the two fields together, to devise a theory that fully explains all known physical phenomena into a Theory Of Everything (T.O.E.). Einstein himself died trying to develop a big T.O.E. Theoretical physics is the field of cutting edge theory in this area. Dirt track racing needs a big T.O.E. A theory to explain why the adjustments we make on our race car have the effects they do. Although we may know how adjustments affect the car, we do not always know why the adjustments do what they do. We may think we know or we may develop some theory of why they do what they do, but do we really understand? It has been my life long search to understand all that I can about dirt track chassis setup. Not until after reading tons of books, talking to hundreds of racers, thinking obsessively about it, meditating on it, collecting/analyzing gobs of data, and racing for 34 years that I think I may have a big T.O.E for dirt track racing. Although I think I have it clear in my head, writing it down is another issue.

Side Bite? Fact or Fiction?

On asphalt, without wings, there are lots of books written based on the laws of physics, with skid pad tests to back them up. Dirt track racers have never paid attention to these formulas and principles because when you take a car that handles well on asphalt, it does not do very well on dirt. Many changes need to be made to get it to work to the best of its potential when sliding on dirt. It was discovered that the right side tires needed to be moved in and the center of gravity needed to be moved up. The idea of side bite, the tires digging into the dirt when sliding, then became someone’s reason of why these changes needed to be made. Makes sense and explains why the adjustments work.

To the typical dirt racer, side bite is the idea that the car is rolling to the right, forcing the tires to dig into the dirt providing more traction. Like a paddle in the water, the further you push the paddle down into the water, the more force you can put through the paddle to propel the boat.

However, the only time this understanding of side bite really applies is when the tire grooves (paddles) can work into the dirt (water), which is when the track is wet or slightly wet, in this condition traction is not a problem. Wouldn’t you agree? After warm ups, or maybe into the heat races, the tire’s grooves can no longer work into the dirt, at least not much because the dirt is harder than the rubber. So this idea of side bite and trying to make the grooves work into the dirt by applying more weight to the right rear for traction doesn’t make much sense.

I have proven this to myself in years past by loading the right rear tire more and more trying to achieve more traction. While at times it would work, many times it did not. I could not put my finger on why this was the case.


Please keep in mind that these are not my ideas. The ideas I am about to show you have been proven and is documented in many books. In physics there is a whole branch of study called vehicle dynamics, which is where all the language and facts come from. The automotive industry has invested billions of dollars and time to document, research and test. Again, all of the study is on asphalt, not dirt, which is why it has gotten misrepresented and misapplied. Dirt is a whole lot more complicated and inconsistent than its prissy sister! But the laws of physics remain the same.

There are two basic formulas used in the vehicle dynamics world, one used for longitudinal weight transfer (front to back), and one used for lateral weight transfer (side to side). They look like this:

Lateral Weight Transfer = (Weight x CGH / TW) x G (lateral)

Longitudinal Weight Transfer = (Weight x CGH / WB) x G (longitudinal)

Where Center of Gravity Height=CGH, Tire offsets=Track Width or TW, Wheel Base=WB, G-force=G, and Weight of the Car =Weight

Don’t over complicate this. Just understand that to change the amount of weight transfer we need to change the CGH, change the tread width, or change the wheel base. The other variables are not relevant. We are also not going to slow down (decrease G’s). We are not going to add weight to the car, we need to keep the car light for acceleration. We do need to keep in mind that a heavier driver will very quickly change the way a car handles. He will change both the weight and the CGH.

I would like to change the term “side bite” to lateral traction. Lateral means side to side. I want to redefine the idea of side bite, lateral traction, and why dirt chassis need to be set up different than asphalt cars.

Forward bite is what dirt track racers use to describe available traction to propel the chassis forward. It makes sense, but in vehicle dynamics the term is longitudinal (front to back) traction.

These two formulas contain the only variables that affect weight transfer. Everything that you adjust on your car will change the way your car handles because it changed one of these variables or it change tire efficiency.

Tire Efficiency

So how do we achieve maximum traction? When we add weight to a tire the traction goes up, but not linearly (in a straight line). According to skid pad tests, it drops off pretty quick. Traction does not increase in proportion to the weight that is added.

As weight is added to the right rear tire, it will get more traction than it did with less weight on it. This much is true. But here is the catch, to gain that traction, weight had to come from somewhere. Some other tire needs to lose weight and therefore lose traction. Since we are only considering lateral weight transfer here, and we didn’t take the weight from the front tires, it had to come from the left rear tire. So now, by definition of the above graph, the left rear tire lost more traction than what the right rear gained.

Fundamental Truth #1:Maximum traction in the rear of the car is achieved when both rear tires have the same amount of weight on them, and as much as weight as possible is transferred to the rear.

Actually, due to the larger foot print or contact patch of the right rear tire, its efficiency curve is different than the left rear tire (it can handle more weight before the traction falls off), as a result, about 30% more right rear weight is needed to maximize the traction. Likewise, maximum traction in the front is achieved when the two front tires are equally loaded.

The weight on a race car is constantly shifting around, it is dynamic, it is not static (constant, still, not changing). We know that weight is going to transfer from the left to the right, then we can assume that we will need to start out with, in the static state, more weight on the left rear and less on the right than what we want to end up with in the middle of a turn. The question is how much.

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Maximum Traction Achieved

Now let’s go back and look at the formulas again, consider lateral traction first. How do we achieve maximum lateral traction?

Keep the CGH low. Although some of this is controlled by the design of the car, we can raise and lower the CGH. By lowering the car we transfer less weight and keep the rear tires more equally loaded providing more lateral traction.

Increase tire offset (TW) by offsetting the tires. Based on the formula, a bigger TW number will yield less weight transfer.

Make the car as light weight as possible. Less weight means less transfer.

We will talk about track width (tire offsets) later.

Our 600cc sprints will pull between 0.8 and 2.5 g’s in the middle of a turn depending on track conditions, size, and shape. A normally designed car will be transferring a total of 190 pounds on a slick track where the lateral g force is low and about 80 pounds of that is in the rear depending on roll couple (more on that in a minute) and many other factors. That means, in this example, we need to start out with 35 pounds heavy on the left rear to end up with 30% more right rear weight in the middle of the turn. (530lbs in the rear 283lbs LR/247lbs RR static, after weight transfer 203LR/327RR). You can calculate this stuff out. It is actually easy, until you add a wing on top of the car, more on that later.

Now let’s look at forward drive or longitudinal traction. Although tire efficiency does not increase as much as we add more weight, it still goes up. For more longitudinal traction, we need to increase weight transfer to the rear. How do we do that?

Raise the center of gravity height (CGH)

Shorten the wheel base (WB)

Increase the horse power

Yes, all that talk we just did above about lowering the CGH works great for lateral traction, but for longitudinal traction, or whenever we are spinning our wheels from lack of drive, the opposite is true. So that is why there has never been a clear advantage to raising or lowering your car, you will help one type of traction and hurt another.


Think about what you are adjusting and what you want to achieve. Think about the size of the track and/or the type of car to which we are applying these principles. A key concept is that if the horsepower is not high enough to break the tires loose in the forward direction, then the longitudinal traction is not an issue and we need to focus on lateral traction. If we can break the wheels loose anytime we want, then we need to focus on gaining longitudinal traction.

Due to gear ratio changes, a car is much more likely to spin tires due to lack of longitudinal traction on a small track than a large one. As far as micro sprints go, on tracks about 1/3 mile and bigger, longitudinal traction is generally not much of a problem. Track shape comes into play too as paper clip shaped tracks (tight turns long straights) tend to need more longitudinal traction than tracks that are more round shaped.

Sometimes you can look at the angle of the feathers on the tires and determine if you are spinning more in the longitudinal or lateral direction and make your adjustments accordingly.

