Know how to drive?.....Now learn the other end of a race car

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The "ULTIMATE" Racing Car Chassis Setup Guide and Tutorial.
How to Use this Guide
The information in this guide may change without notice. I've tried to make this guide simple to use & easy to understand. By clicking on the contents you will be taken directly to the info your looking for. Throughout this guide I will use the abbreviations RF,RR,LF,LR. These stand for right front, right rear, left front, & left rear respectively. Whenever I bring up the left or side of the car I'm talking about the drivers side. The right side of the car is the passenger side. All left & right references are viewed from the drivers position. By holding your mouse over a setup option for a few seconds in the sim, you will be given a brief description of how that adjustment works or what it affects. Right clicking an option brings up the description right away.

One last thing I must mention before turning the wrenches. It is important to understand that for every adjustment you attempt, it may not produce the desired results right away as mentioned below. You may have other chassis adjustments that are not quite right masking the problems your trying to adjust for. Because of this factor, you may not see as drastic a change in your adjustments after just one change. You may have to readjust another chassis component to so call "free" up your original adjustment. If you feel your setup is close, yet seems to be lacking that one minor adjustment, it may be more involved that just adjusting one more component. You may have to "undo" another few adjustments elsewhere then go back to your original adjustment to get it just right. For every action you take, there will be a counteraction that may not appear at first to be in the best interest of your setup. There may be times when you may have to take two steps back to gain one step forward. Because of this, chassis adjustments can become frustrating to figure out. It isn't easy, as many WC teams find out on any given Sunday. Perseverance & patience are required when playing this chassis setup game.

Where to Begin
Before attempting any chassis adjustments it is important for you as a driver to know & understand what your car is doing on the track. The only way to understand how your car is reacting is through seat time. The more laps you turn, or practice you get; the better off you will be in deciding what your trouble points are on the track.

Learn how to hit the same line lap after lap with the default setups packaged with NASCAR Racing before attempting any other adjustments. The biggest mistake rookie drivers make, are trying to adjust a chassis for what they believe is an ill handling car. I get so many emails from drivers that think the default easy, intermediate or fast setups that come with the sim are terrible because they cannot drive them. You must become comfortable with these default setups before you should even look into tinkering with any adjustments in the garage. Begin with the easy setup, then graduate to the intermediate setup and lastly the fast setup. Only when you can run clean consistent laps with the easy setup, should you move up to the intermediate setup. The same goes with the intermediate setup before graduating to the fast. Only when you can run competitively with the fast setup against the AI at 97% without spinning out, should you attempt to make any adjustments in the garage. There are nothing wrong with the default setups in NASCAR Racing. If you cannot drive them properly it is because you simply do not have enough seat time and or experience.

I can't stress enough the importance of adjusting only ONE component at a time. Making more than one change is nonproductive because you won't be able to determine what change made the car better or worse. Be sure to have plenty of paper & pencil on hand. It is critical to take notes after every adjustment you make. With all the adjustments available to make, it's real easy to forget what adjustment you made 3 practice sessions ago. Record keeping is important. If you do go the wrong way with an adjustment you can always set it back to where it was before making the change by simply referring back to your notes. By tracking & logging information, it also allows you to refer back to them to see how you progressed to cure your handling problem. These notes could be useful for setups at tracks with similar configurations which can turn out to be a real time saver. By keeping track of adjustments, you will be able to refer back to your notes to see what worked & what didn't. This will help you decide what to adjust if a similar situation arises at another track.

Weather changes are another reason that record keeping becomes a must. The changes in the handling of your car in various weather conditions seems a lot more pronounced that previous releases. What works fine at 70 degrees & no wind may not be worth a damn at 90 degrees with a 20 mph wind. This is especially true for gearing and tape. In general, you’ll want to loosen the car up some as the temperatures go up and tighten the chassis some as it gets colder. Keeping good records will ease your efforts & time over the long run.

I've included two setup sheets with this guide to help track your chassis adjustments. One is a chassis setup sheet for you to track all of your chassis settings. The second is a tire temperature sheet for logging tire temperature after practice sessions. Simply print as many of these sheets as you like to help aid in your record management. Here is another helpful GearRatios101 sheet tool also.