Wheel Base

Some of you caught the part about wheel base. You get more weight transfer from the front to the rear with a shorter wheel base, but the disadvantage to a short wheel base is you lose rear weight percentage in the static state. A chassis with a long wheel base, at least if it is designed correctly, will have more rear weight percentage in the static state, so much so that even with the decrease in weight transfer due to the longer WB, the end result will be more rear weight under acceleration. Think top fuel drag racing car. You can run the numbers and check me.

Front and Rear Roll Couple (Roll Stiffness) and Spring Rates

Looking at the lateral weight transfer formula, spring rates have nothing to do with how much weight transfers aside from their input on CGH. What springs do control though is where the weight goes when it is transferred. If it goes to the front, the car is tighter because it is transferring the weight from the left front to the right front keeping the rear tires more equal. If we only increase the right front spring rate, more weight transfers up front resulting in a tighter car.

Fundamental Truth #2: A softer spring will transfer less weight to that corner of the car than a stiffer spring.

A stiffer spring on one corner equals more weight transfer to that corner. That is why a stiffer right rear spring makes the car looser. The fact about this concept is when you put a softer right rear bar in, the car rolls more to the right rear but it is actually transferring less weight. That is why it gets tighter. Although the same amount of overall weight is being transferred, the weight is being transferred up front and less in the rear. Imagine if you took the bar out of the right rear, the car would roll obviously to the right rear but would transfer no weight there; all the weight would be transferred up front. Again, this is a fundamental law of vehicle dynamics; I am not making this up.

Dirt track racers have botched this stuff up so bad, it took me 27 years to flush it all out of my head and rethink it all.

Things are not always as they appear. It may look like the car is transferring a great deal of weight to the right rear and that the car really is tighter than it was before. The old idea of side bite seems to be true, but I assure you, it is not. Forget the old idea of side bite, it is wrong!

Bottom Line: When you see a car rolling on the right rear, the car is tight because it is transferring less weight, not more weight. It is keeping more weight on the left rear resulting in a tighter car. It is not rolling more weight on the right rear pushing it into the dirt more making the car tight.

To give the car more lateral traction, go to a softer right rear bar or a stiffer right front spring. A stiffer left rear bar will have two effects: raising the car (higher CGH), and adding static left rear weight. This will tighten the car in the lateral and the longitudinal directions depending of course on the size and shape of the track.

In the automotive world this concept of front and back spring stiffness is called front and rear roll couple or roll stiffness. An increase in front roll couple makes the car tighter and a decrease in rear roll couple makes the car tighter. As we stiffen front roll couple, more weight transfers up front and less transfers in the rear. The rear tires stay more equally loaded and the car gets tighter.

Right side springs affect the cars roll couple when negotiating a left hand turn and the car is rolling to the right. Because we do not turn right, the left side springs do not play much of a role except for static weight and ride height considerations. Unless of course, you race with a wing.

Winged Down

Asphalt formulas or vehicle dynamics concepts were never devised for winged sprint cars. The huge wings and side boards that we run are unique in the racing world. No where else is there a large top wing that has such huge side boards to cause such a drastic side force. Wings actually cause weight to transfer to the inside of the car for a portion of the turn. This happens because when we enter the turn with such high speed and then all of a sudden we turn the car and make our wing panels face a huge wind. The wind pushes so hard on the side boards that it overcomes the weight transfer caused by the side g-force. Imagine going 90 MPH in your car and trying to hold a sheet of plywood up, can you imagine the force?

In these two pictures the cars are all winged left and transferring weight to the left side of the car in corner entry.

We need to start looking at the corner in two distinct phases. These phases will change from track to track. The first phase is what I will call winged (rolled) left, or winged down. The first part of the turn when the car is winged (rolled) left due to the wing side boards, and roll right, which occurs when the car slows enough that the g-force is greater than the side force generated by the wing panels. The bigger the track the longer the winged left stage will be. As a driver you need to pay attention to how the car is working when it is winged left and rolled right and make your changes accordingly. The period of the winged down or roll left phase of the turn is different for each size and shape track, and it also changes at the track during the night as the track goes slick. A track with tighter turns relative to the length of the straight will have more winged left effect; tracks that are larger will also have more winged left effect.

In the above pictures the cars are now transferring weight to the right side of the car in the rolled right phase on corner exit. Interestingly, in Robbie Kendall’s #55 car, the left front shock is topped out and just about off the ground. All the weight that was on the left front has now mostly transferred to the right rear and right front. He can still steer off the right front, so this is not a bad thing.

Up until now, most of what we were using to set the balance of our car was the right side springs. Now that we recognize that weight transfers to the inside or the left side of our car for a portion of the turn we need to look at the left side springs and offsets. Everything we applied to the phase of our car when it was rolling right needs to be applied on the left side because it is transferring weight to the left.

Big Concept: Left side springs and offsets control the handling during the winged down phase, right side springs and offsets control the roll right phase.

Increasing the left rear spring rate will loosen the car while winged down because it will increase the roll left rear roll couple stiffness and keep the weight on the front tires more equally loaded. Softening the left rear spring will tighten the car during roll left or winged down. Of course when our car hits the ground, the spring rate not only becomes infinite, but the weight is now transferred through the frame rail to the track and not the tire to the track. The tire gets a whole lot better traction than the frame rail. Bottom line, don’t let the car bottom out.

Advanced Racing Suspensions (ARS) has an amazing shock that helps the problem of the left rear bottoming out during corner entry. They call it the WX shock. It acts like a three stage shock that really stiffens up when the shock sees high velocities like that of winging left on entry. They make a WX version for the right rear as well that helps running the cushion and taking bumps. This stiffening effect will keep the left rear from bottoming out. If you do not have one of these shocks, a bump rubber is a good fix and allows you to run a softer left rear torsion bar to help tighten up on entry. Keep in mind that when the car gets into the bump rubber on the left rear shock, the spring rates also climb very high. This will also make the car loose on entry, but is much better than bottoming out.

This picture shows the proper use of a left rear bump rubber. Use the shims to adjust exactly when the car gets into the bump rubber. Try to get the shock to hit the bump rubber about ¾” before the frame hits the ground.

Winged Down Corner Weights

During the winged down phase of the turn, when weight is rolling from the right rear to the left rear, more static right rear-left front weight will make the car tighter. The reason is that starting out with more right rear weight, when the car transfers to the left the end result will be the two rear tires will be more equal in weight.

The opposite is true during the roll right phase: more initial left rear-right front weight will result in a tighter car. Got it? When we add left rear right front weight or what some might call cross bite, the car will get tighter during roll right, but looser during roll left.

Again, think about the size of the track, how long the winged down phase is, and where you are trying to tighten the car when determining where to put your turns.

Tire Offsets

Same theory applies: moving the right rear in will add more static right rear weight and will cause more weight transfer. These effects are good for tightening up the car when winged down, but opposite for roll right.

More wing speed means we need to keep the right rear in further to get the car tighter. A slicker track means less weight is transferring to the right rear during roll right, but generally our winged down phase is just as long as it was on a tacky track, so the right rear can be moved in. However there is a point of no return where you can go to far and have too much weight on the right rear. Also, remember in our lateral weight transfer formula, a larger TW number will decrease weight transfer which will increase our rolled right traction. So there is a balance. The exact numbers vary from car to car, track to track, and surface to surface.

There is also a jacking affect that takes place when the right rear is moved in. It causes the car to lift up on the left rear raising the CGH creating a lot of drive. This can be very beneficial on a small track. On a big track, we can’t move the right rear out because it will loosen the car on entry due to the loss of right rear weight.

The left rear tire can be moved out to tighten up when winged down. This is a result of the weight transfer formula being applied to roll left. A wider TW or more offset will result in less weight transfer. However, moving the LR out will decrease LR static weight which will hurt rolled right traction.

Summing it Up

If you are loose when the car is winged left, change left side springs and/or left side offsets and/or add right rear-left front weight. A stiffer left front spring or softer left rear spring will tighten the car in this phase. Move left rear out to tighten or move left front in to tighten.