One of the more overlooked aspects of chassis setup is the driver himself. More so than ever it's critical for drivers to run the same line over & over when practicing & adjusting. If you're entering the track low in turn 1 & the car is loose, don't make an adjustment then start entering the same corner in the middle. This again is nonproductive & you won't know if it's your line into the corner that has helped or made your condition worse or if it's the adjustment itself. Driver consistency is very important when trying to determine how a car is reacting throughout a corner. Smooth & gradual throttle, brake, & steering inputs are required. Gone are the days of barreling into a corner, slamming on the brakes, & cranking the wheel hard left.

As a driver it's very easy to mislead yourself into believing how your car is reacting through a corner. If your loose going into a corner then push in the middle & once again get loose exiting, it could very well be your driving habits. I see many drivers getting loose into the corners. When this situation occurs, the obvious reaction is to brake & turn into the spin in hopes of catching the back of the car. If you do manage to correct it, chances are you'll have a push in the middle as the car sets & grabs from you turning right in an effort to save it from corner entry. Now in an effort to get back low into the racing-groove, you jerk the wheel hard left applying throttle causing yourself to be loose. You may think your setup is all out to lunch when the fact of the matter is that it's you causing two thirds of the problem all because your loose entering the turn. You may still have cornering problems in the middle & exiting, but because of your looseness going in, you yourself could be making the rest of the corner a problem when in fact it really isn't.

Because of this, it is important to divide each corner into 3 sections. The entry, middle, & exit. Each section of the turn will be effected by how you negotiated the previous section. Corner entry is where you begin your chassis adjustments. If you can't get into a corner, don't bother adjusting for the rest of the corner. Don't mislead yourself into believing the car is doing something that it isn't. In the above example you must take care of the loose condition entering the corner before you setup for the rest of the corner. Once your happy with the setup entering the corner, work on how the car feels in the middle. Only after you have a neutral handling car entering the corner & through the middle do you attempt to work on adjustments exiting the turn. Many times by simply curing your corner entry problems, you'll cure your middle or exiting problems. This is because you won't be making corrections to either loosen or tighten up the car based on corner entry problems.

If you can always remember to divide each corner into sections, & work on entry before worrying about the rest of the corner, it should go along way towards simplifying the whole setup process. Be consistent & smooth with your driving inputs.

CHASSIS ADJUSTMENTS


Camber
Camber is the inward or outward tilt of the wheel at the top of the tire. Negative camber is the tilt of the top of the tire towards the center of the vehicle.
Positive camber is the tilt of the top of the tire away from the center of the vehicle. Camber adjustments are utilized to help maintain the maximum grip allowable from the surface of the tire through the corners of the track. Proper camber adjustments are very critical for achieving maximum cornering speeds.


Proper camber adjustments are achieved by reading tire temperatures. Read the section on Tire Temperatures for the proper way to decipher what your tires/camber are telling you. In a WC car you are allowed camber adjustments on all 4 tires. In NASCAR Racing we are allowed a wide range of adjustment for the front tires. +5 is the most positive camber allowed, while -5 is the most negative camber allowed. In the rear we are only allowed adjustments of +1.8 through -1.8.


Contact Patch
When camber is set correctly it allows the entire surface of the tire to adhere to the track thus maximizing the use of the tire contact patch when taking a corner at high speed. On all tracks except road courses you'll want to run with negative camber on the right front & positive camber on the left front. Running camber as such will create part of the pull to left that will help the car get through the corner easier. The more excessive the cambers the greater the pull can be. Running excessive amounts of camber will cause premature tire wear due to the fact that the tires aren't running on the full contact patch of the racing tire.

As a general rule, the flatter or slower the track the more camber you'll need on both front tires. More positive camber on the left front & more negative camber on the right front would be required at a track like Martinsville over a high speed high banked track like Talladega. Another factor in determining camber is body roll. The more the car "rolls" over through a corner the more negative camber you will need in the RF. Body roll is determined by how stiff your springs & or sway bars are. The stiffer the springs, the less body roll. The less body roll, the less amount of negative camber required in the RF.

Rear camber is not as critical as front camber due to the fact that the rear end is solid axle. The same theory holds true though as you might want negative camber on the RR & positive camber on the LR on an oval track. On a flatter track you may not need any camber in the rear. Stagger built into the Goodyear tires will naturally create some negative camber in the RR & positive in the LR as is.