If you are loose when the car is rolled right, a stiffer right front spring and softer right rear spring will tighten car. Static weight adjustments to tighten the car while in this stage are: add more right front-left rear weight (crank turns into the left rear).

It is a fine line and exactly where that line is on every track for every track condition. Experience is your best friend.

Generally, softer rear springs or torsion bars will make the car tighter, although you need to raise the rear to get the CGH back to where it was before to keep the longitudinal traction up. Stiffer front springs or torsion bars will make the car tighter. However, too stiff of front springs will cause it to be inconsistent as it will push when it sees a small bump. On a slick smooth track it can be ok to go pretty stiff on the front, but don’t try it on a track that has some imperfections in it.

For longitudinal traction (forward drive) keep the car high, just know that this may loosen the car where the car is needing lateral traction. I found on small tracks that are slick, generally, raising the car more is the way to go (within reason). This is because the winged down phase is real short and the car will start spinning the tires quicker because of the gear ratio allowing for greater torque on the tires. On bigger tracks, 1/3 mile or larger, it is better to keep the car lower to the ground. There are optimum points where balance is achieved, just pay attention to what you car is doing, and now you know the proper adjustments to make. Wingless

Wingless racing is a little easier to understand as we only need to look at the roll right factors. Of course with less overall traction available due to the air foil being gone (free down force), spinning the tires from lack of longitudinal traction becomes more of an issue. A higher center of gravity and more right side offset is advantageous. As mentioned earlier, when moving the right rear out, the jacking effect of raising the CGH will be gone, so you will need to statically raise the CGH to compensate.

Horsepower has a lot to do with which factors you want to focus on. Other classes of sprint cars will need to focus on different parts of the adjustments than 600cc sprints do.

Roll Centers

The roll center of your chassis is the pivot point around which your chassis rolls. The roll center is controlled by the lateral linkage; this linkage controls the location of the axles under the chassis in the side to side or lateral direction. The roll center axis is an imaginary line drawn from the front RC (roll center) to the rear RC. The amount of chassis roll is a function of the distance between the roll center axis height and the center of gravity height. The longer this measurement, the more roll, the shorter measurement or higher RC, the less roll.

Although roll centers play an important part in how your car handles, it does not control how much total weight transfers, only where and how it transfers. We can control the weight transfer to the front or to the rear through the difference in RC heights between the front and the rear. It works just like roll couple or roll stiffness that we talked about earlier.


A higher RC on one end of the car will result in a stiffer roll stiffness on that end of the car causing more of the total weight to transfer at that end of the car. Raising the rear RC will increase rear roll stiffness causing more of the weigh to transfer in the rear creating a looser race car due to the left rear/right rear tires loading being unequal.

Although we don’t usually change this at the track we must consider the roll center location left to right. As we move the roll center to the right the roll stiffness increases because the lever arm between the CG and the RC increases. It also changes the angle of this lever arm. We need to calculate the cosine of the angle multiplied by the distance of the arm.

Finding the Roll Center

The roll center of a panhard bar linkage is located directly in the center of the bar. It is very easy to find.

The roll center of a Jacob’s ladder is located where the two center lines created by the strap’s pivot points intersect. When you change the hole locations where the straps mount, it changes the RC height and/or the RC side to side location. One major difference between the two designs is that the Jacob’s ladder’s RC goes up when the car rolls right, the panhard bar’s RC moves down when the car rolls right.

Elastic and Geometric Weight Transfer

We can control whether the weight transfers through the springs or the lateral linkage by controlling the height of the roll centers. As we raise the RC, more of the weight is transferred through the linkage, as we lower the RC more of the weight is transferred through the springs. If we made the RC axis higher than the center of gravity of the car, the car would actually roll to the inside of the turn, like a boat, but the same amount of weight would be transferred to the right side of the car, it’s just that all of the weight would be transferred through the linkage.

The weight that is transferred through the linkage is call geometric weight transfer. The weight that is transferred through the springs is called elastic weight transfer.

Although drivers generally feel more comfortable with a car that does not roll much, resist the idea to increase geometric weight transfer too much as it leads to a car that does not absorb bumps as well.

Anti-squat Anti-squat is a concept used to determine how much the rear of a chassis will squat under acceleration as a result of the rear geometry. 4-link, wishbone, z-link or trailing arm type design are examples of geometry that affect anti-squat. Conversely anti-dive is used to describe how much a chassis nose dives under braking. Anti-dive is not something we need to concern ourselves with much on dirt as the braking force is not real high and wheel hop or chatter under braking never occurs.

Again, we already know what factors affect how much weight transfers to the rear under acceleration. Anti-squat or how much the rear squats from rear geometry is not one of them. Looking at that formula, to get max weight transfer to the rear, we need to raise the CGH. Knowing this fundamental truth, designing the rear geometry to make the rear squat actually hurts our cause. Yes, we do want the rear to squat, but not because of the rear geometry, but because the weight is transferring to the back. We want the rear geometry to drive the rear of the car up (a lot of anti-squat), raising the center of gravity, when the CGH is raised, more weight will transfer. As more weight transfers, the rear will squat.

Calculating Anti-squat: this is not so straight forward and I will not go into the numbers, just know that as you raise you linkage points in the front (wishbone, 4-link, and the top rod on a z-link) the anti-squat will be increased. It will resist squatting resulting in better forward bite because it will keep the CGH higher.

If you calculate the anti-squat on a typical wishbone, it is much more than the typical z-link design used on common Jacob’s ladder cars. Chain Tension

As the pivot point of the rear axle is moved to achieve different anti-squat percentages, it changes how loose and how tight the chain gets as the chassis rolls. If we can achieve a pivot point (or instant center as engineers call it) real close to the front sprocket center, the result will be a chain that does not change tension as the chassis rolls. This is how the Hyper chassis wishbone cars are designed. If the instant centers are drastically moved the result may be a chain that will not stay on. Also know that the chain force will cause the left rear of the car to lift up or squat down depending on exactly where the instant center (IC) is. If the IC is below the front sprocket, the car will squat, if it is above the front sprocket it will lift up. A car that lifts up on the LR under load is a little hard to drive.

I Am Humbled Even after 34 years of racing micro sprints and mini sprints, I am still learning, and I hope it never stops. Test these ideas, develop your own conclusions, and watch my website as new truths unfold. I hope this paper inspires you and makes you want to learn more. There is a lot of information available online, just search for some of the terms I used and you can learn volumes.

Dirt Late Model Newsletter – Advanced Racing Suspensions

Dirt Late Model Newsletter


November 1, 2010 through January 31, 2021

Now that the racing season is over, this is the ideal time to start preparing for next season. Many of our customers send all their shocks in to be dynoed at this time of the year, so that they can be checked after a long season of racing. To urge all of our customers to check the condition of their shocks before next season, we are reducing the cost for shock dyno service on any A.R.S. shock to $5 per shock until January 31, 2021. This reduced shock dyno offer will give you a chance to evaluate the condition of your shocks after a season of racing and at the same time review any new valving combinations. When sending your shocks to us for service, please enclose a note with return address, phone number, and a brief description of what you would like done to your shocks. A shock maintenance form is available from our website. After shocks are dynoed, we can call you with the results and discuss the outcome of your shocks or any new shock combinations. Many customers send all their shocks to us during this special dyno offer, so send your shocks in as early as possible to avoid any delays in preparing for next season.



The 4” top (extended load) spring on the left rear preloader has been changed to a 4” x 050 lbs. spring. Softening this spring has created more traction on corner exit. The original stiffer top spring would break traction on slick conditions. The 4” x 50 lbs. (#3204×050) spring will allow the extended load to be between 50 lbs. and 150 lbs. The 20” x 50 lbs. spring on the preloader has not changed just the extended load spring.

Right front bump spring

The double bump spring has been a big gain this year. This combination allows you to compress the right front and make it turn but not bottom out the cross member. The driver will have a lot more confidence in driving the chassis harder if the rate in the right front spring package limits the travel instead of hitting the cross member and skating up the track.

Right rear double spring combination

The double right rear spring combination is nothing new, but a lot of racers don’t know how good it works on a dry slick track. The less right rear load and the harder the compound tire the better it works. When the right rear radius rods drive the frame up it unloads the right rear spring. Which in turn dramatically reduces the load on the right rear tire. This is good for heavy tracks but kills the side bite and forward traction on dry slick tracks. The lighter secondary spring keeps loaded when the main spring becomes unloaded. Now that front suspensions don’t raise up like the chassis of the past right rear grip is more important than ever.

Valving Updates

Left Front

There are a couple of things that need to be addressed in the left front shock dampening. The rebound holds cross weight in the chassis which creates forward bite. Too much rebound pulls the tire off the ground and makes the chassis push mid-corner to exit. The rebound dampening requirements change on a short tight corner track versus a fast sweeping corner track.

The compression on the left front is adjusted for corner entry. If the chassis is tight on corner entry, you need to soften the compression. When the track dries out and your chassis gets free on entry you stiffen the compression. After we dyno your shock, we will send you dyno sheets showing your complete adjustment range. We will mark your dyno sheets showing you how you need to adjust your shocks to accommodate changing track conditions.

Right Front

The right front is possibly the most important shock on the car. The rebound dampening in this shock controls the chassis attitude throughout the corner. Too much rebound hurts forward bite, and too little rebound unloads this corner creating a push condition. It is important to have enough low speed rebound to hold attitude but not too much high speed that it makes this corner too rigid.

The low speed compression needs to be soft enough to allow the chassis to get down on corner entry and enough high speed to keep the chassis from slamming the bump stop on corner entry. We have built special pistons just for the right front shock to accomplish these requirements.

This corner is very critical on shock and body lengths for different chassis builders. The right front shock body needs to hit the bump stop at the right time and rate. We can set the bump stop and spring load for you with our spring smasher while we are servicing your shocks.

Right Rear

The right rear shocks have a new valve curve (T/C) that creates more traction than ever before but still creates enough high speed control to run the cushion. This has always been the challenge to provide both of these requirements. The rebound range allows you to soften the rebound enough for heavy track conditions, and then stiffen the rebound for maximum traction. We lock in the compression dampening and adjust the gas pressure for heavy to dry/slick tracks. After we dyno your right rear shock we will send you dyno sheets showing your complete adjustment range. We adjust this shock more than any shock on the car to accommodate changing track conditions.

We now change the right rear spring load more than ever. The standard is a 225 spring with spring rubbers or many customers prefer the double spring (inner & outer) combination for dry slick conditions. Whatever your spring combination is you need to stay on top of your load numbers as track conditions change throughout the night to create the correct balance.

Left Rear

The left rear (behind) shock and spring combination has become more critical than ever before with the requirements on this corner of the race car. It is necessary to have a soft ride height rate so the chassis sets down to get the spoiler thru tech. Then have the correct extended rate to provide maximum traction. We can create this spring combination with the spring pre-loader. Every chassis manufacturer has different heights and load requirements. We can create a good combination for you regardless of the brand of chassis that you are racing.

The left rear(front) or (top) shock provide enough extended rate to hold the left rear up and make sure the left rear corner does not fall down and let the chassis lose the rear steer. A fine balance of compression dampening and gas pressure provides this combination. This shock’s main function is to hold the left rear corner up under deceleration or part throttle conditions. It does not provide traction except to keep the left rear bars in the correct angle which creates traction. This shock is very critical in making sure you have the correct combination to develop maximum traction. Some racers remove this shock on dry slick conditions but you must have enough L.R. back extended rate to make this work.

Fifth Coil

The secret to this unit is to have a stiff rate for instant traction but create enough travel (3-1/2”to 4”) to make the torque arm pick up the chassis and plant the tires in the track. If you have less than 3” of travel, your chassis will not have maximum traction. We create this combination with the P/D fifth coil assembly. The 1st inch of travel is the stiffest rate with the 2nd and 3rd inch of travel getting softer for maximum travel. We have been running this unit for years, but it is high maintenance and if it is not clean it will not work. We have just built new sliding floaters that are more dirt and dust friendly. When this unit is set correctly and it moves freely there is nothing better for the 5th coil. We can update all old units with these new floaters and make this unit much more reliable.

All chassis builders are making the frames stiffer and out of better tubing to make cars more repeatable throughout the season. This makes the shock dampening and spring rates (load rates) even more critical.

The Most Opinionated Racing Message Board In The Universe

View Full Version : LR spring theory…

dfhotlm33c So, I know this has been discussed ad nauseum, but I am trying to pinpoint the theory for my own application…

It seems as though the consensus here, and on Afco’s tuning guide is that a softer LR spring will generate more traction…

Virtually every setup sheet (GRT, Rocket, Mastersbilt) recommends stiffer LR than RR…

The recommendations here seem to be split..

My analysis: A driver like myself, still somewhat green and not adept at trail braking on a track that slicks off and requires that you get all the way out of the throttle, would generally benefit from the stiffer LR..

Put another way..I have 200 LR, 225 RR as of last night…assuming the car was decent on a very slick track, what should I expect out of the car if I was to experiment with stiffer LR?

Egoracing Less body lift which will result in less weight transfer and less side bite as a result of less leverage on the suspension.

F22 RAPTOR There is a greater “Hike-Up” potential from a “SOFTER” Spring having more stored energy, because it compresses more to hold up the same weight as a “STIFFER” spring. A “STIFFER” spring can run out of height before you get done climbing the bars and bars alone don’t generate the most “complete” traction. This is where the, “STACKED SPRING” setup came from, even greater stored energy is possible than with a single spring. When trying to increase forward traction ONLY, several factors in setup must work together, not just a spring change. Like Bite for instance or Rear/Left side percentage or RF spring rate… And on and on. Hope this helps.

Matt49 All good answers so far but let’s be careful how we use the word “traction”.

The softer LR allows the car to get up on the bars faster which does two things:

1) Transfers weight laterally to the RR and increases j-bar angle both of which increase side-bite

2) Increases 4-bar thrust angle which increases LR drive

The combination of these two things might be considered “traction” but I just don’t like to think of it that way.

lovinlatemodels Not gonna say that this thread is right or wrong but a 200 spring never gave our car more lift or traction infact we always had better luck on a 250 or 275 spring and always had plenty of lift on the LR to the point we weren’t even on the spring it was all lift bar providing the traction. I perfer on tuning to the driver and not what everybody else is doing.

Egoracing Not gonna say that this thread is right or wrong but a 200 spring never gave our car more lift or traction infact we always had better luck on a 250 or 275 spring and always had plenty of lift on the LR to the point we weren’t even on the spring it was all lift bar providing the traction. I perfer on tuning to the driver and not what everybody else is doing.

IF your car is going to transfer 800 lbs to the right in the turn and you are on a 200 lb spring it is going to relax the spring (read that as raise the chassis) 4 inches. If you are running a 275lb spring it is going to relax 2.9 inches. The added movement is more bar angle AND it raises the chassis which used the center of gravity better. It is that simple, if you were not getting more movement then there was something wrong that was not allowing it to transfer. 99% of ALL 4 link cars are not on the LR spring once into the corner when setup right. It is how fast you can get on the gas and drive away from the car behind you where the better setup is faster.

MasterSbilt_Racer Not gonna say that this thread is right or wrong but a 200 spring never gave our car more lift or traction infact we always had better luck on a 250 or 275 spring and always had plenty of lift on the LR to the point we weren’t even on the spring it was all lift bar providing the traction. I perfer on tuning to the driver and not what everybody else is doing.