When competing on a road course like Watkins Glen or Sears Point or any track where your making both left & right handed turns you'll need to "square" up your camber or make it equally negative on both sides.

When all is said & done, knowing how to read & understand tire temperatures will be the determining factor in how much camber to set in your wheels. In fact it's the only way to properly adjust for correct amounts of camber. Since you must constantly monitor tire temperatures you will always be readjusting camber (at least in the front). Just when you think you have your tire temperatures & camber perfect, you'll change a spring or tire psi to find more speed, or the weather will be different forcing you to make some adjustments elsewhere. All that hard work you spent on achieving those perfect temperatures will have to be thrown out the window & the whole process begins once again.

Keep in mind that adjusting one part of the car & not readjusting camber could be throwing off your original adjustment. Let's just say for example that you didn't take tire temperatures after changing the RF spring & running another 20 laps. Your times are slower after the spring change & you give up on that spring change because it made you slower. Maybe it wasn't the spring change that made you slower it was your camber being off that made you slower. Readjust the camber after running 20 laps with that spring change then decide if that was really the wrong way to go. Did you go faster after making the spring change? No. Did you go faster after making the spring change & camber change? Ah there ya go . Take constant notes of each & every adjustment you make. If it doesn't work, you'll at least know how to set it back to where is was before you started.

Here is a synopsis of how cambers effect the handling of the chassis:

More negative RF camber allows the car to turn into a corner quicker & will loosen up the chassis.

Less negative RF camber takes away some of the pull to the left. The car won't turn in as quick into a corner & will tend to tighten the chassis.

More negative LF camber will reduce the pull to the left while tightening the chassis from the middle out.

More positive LF camber will increase the pull to the left & allow the car to turn into a corner quicker loosening the chassis.

More positive camber in the RR will loosen the car from the middle out.

More negative camber in the LR will loosen the chassis entering a corner.

Caster

Caster is the leaning forward or back of the tire at the top of the wheel. Do not confuse this with camber which is the inward or outward tilt of the wheel at the top. Positive caster is when the wheel is tilted back toward the rear of the vehicle. Negative caster is when the wheel is tilted forward toward the front of the vehicle.

Caster is used to provide directional steering stability. When thinking of caster, think of a tool box, TV stand, chair, or anything else that has 4 wheels on it that swivel to help you move it across the floor. When you push an object like this across the floor you'll notice that the wheels will swivel back allowing you to push forward with ease. This is positive caster. Now take those 4 swivel wheels & turn them forward 180 degrees. This is negative caster. I'm sure you know how difficult it is to push something with the wheels in this forward or negative position. Besides being difficult to push, it also has a tendency to take off in an unwanted direction until the casters spin in a positive direction. For the same reasons we want our chair to slide across the floor with ease, we want our race car to do the same. When setting your chassis you'll want to tip the top of the wheels back adding positive caster to provide you with that straight ahead directional stability. There are NO circumstances where negative caster is preferred, even though adjustment range in NASCAR Racing is from -2.0 through +6.0.

Proper caster adjustments will vary with each track & individual driver as well as the steering device you maybe using. (i.e. force feedback) The more positive caster the more feedback you will feel as a driver. More caster can also provide a more difficult steering effort, especially with a force feedback wheel. More positive caster will also give you a better feel for the car. More caster will allow you to make better decisions on the track about how the car is handling.

So why not crank the caster positive as far as it will go? Because too much positive caster also has it's drawbacks. When you turn a car left with positive caster the LF rises while the RF drops. This changes the weight on all 4 corners of the car. In effect you're taking cross weight out of the car the more you turn the wheel. The more positive the caster, the more cross weight there is being removed. The more cross weight you remove the looser the car will get.

In general, you'll want to run higher positive caster settings on a short track with tight corners, over a larger track with long, wide sweeping corners & long straight-aways. +4 to +5 on the RF isn't uncommon for a track like Martinsville. For Michigan or California a setting of +2 or +3 would be preferred. Higher caster settings allow you to ‘catch’ power slides on exit a little bit easier as well.