You may have been in a stop and go situation and didn’t have enough initial wedge to get the car up on the bars.

How an adjustment effects the car depends on what it is doing before and after the change.

dfhotlm33c Masters…I totally understand that concept…however, I am trying to understand why the disparity between “boots on the ground” like at this site, and the recommendations on virtually every setup sheet, book and adjustment guide I can find (Excluding Afco, which agrees with the theory that softer spring= more LR hike, better chance of remaining loaded and hence better traction) that usually recommend a stiffer LR to tighten car. The setup sheets for my car specifically recommend using stiffer spring for slicker track, as does Mastersbilt and GRT…and being a math/physics person, I understand the principles both use to explain what should happen

This is why I mentioned the relative inability to trail brake at this point and the type of track..wondering if someone that dumps the throttle would experience a different effect than someone who trail brakes with better success..

and now you bring the wedge concept into the picture…I lowered the wedge from 150 to 50 and experienced some success, the car actually didn’t nose to the wall at throttle application…

Sorry for the length of posts and such…just trying to get a sense of what “should” happen with various changes so I can justify making changes at the track…still trying to dial in a car that is just moderately comfortable to drive..keep swinging from one end to the other..

MasterSbilt_Racer Masters…I totally understand that concept…however, I am trying to understand why the disparity between “boots on the ground” like at this site, and the recommendations on virtually every setup sheet, book and adjustment guide I can find (Excluding Afco, which agrees with the theory that softer spring= more LR hike, better chance of remaining loaded and hence better traction) that usually recommend a stiffer LR to tighten car. The setup sheets for my car specifically recommend using stiffer spring for slicker track, as does Mastersbilt and GRT…and being a math/physics person, I understand the principles both use to explain what should happen

This is why I mentioned the relative inability to trail brake at this point and the type of track..wondering if someone that dumps the throttle would experience a different effect than someone who trail brakes with better success..

and now you bring the wedge concept into the picture…I lowered the wedge from 150 to 50 and experienced some success, the car actually didn’t nose to the wall at throttle application…

Sorry for the length of posts and such…just trying to get a sense of what “should” happen with various changes so I can justify making changes at the track…still trying to dial in a car that is just moderately comfortable to drive..keep swinging from one end to the other..

It completely depends on what the car and driver are doing. If the car is near ride height when you gas up, a stiffer spring will aid drive. If you keep the car barred up, a softer spring will aid drive.

For a driver who is a friend of mine, one works for some tracks and the other approach works for the other tracks. You have to be able to see what the car is doing to make the correct adjustment. As I have said on here many times, there is no setup sheet out there that is right 100% of the time. It simply isn’t possible.

let-r-eat This could be a good thread. Some of these tuning guides IMO are taking LOTS of things that are important out of the equation. Brake pressure, throttle input, steering inputs……etc etc etc.Traction is matching the friction coefficient of the rubber and the surface. A stiffer spring can overload this earlier or the softer spring can dampen too much allowing slippage. The speed and amount of weight transferred plays a critical role as well.There is no clear cut answer to your question.

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It’s Worn • Why Dirt Racers are Stacking Springs

The use of stacked springs has become commonplace among many top Dirt Late Model teams. It wasn’t always that way. As far as I know, the first test using stacked springs in a dirt late model occurred in March of 1998 at Eldora Speedway. Coincidentally, I was there, and I was surprised.

We were there, I assumed, to test a new setup arrangement I had developed for the upcoming Dream race that seemed to work out very well. My friends at the test wanted to see how stacked springs would work, so we tried them too. Although the stacked spring concept as it was arranged then did not work well at the then high banked Eldora track, it would eventually gain traction for use at lower banked tracks.

The stacked spring concept began with desert racers in the Baja Pro Trucks as far as I can ascertain. I’m sure someone will correct me if I am wrong on that. Anyway, those trucks needed a compliant spring that gained rate, but it needed to be very long due to the high amounts of suspension travel. The same is true for the right front and left rear corners on many Dirt Late Models in today’s racing.

The use of stacked springs, first in the right front of the Dirt Late Models, allowed the car to run on a very soft spring rate on entry to the corners until a heavier rate was needed through mid-turn and then off the corners. Now, in today’s racing, the stacked spring concept is being used at the left rear also and sometimes in the right rear of those cars.

If you use stacked springs in your car, or you are thinking about switching to stacked springs, here are some important tips and technical information you will need to know. This mostly comes from professionals in the racing spring business I have talked to and who work directly with race teams. I admit that I knew very about the use of stacked springs before I researched and sought out the help of these individuals.

Definitions Of Stacked Springs – Basically there are two ways to run stacked springs. One is called Stacked springs because all you are doing is stacking two springs in series, with the same or different rates, to achieve a longer spring that is a softer rate than either of the springs used.

If you stack a 10 inch 400 ppi and a 6 inch 400 ppi spring, you get a combined rate of 200 ppi. You may not be able to find a 16 inch 200 ppi spring, so this provides more spring length to use. We’ll go over how to find that rate later on.

The other way to use stacked springs is to use the Dual Stage system. This system is also a stacked spring in that you use two springs on top of each other in series. The difference is that you also use a stop mechanism that eliminates the travel of one of the springs at some point of shock travel to where the car is then riding on only the one spring.

With the Dual system, you can run a softer spring on the top and a stiffer spring on the bottom. As the shock travels, the divider between the shocks moves up the shock body. At a predetermined (by you) point, the divider hits the stop and the top spring is no longer able to compress.

Since only the bottom spring is now the only one working, its rate is what the car runs on as long as the shock is compressed at least that far. So, for example, if we want to run a 450 ppi (pounds per inch) spring through the middle and off the turns, but require a much softer spring rate to enter the corner with, we can stack a 300 ppi spring on top of a 450 ppi spring.

Using the Stacked formula to find the combined rate, we use the Top Spring rate times the Bottom Spring rate divided by the Top Spring rate plus the Bottom Spring rate. To find the example rate, we multiply 450 times 300 = 135,000. Then we add the two spring rates to get 750. Dividing the two, 135,000 divided by 750, we get a 180 ppi combined stacked spring rate.

So, on entry, our car rolls in on a spring rate at the right front of 180 ppi. Once the shock travels to a predetermined compression, the top 300 ppi spring is eliminated and the car now runs on the bottom 450 ppi spring at the right front until the shock de-compresses and the spring divider is no longer contacting the stop.

Another Dual Rate System – I will throw this in at this point. There is another Dual Stage system being used by some teams. It involves using a bump spring, or bump stop, on the RF corner. Just like the Dual system I described above, the rate changes as the shock travels.

With the bump spring, or for that matter bump stop, the car is suspended by the normal ride spring until it travels a predetermined amount. Then the bottom of the shock body, plus any stackers, contacts the bump and the ride rate is now the combined rate of the ride spring plus the bump rate.

The drawback to trying to go this route on dirt is that most bump springs, and especially the bump stops, do not have much travel before they coil bind or compress to solid. Some teams will stack two bump springs to get more travel, but now that stack equals a much softer bump spring rate.

Two 500 ppi bump springs that are stacked will equal a spring rate of only 250 ppi. To get back to the 500 ppi rate of just one spring, you would need to stack two 1,000 ppi bump springs.

Which Do I Run? – The choice of which to run, Stacked or Dual, depends on which corner you will be working with. Generally, the Stacked system works best on the LR corner to provide a longer spring to help it stay loaded when the LR corner hikes coming off the corners.

The same Stacked system will not work very well on the RF because the soft rate would cause the RF corner to travel too far. And, it would not produce the higher rate needed to gain loading for the RF and LR corners coming off the corners. So, we use the Dual system on the RF.

The combinations for each, the Stacked and Dual systems, are many. You will need to determine what you want to accomplish and then decide on the spring rates that will get that done for you. For the LR corner, make sure you end up with a combined rate that will work with the RR spring rate to balance the car. Too stiff and the car will be too tight in and through the middle. Too soft and the car will be too loose in and through the middle.

Important Considerations – Here are a few important considerations and tips on how to put together your stacked systems. You cannot just install two stacked springs in your car on any corner and just go racing. There is some shop preparation that is required.

First off, a longer spring will tend to bow more than a shorter one, no matter how good your spring is. This may be a problem that can be solved. On most quality springs, the ends are 180 degrees opposite where the tips on each end are pointed. This tends to offset the bowing tendency.

If you stack springs, you will need to arrange the springs so that the bowing tendencies of the two springs offset one another, just like the design in individual springs. This takes time and experimentation. How do we do that? We eliminate bowing by rearranging the location of the two springs after compressing the system on a commercial coil-over spring compressor to find a position for the springs that has less bowing.

Adding bearings to the top and bottom of the assembly will also help prevent bowing of the springs. The two springs must be allowed to twist, or wind and unwind, as the shock travels. That is the way springs work all of the time.

What Else You Need To Make This Work – Most teams, if they are going to get the most out of the stacked spring systems, will hire a shop that has a coil spring force measuring rig, or they will buy their own rig, to help in the setup of the stacked spring system.

These rigs measure force at predetermined compression amounts of the shock/spring combination. This is not a hard concept to learn and understand if you follow along with the overall picture. To do that, we need to mentally separate force from spring rate, they are two entirely different things.

Force is the overall work that the spring is doing based on how far it is compressed. A 500 ppi spring that is compressed two inches has 1,000 pounds of force. It gains 500 pounds of force for every inch it is compressed. The designation, 500 ppi, means that for every inch of compression, the spring gains 500 pounds of force. That is why it is labeled 500 pounds per inch.

In order for us to maintain our ride heights we had using our old one spring system, we need to measure the shock length at ride height and record that number. This is true no matter which corner of the car we are working with. With the LR using the Stacked system we also need to know how far the shock will extended when the rear is hiked up so that we install a Stacked spring system that is long enough.

At the LR, we compress the Stacked spring and shock in the Force rig and adjust the spring height so that the force at compressed ride height is the same. If we compress the shock to the ride height amount and we end up with too much force, we back off the adjuster until the force is the same. Then our ride height will not change when we install this Stacked system.

For the RF corner, we will be running a Dual system. For this, in addition to finding ride height force, we also need to know how far the shock compresses at mid-turn when running a single spring. This motion produces its own force that we need to duplicate in the Dual system.

At the RF, we do the same as we just did with the LR for the overall Dual system ride height. For the transition from the stacked rate to the single spring ride rate, we need to know the average shock travel at mid-turn. Then we use our Force rig to find that force number in pounds.

We usually want to hit that mid-turn force number at some point after the spring separator has contacted the stop that eliminates the softer spring and when the RF corner is riding on only the higher single spring rate. The total amount you end up compressing only the single spring is something you will have to experiment with.

This timing has a lot to do with how long into the corner you want to be on the softer, Dual spring rate, before transitioning to the single higher rate. That is why most consultants suggest on-track testing to tune the transition point.

Shocks To Use With Stacked Systems – The shock package you will need for your stacked system is a little different than what you might be use to for single spring applications. We need to understand what we are trying to accomplish and then think out our shock rates.

For the RF, we need the shock to control the force levels we are working with at mid-turn and off the corners. By control I mean rebound settings in the shock. Those forces will be already known if you run through what we discussed above. They will be higher than standard because one of the benefits of the stacked Dual system is that it travels farther and generates more force.

For the LR corner, we want the shock to extend more easily and therefore the rebound rates for that shock would be lower than normal. Also, when we exit the corners, there will be some extension initially, then some compression of the shock and spring, so we might consider increasing the compression setting to take advantage of that to create more loading of the LR tire for late exit traction.

Outlawing Stacked Springs – It has been discussed within come sanctions, and enforced in others, that stacked spring setups be disallowed. The reason stated is to save the racer money. Many of these very same sanctions allow bumps stops and bump springs. Let’s examine the argument.

Cost is relative to many things. We know springs last a very long time. So, any investment in springs for setting up stacked spring systems will be a one time, or long term investment. And it can be argued that the teams may have the springs needed for the stacked spring systems already lying around the shop, unused. Now the cost is only the hardware needed to go on the shock and those parts are relatively cheap.

If bump stops are allowed, we know they don’t hold up to the rigors of dirt racing and need to be replaced on a regular basis, so the cost of those systems, while relatively cheap in the beginning, becomes more expensive in the long run.

The force rig that should be used by the teams to setup the stacked spring systems can be rented, or shopped out to a consultant, much like we do with our shocks. If the team does invest in the force rig, it is basically a spring tester designed to rate the spring/shock combination. Many teams already have those, and if not, they need them.

Getting a car to handle better makes for better racing and it is safer. The reason it is safer is because the cars no longer need to force the front end to turn like before these systems came out. With less sideways action, there is less contact between the cars and less overall damage from contact.

I really don’t see what the big deal is. Modern super late models on dirt run custom built engines that cost upwards of $40,000 in some cases and a stacked spring system cost pales in comparison. The difference between the stacked system and a single system is around $300-400 for parts. One crash will eat up more parts that that. So, I’m not convinced there is any realized savings in outlawing stacked spring systems for dirt racing.

Conclusion – The use of stacked springs in either configuration can make your car faster and easier to drive. If you run stacked spring systems, or intend to convert to stacked systems, be sure to follow the simple rules we have presented. Also, consult with your spring supplier, shock supplier and those who manufacture the force rigs so that you can get the most out of your application.


Eibach Springs


Gale Force Suspension


Hyperco Springs






The post Why Dirt Racers are Stacking Springs appeared first on Hot Rod Network.

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Circle Track Magazine

One of the primary components used to set up our car is the spring. When we have chosen the correct spring rates, as well as the corresponding moment centers and weight distribution, we get a balanced and fast race car. All too often we crutch the car using inappropriate spring rates that serve to balance handling but don’t yield consistency.

In order to win races, our car must be fast, not only right out of the box, but also at the end of the race. In fact, many races are won by cars that may not be the fastest in the early laps of the race, but prove to be faster than the field at the end of the race. The key is to make sure we give the car what it wants so it will be fast as well as consistent.

In a 25- or 30-lap sprint, a jackrabbit setup may work relatively well. A team with a well-balanced setup that starts off a couple of tenths slower for the first 10 to 15 laps may not have enough time to take advantage of everyone else’s lap times falling off as the race progresses. But in a 50- or 100-lap race, the car that falls off less as the laps move past Lap 25 or so will have a much better opportunity to win. A more balanced car will have the best chance to win a race of any length.

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Many odd arrangements of springs have been tried, and some of the racers across the country are trying new methods to find a balance. There may be dozens of combinations of spring rates, moment center locations (front and rear), and weight combinations that will balance the car. Here are some considerations concerning springs when balancing your stock car.

Knowing the True Spring Rate The first thing to consider when deciding which springs to use in your race car is the spring rate for each of your springs. Each spring must be tested properly. We need to know the spring rate of our springs at the ride height and range in which they will work in conjunction with the corner where they will work.

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Theoretically, we should rate a spring based on which corner of the car it will be used because of the different ranges of motion. For the LF spring we measure the height of the installed spring, remove it, and place it in the spring rating device. It is then compressed to the previously measured height before rating. For a conventional setup, this corner may bump and rebound up to an inch or more. The rate is checked up and down 2 inches from the installed height. For softer spring setups, this corner may travel up to 3 inches or more in compression.

The RF spring is mostly in compression, or bump, so we compress that spring to the installed height and then further compress it 2-4 inches to find the average rate within the range. Remember that there is an installed motion ratio and the spring is moving less than the wheel, so we don’t necessarily need to compress the spring as much as the wheel moves.