Another element that must be considered is the caster split or caster stagger as I like to call it. Caster stagger is simply using different settings on the LF wheel than the RF. When caster settings are different, your steering will tend to pull toward the side with the least amount of caster. On tracks where your only turning left, you would want a higher positive caster setting on the RF than the LF. This more positive caster on the RF will make the car pull to the left entering the turns, which is the preferred setup for entering the corners. The higher the caster stagger you run the easier the car will turn itself into the corner. Higher stagger will also take some feel out of the car & also force you to hold your wheel to the right down a straightaway.

Caster stagger will also affect braking. If you run too much stagger at tracks that require heavy braking such as Martinsville or the road courses, you may have to add brake bias. Although a better trade-off would be just to even up the caster allowing you to brake harder without causing the car to pull to the side with the least amount of caster.

Caster stagger is NOT the only adjustment that will give you that pull to the left. Many other factors must also be considered. Camber settings, weight balance, tire stagger, tire psi, & track banking also plays an important role. Many newcomers will be uncomfortable with the pull to the left & many may even think that there wheel won't calibrate properly. This pull to the left is normal & is the preferred setup to assist drivers when entering the corners with ease. Most caster stagger settings will be between 2 & 3 degrees. In other words, if you ran 1 degree positive on the LF, you would run positive 3 or 4 on the RF. In general, tracks that are small & have tight corners will require a higher caster split to help you turn into a corner better.

Simulating the pull that a stock car gets in a game is going to yield different results for different types of controllers. To add to this variation, the Linearity setting you choose in setting up your controller, in combination with the steering ratio you choose within the setup is going to contribute in making the pull feel different from user to user. On any given controller, setup the Linearity towards the Non Linear side (say 10%) You will notice the need to use a lot more counter steering on the straight than somebody using 90% Linearity with the exact same setup.

Do you see real drivers using counter steering down the straights? No, because they can center the wheel on the steering shaft. Is the pull still there for them? Yes. You can get your controller to center on the straights by how you calibrate it, get rid of it entirely if you like. Will you still feel the pull? No, why? because the pull you're feeling is from the tension on the springs, bungee, or whatever your controller uses to center itself. Your controller isn't hooked up to the suspension of a stock car, so you're not going to be able to feel the dynamic pull that the suspension creates. Furthermore, your steering wheel doesn't have the range of motion as a real car. At best you're probably getting from 240 to 270 degrees of motion, and much less on a Joystick (maybe 90 degrees if you're lucky?) A real car has what, maybe 3 to 4 full rotations from lock to lock? With this in mind the game has to have Steering Ratio values that can compensate for the lack of true lock-to-lock movement. The differences in degrees of lock to lock motion between a joystick and a wheel is why the Linearity setting makes such a big difference, it has to in order to make all types of controllers usable. You just need to find the setting that is comfortable to you.

One thing to remember in NASCAR Racing, a setting of 32:1 is going to require MORE steering movement than a setting of 15:1, which would be more sensitive to steering input.

Caster synopsis:

More positive caster will loosen the chassis the more the wheel is turned through a corner.

More positive caster will allow you to catch slides on exit a little easier.

Caster adjustments are better felt through a force feedback wheel.

The car will pull to the side with the lower amount of positive caster.

The higher the caster stagger, the easier the car will turn into a corner.

The higher the caster stagger, the easier the car will break loose braking into a corner.

The higher the caster stagger, the less steering effort required. This will tend to give you a loose feeling upon corner entry.

Differential Ratio

The differential is a gear assembly in the rear end whose purpose is to distribute torque to the rear wheels for traction. In NASCAR Racing we have the ability to change these gears allowing us to run different ratios for different size tracks. This adjustment can be accessed by clicking the drivetrain/aero tab on the garage screen.

The ratio expresses the number of turns required by the pinion (which is attached to the output shaft of the transmission) to turn the drive axle one revolution, i.e. 2.857 means the pinion must turn 2.86 times to turn the drive axle once. A higher number (6.556) means a lower (or shorter) gear. Short gearing gives quicker acceleration, but because the engine must turn faster, fuel mileage and top speed are lower. Tall gears give smoother acceleration and higher top speed, at the expense of quick acceleration.

We are allowed to choose from no less than 49 different ratios with an adjustment range from as low as 2.857 to as high as 6.556. The differential ratio you will need is different for every track you compete at & is the most common gear changed on a WC race car. When you change the differential ratio, you change all the final drive ratios together proportionally.

On short tracks you will want to choose a higher differential ratio because quicker acceleration will be a must at tracks where speeds are not as high. At super speedways you'll want a smaller ratio for top speed since quick acceleration is not necessary on a track where you're at full throttle most of the time. The most important factor when considering what ratio to use is that you don't choose a ratio that is too high. Too high a differential ratio will result in running higher rpms. If, by the time you reach the end of a straightaway, you're running higher than 9000 rpms. you risk having your rev limiter kick in. This will result in a loss of torque & thus a loss of speed. The rev limiter is used to prevent us from running too high an rpm, which could result in a blown engine. You must watch your tach when changing gear ratios. If you're running too high an rpm you will also notice it through the sound of your engine as a "missing" sound.

As you adjust other chassis components, you will most likely find yourself having to change your differential ratio. As you find more speed through the corners, you'll eventually find yourself on the throttle quicker. Since you're on the throttle sooner you will be running a higher rpm towards the end of a straightaway. This is likely going to force you to make a differential change.

Differential synopsis:

The higher the ratio/number (6.556) the higher the rpms. Provides quicker acceleration, but slower top speeds.

The lower the ratio/number (2.857) the lower the rpms. Provides slower acceleration, but higher top speeds.

Final Drive Ratios
The final drive ratios can be viewed by clicking the drivetrain/aero tab on the garage screen. This is a non-adjustable option that is basically used for comparison purposes. The final drive ratio represents the number of engine revolutions to rear wheel revolutions. The final drive ratios can be viewed for all four gears. These 4 ratios change automatically whenever the differential ratio is changed & will change individually per gear whenever a transmission ratio is changed.

Like the differential & transmission ratios, the final drive ratios are read in the same manner. A higher number means a lower (or shorter) gear. Short gearing gives quicker acceleration, but because the engine must turn faster, fuel mileage and top speed are lower. Tall gears give smoother acceleration and higher top speed, at the expense of quick acceleration.

Your highest final drive ratio will be in 1st gear & should get smaller as you move through the gears. Your final drive ratio will be the same as your differential ratio. Unless your at a track that requires a lot of shifting, the final drive ratio will not be that important & is only used to compare how your ratios change through the gears after attempting a differential or single transmission ratio change.

Final Drive synopsis:

The higher the ratio/number the higher the rpms. Provides quicker acceleration, but slower top speeds.

The lower the ratio/number the lower the rpms. Provides slower acceleration, but higher top speeds.


Front Bias
The Front bias can be adjusted by clicking the weight bias tab on the garage screen. Front bias is the amount of weight on the front of the chassis as compared to the rear of the chassis. Front bias is determined by placing lead weight at various points as low as possible in the chassis. Sliding this weight forward gives you more front weight or bias. Sliding this weight towards the back of the car decreases front bias & increases rear weight or bias.

The most front bias were allowed is 54.2% (1950 lbs.) The least amount is 45.8% (1650 lbs.) Finding the correct amount of front bias depends on the track, banking, spring rates, frame heights & gearing. Generally speaking, the flatter the track, the more front bias required. The higher the banking the less front bias required. This is because the higher banked tracks require less braking which in turn means less weight is being transferred to the front of the vehicle. Less front bias or more rear bias would be preferred at a track like Talladega.

A slower track that requires shorter gear ratios, will also require less front bias. This is due to the problem of wheel spin that can occur during acceleration. You would rather have less front bias or more rear bias to help transfer weight to the rear quicker to avoid wheel spin. Just the opposite would be true when a higher gear ratio is required.

The more front bias you run the tighter the chassis will be, especially at mid turn & beyond. The less front bias you run the looser the chassis will be. A front bias of 50 - 51% would be a good starting point for many tracks. A track that is small & requires heavy braking may only require a front bias of 48 or 49%. Anything below 48% or higher than 51% isn't realistic in a real cup car, but can still be effective given different spring rates, sway bars & frame heights. Experimentation once again with all these variables will be the only way to correctly determine the proper front weight bias given the various circumstances.

Another factor that must be considered when dealing with front bias is Fuel. As fuel is burned, your rear weight distribution is lowered. You will lose approximately 1% of rear weight per every 5 gallons burned. This means that by the end of a full fuel run you'll lose over 4% rear weight. With less fuel & less rear weight, the car will have a tendency to tighten up as fuel diminishes. Although your not directly changing your front bias, you will be affecting the amount of weight that is being transferred as fuel is burned. This will result in an ever changing car as fuel dissipates.