The RR spring is also mostly in compression, so it is compressed initially to ride height and then up to 3-4 inches further, depending on the spring rate. For big bar and soft spring setups on asphalt, the right-rear spring is much stiffer and travels much less than a spring with a conventional rate.

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The LR spring reacts similarly to the LF spring and is in some rebound on entry and some compression at midturn. This spring is rated by compressing to ride height and then up to 2 inches up and down. For dirt car applications, this spring may rebound quite a bit as the left side jacks up for some slick track setups. In this case, the spring may be near or past the free (unloaded) height at midturn and compressed down the straightaway.

Front Spring Split The overall trend in circle track racing, for both dirt and asphalt, has been to reduce the rates of the front springs. For some situations, there is even a move to a softer right-front spring.

Dirt cars can benefit from a softer right-front spring on flatter dry-slick tracks. On flatter asphalt tracks, corner entry is enhanced with a softer right-front spring.

The front spring must be increased for high-banked tracks, and it is often necessary to stiffen the right-front spring more than the left-front spring.

No matter what the stiffness is for our front springs, we need to compensate at the rear in order to balance the car’s suspension dynamics. Dirt Late Model teams are running much stiffer right-rear springs than ever before and seeing a lot of success. Asphalt teams who try the BBSS setups tend to overdo the stiffening of the RR spring.

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The very stiff RR spring does not work on flatter tracks that are rough. The car experiences excess bouncing going over ripples and bumps. There is a limit to how stiff a corner can be.

On the higher-banked racetracks, teams trying soft front springs quickly change to a higher rate when the car bottoms out. Common sense tells us that added downforce will overcome the light spring rate and either the springs will go into coil-bind or the chassis will contact the track surface.

Rear Spring Rate Split When racing on flatter tracks, we can often run a softer RR spring rate to help increase bite off the corners. Some teams running the conventional setups go to extremes with this spring split and end up with 25 to 50 pounds of spring rate difference. Most of the time we do not need a high amount of spring split to achieve the desired effect. I have personally set up winning cars in major series on flat tracks while using only 10-15 pounds of rear spring split.

It is very hard to balance the front and rear suspension systems when using a high amount of rear spring split, so we go with as little as possible when trying to gain bite off the corners on flatter tracks.

With conventional setups on higher-banked tracks of more than 12 degrees, we can run a rear spring split with the RR spring rate higher than the LR spring rate to help balance the front and rear suspensions. This helps control the rear roll of the car so that we can avoid raising the Panhard bar to excessively high levels.

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Improper Switch Between Installation Ratios It is common for a team to buy a new car from a different manufacturer or move to a new class in which the cars are constructed differently. What often changes is the installation ratio at the front of the car and spring base at the rear.

Suppose we have run a class using stock spring rates at the front with stock lower control arms. We decide to move to a class that uses coilover shocks and springs that are mounted differently on the lower control arms. If we had the setup figured out on the old car as far as wheel rates were concerned, we then need to duplicate those wheel rates (assuming the overall car weights remain about the same) in order to stay on track with our handling.

To do this, we need to know how to calculate the wheel rates in each car. We first work out the old wheel rates and then try different springs in the calculations until the new car has the same wheel rates. The problem is compounded if we are going from a perimeter car (symmetric from left to right) to an offset chassis.

In an offset chassis, even if we install the same spring rates on both sides in the front, we will have different wheel rates due to the different motion ratios at each wheel.

Wheel rate is determined by using the installed ratio (the position of the spring on the control arm) as well as the angle of the spring in relation to the line between the center of rotation of the ball joint and the inner pivots of the control arm. The motion ratio is the distance from the inner pivots to the center of the spring divided by the length of the control arm.

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We need to square that number. The “installed ratio squared” number is then multiplied by the square of the cosine function of the spring angle, and that answer is multiplied by the spring rate in pounds per inch. The result is the wheel rate.

If you want to run your racing buddy’s setup, make sure you know the relationship between the motion ratios and spring angles when comparing the two cars. His motion ratios and spring angles may be different from yours.

Rear Spring Installation In the rear of a solid axle suspension, the car “feels” the spring base at the top of the two springs. This is all the car knows; it’s as if the chassis were sitting on a pair of springs resting on the ground. The rear solid axle assembly is a solid base for the springs to sit on, and the car does not know, nor does it care, where the wheels are located.

Overturning moments acting through the center of gravity are affected by the resistance to roll created by the spring base width, the rear moment center height, and the rates of each spring. To change the rolling tendencies of the rear suspension, we need to look at altering the spring base (distance between the tops of the rear springs), the installed spring angle, and/or the moment center height. The narrower the spring base, the greater the tendency for the rear end to roll for a given set of springs and moment center height.

A narrow spring base can be a real problem for some types of cars. The four-link dirt Late Model cars sometimes have the springs installed at high angles, with the top of the coilover positioned well inside the framerails. This severely limits what we can do to eliminate excessive rear roll in the car.

Many teams have moved the top mounts closer to the wheel to increase the rear spring base. The swing-arm types of dirt cars have a very wide spring base by virtue of being mounted straight up, but suffer from another variable: motion ratio. The spring is mounted directly to the trailing arm, similar to the front spring mount, and that reduces the rate the car feels.

We can do a calculation similar to that of the front-wheel rate to find the effective spring rate. In most cases, we see about half the effective rate as the installed spring rate. So if we install a 200-pound spring in the RR, the car will react as if there were a 100-pound spring mounted directly to the rear end.

Stock cars and sedan touring cars based on stock dimensions (such as the Hooters Pro Cup, Craftsman Truck, Busch, and Nextel Cup Series) all suffer from a rear spring base that is too narrow. To overcome this deficiency, some teams have deviated from conventional spring rate layouts by using a stiff RR spring. For this reason, the BBSS setups tend to favor these cars. The excess spring split greatly reduces the roll tendencies of the rear suspension and causes a more balanced setup in the car, especially when a large-diameter sway bar is used.

Many more series have teams combining softer front springs with a low rear moment center (Panhard bar). These teams have worked out a solution to their balance problems associated with the narrow rear spring base. Balancing the roll tendencies of the two suspension systems is still the key objective.

The Science Behind Dirt Late Model Suspension Setup

With largely unencumbered rule sets in top tier series, suspension tuning has become a focal point for many dirt late model teams’ programs, encouraging experimentation and innovation in the pursuit of quicker lap times.

In World of Outlaws and the Lucas Oil Late Model Dirt Series racing, suspension setups have taken on increasing importance in recent years. As organizers seek to maintain parity in race fields while keeping running costs at bay through targeted mandates, it’s an aspect of tuning that’s still allowed a substantial amount of creative freedom today. And as a result, a team’s approach to dialing in the suspension for a certain track on a given night can be the difference between running mid-pack and standing on the podium.

While many popular race series have rules that provide a general path to follow, dirt late model teams still enjoy considerable leeway when it comes to suspension component combinations.

“For 99% of the teams, it’s now the most important thing,” said Marshall Fegers of QA1 Precision Products, Lakeville, Minnesota. “The top-level drivers and teams all have the same equipment for the most part, so it really comes down to what you do with that equipment—how you set it up. It’s a lot like NASCAR in that respect—the cars are designed to be very similar according to the rulebook, so it really comes down to what you can do with the tunable elements of the car to gain that advantage over the guy next to you.”

And as such, these tuning strategies have become incredibly sophisticated, leveraging technology that was exclusive to the realm of OE suppliers not so long ago. Armed with volumes of data and driver feedback, teams are aligning themselves closely with suspension component manufacturers in order to develop the solutions that can provide that competitive edge. It’s a dynamic that fosters inventive design, and it’s pushing dirt late model racing forward in a very tangible way.

“You can’t muscle your way to a win with a power advantage these days,” said Justin Cockerham of Hyperco, Rosemont, Illinois. “Suspension is the game right now.”

Painting Inside the Lines

Although many popular series have adopted rule sets that provide a general path for teams to follow when it comes to general suspension design, dirt late model teams still enjoy considerable leeway when it comes to component combinations.

“In the top-tier series, most of the rules that the teams have to work with are related to maximum ride height and droop rules based on the chassis,” Cockerham explained. “You’re also not allowed to run electronically controlled parts, and some series and classes have a limit on the number of springs you can run per corner. But there’s a lot of freedom when it comes to spring design—many racers are running stacked springs right now, or dual-rate springs, or soft, long-travel springs. And because of all the variables involved, there are virtually no two setup strategies that are alike. These racers are running at 40 or 50 race tracks around the country every season, and they’re optimizing their programs based on the data that they’re gathering. And that’s why they go faster and faster every year.”

Aaron Lambert of Penske Racing Shocks in Reading, Pennsylvania, also noted that because of the ways the rules are designed, the car’s aero kit and suspension system are intrinsically tied to one another. “Along with the droop limiter rule, every major series has a rear decklid height rule, and you’re always trying to manipulate the car so that you can pass tech inspection with the rear spoiler up as high as it can be. Aero has become a very big thing in the late model world—we have a lot of former and current NASCAR drivers and crew chiefs that are involved now, and they’re bringing over what they learned in that discipline.”

Penske Racing Shocks’ Aaron Lambert told us that air shocks are growing in popularity because of the “naturally progressive nature” of the shock’s air chamber. “You don’t see load spikes like you would with a stacked [spring] setup.”

And as these teams seek out those aero advantages, sanctioning bodies often turn to suspension restrictions to keep everything in check. “A lot of times they’ll create shock rules to negate those potential aero advantages,” said Aaron Morey of ThyssenKrupp Bilstein of America, Poway, California. “For example, there are rules that say that your shock can’t extend past a certain amount in the right front corner because teams were getting the front end on the right-hand side really high in order to bring the spoiler down low in order to pass tech, and they were out on the race track, they’d be inches above everyone else. But the great thing about dirt late model racing is that, when it comes to what’s inside the shock, just about anything goes.”

So although the rule sets confine tuning to a general set of parameters, there’s a lot of room for creativity within that sandbox. “Years ago, we would have only run a single spring per corner,” said Jason Young of Öhlins USA, Hendersonville, North Carolina. “Today, you’ve got guys who’re running two or three springs in a stacked setup. Bump rubbers are a bigger player in the market these days as well, along with bump springs and bellow washers. There’s a ton of different options out there now.”

Shocks are often considered “black magic” by many, so few dirt late model teams work on them, said one source. Instead, many teams have developed relationships with shock manufacturers and work with them to get the results they want on the track.

Lambert told us that air shocks are seeing an upswing in popularity, too. “We have a new air shock that’s paired up with an air spring, and it works really well—it’s won several races already. With that design, we’re able to manipulate the spring curve in ways that we wouldn’t really be able to otherwise—it’s a really big advantage. A lot of these guys are running two stacked springs in parallel on the right front with a bump stop to create a spring curve that yields different spring rates based on where the suspension travel is at a given moment to create a progressive rate system. But the problem with that is when the suspension crosses over from one spring to the next as it’s compressed, you will inherently see a load spike in the suspension, and that load spike transfers to the tires. Any time a tire sees a load spike, there’s going to be a loss of grip. But an air chamber is naturally progressive as it is compressed, so you don’t see those load spikes like you would with a stacked setup.”

Ditching the Guessing Game

With so many different combinations available and a rule set that encourages experimentation, you might expect each team’s suspension tuning strategy is largely based on seat-of-the-pants driver feedback and the associated lap times delivered. But gone are the days of lengthy trial and error with a hunch and an arsenal of parts. Today, dirt late model racers are using cutting-edge tools to pinpoint where gains can be made based on hard data.

“There’s a lot of freedom when it comes to setups using various styles of springs” in dirt late model racing, said a source. “Many racers are running stacked springs (pictured), or dual-rate springs, or soft, long-travel springs, bump springs or combinations of all the forementioned. With the variations of chassis designs, damper tunes and driver preferences, rarely do you see the exact same spring packages between two competing cars within the same series.” Photo courtesy of Hyperco.

“There’s been kind of a revolution in late model setups over the past few years,” said Fegers. “Before 2015, to set the cars up we would put them on four-corner digital scales and get our corner weights and ride heights where we want them. But after that, ‘smash machines’ became much more prevalent. With these machines you can compress a shock with a spring on it to a given center-to-center measurement on the shock mounts, and it will tell you a spring force with a digital readout. The smash machines have led to a major transition in how we talk about setups and what we pay attention to in those setups. Now, not only do we know what the spring force is at static height, we can also look at the dynamic height it will be at when the car is racing on track. That has really changed the game—we don’t really worry about our ride heights as much, and we care a lot more about the spring force at the height that the car is seeing at speed. We can tune it to make sure the bumper isn’t going to dig into the track, or the right-rear doesn’t compress so far that it starts to pull the left front corner off the ground. It’s allowed teams to develop a baseline and make quick, drastic changes as needed for a given track.”

Cockerham pointed out that, for teams that want to run up front, understanding how to effectively use this technology has become obligatory for dirt late model racers.

“Every single top-level contender has a spring smasher in their trailer, and they’re constantly testing and looking at travel and load numbers to understand how the changes are affecting the car. Springs are the cheapest form of data acquisition on the car—if you’re able to measure your spring’s travel at a very precise and accurate level, you can get a world of useful information about the dynamic forces of your race car.”

Conducting the Symphony

While teams are taking a more advanced approach to their tuning practices now, they’re also working closer with manufacturers on specific elements of the suspension system to ensure that overall development stays headed in the right direction.

“Four or five years ago, if you walked around the paddock at a late model race you would have only seen Integra and Penske shocks,” said Lambert. “Now we’re seeing big pushes from companies like Bilstein and Fox, so that’s been really good for the racers, and all of the guys who’re running the fast cars in these top series are tied in with a shock manufacturer. Shocks are still considered black magic in dirt late models—not a lot of teams work on them on their own. Instead, they’ll explain to their shock manufacturer what the car is doing and what they want it to do, and the manufacturer builds shocks around that feedback to produce those results.”

Race organizers seek to maintain parity in race fields, creating a situation where top-level drivers and teams have similar equipment. Under those conditions, “it really comes down to what you can do with the tunable elements of the car to gain that advantage over the guy next to you,” said one source.

It speaks to the nature of the suspension systems in general—a complex collection of components working in concert, where changes in one area often affect behavior in another. “The teams deliver the feedback to our engineers and we provide the solutions,” Morey said. “Sometimes that’s exclusively through shocks, but sometimes it’s a combination of shocks and other suspension parts.”

Even with these advanced systems, analyzing suspension performance based on data acquisition can still be a tricky proposition for teams, Öhlins’ Christer Lööw pointed out. “You have to have a lot of experience and know what you’re looking for. There’s no meter that tells you that the suspension is getting better or worse. But the clues are in there,” he said.

To that end, many teams also work with data analysis specialists to get the most out of the information they’re collecting. “On a night-to-night basis it’s often handled by the teams,” Fegers said. “A crew chief will look at the track and look at the car and know what changes they need to make so the car will run faster. But many teams will also bring in engineering support for test days to help dial in the car based on the data.”

And it all points the way toward more informed teams with increasingly faster cars in the future. “As we learn more, I think you’ll probably start to see more instances where the suspension is reacting to inputs that are coming from places other than the wheel,” Lambert said. “If the wheel is moving, other parts of the car are moving as well, and that has an impact on the suspension’s behavior. At the end of the day, if you can do things that can provide more mechanical grip, it’s going to give you an advantage.”



Öhlins USA

Penske Racing Shocks


ThyssenKrupp Bilstein of America

키워드에 대한 정보 soft left rear spring dirt late model

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