Front Bias synopsis:

More front bias will tighten the chassis.

Less front bias will loosen the chassis.


Front Brake Bias

Many people believe that the brakes in a racecar are used for nothing more than slowing or stopping the car. Nothing could be further from the truth. Properly adjusted brakes can improve lap times by allowing you to get into a corner better. All WC drivers have an adjustment that allows them to control how much brake pressure is allocated towards the front & rear wheels. Front brake bias allows us that same exact adjustment.

When entering a corner 60 to 80% of the weight is transferred to the front of the car. The exact amount depends on the speed of the car, track, corner, & how much brake is applied upon entry. Because of these varying factors more or less front brake needs to be "dialed" into the car. Between the front & rear master cylinders is a balance bar that can be adjusted to allow more or less brake pressure to be applied towards the front when the brake pedal is pushed.

Within the sim we are allowed to set the front brake bias to as little as 50% to as high as 90%. Due to the rear brakes having larger calipers, at about 65%, the brake pressure is being applied equally to both the front & rear tires when the brake pedal is depressed. Since so much weight is being transferred to the front upon entry into a corner, a setting of 50% would probably be way to low. A setting of 67% or higher would be more desirable for a short track due to weight transfer.

The correct front brake bias setting depends on your driving style & how hard or how much you use your brakes getting into a corner. Since this will vary with each corner at each track, it is important to find the right balance as not to upset the chassis when you apply the brakes while cornering. It is important not to confuse a loose or tight condition upon entry with a front brake bias problem IF your problem doesn't occur when using the brakes. On the other hand, your chassis may not be tight or loose on entry, but because you have the incorrect front brake bias set into the chassis, you're creating a problem when using the brakes. It is real easy to mask or create an I'll handling car getting into a corner by making a front brake bias adjustment.

The more front brake bias (higher the number) you have set in the car the tighter the car will be on entry. The lower the number the looser the chassis will be. This tight or loose condition from front brake bias will only occur while your on the brakes entering the turn. If your loose entering a corner & are not using the brakes, then you do not have a front brake bias problem. Some may try to add front brake bias to tighten up the chassis going in, but unless your using the brakes going in, changing front brake bias will be useless. Plus the fact remains that you are only masking the problem of the loose condition by trying to compensate with a brake adjustment. You might want to adjust the chassis elsewhere to tighten the car up on entry.

So how do you know when you have the correct amount of front brake bias? I believe the correct brake bias is determined by how the chassis reacts when hitting the brakes hard going into a corner without locking them up. Enter a corner without jerking the wheel hard left & apply 3/4 brakes or as much as possible before lockup occurs. It is important not to steer any more than is necessary. Any added steering inputs can throw off your results due to the added weight transfer that occurs while turning. How did the chassis react? If your back end wants to come around on you, you have too much rear brake & need to add more front brake bias. If your car pushes towards the wall you have too much front brake & need more rear brake. When you can perform this test & the chassis holds a straight line you know you have the proper amount of front brake set into the chassis. You’ll probably also want to make sure that you’re not using any caster stagger during this test. Once you have the brake bias the way you want it, you can go back and work on the compromise between caster stagger needed for turn-in but not so much it causes you to use to much front brake bias.

Front Brake Bias synopsis:

More front brake bias will tighten the chassis entering a corner under braking.

Less front brake bias will loosen the chassis entering a corner under braking.

Front Roll Couple


Whenever you turn, there is going to be some body roll. Body roll has to be handled by the suspension system so the tires won’t break traction. Since Cup cars use independent suspension, the front and rear of the chassis handle their share of body roll separately as it passes through the front and rear roll centers.

Roll couple percentage is how much body roll is distributed between the front and the rear suspension systems. Since we know the stiffest end of the car will slide first, roll couple provides a pretty good indication of whether the chassis is going to be loose or tight. If the front slides first, the chassis is tight and if the rear slides first the chassis is loose.

If you have an 80% roll couple, 80% of the transferred weight transfers between the left front and right front wheels while only 20% is being transferred at the rear.

Figuring out roll couple is a complex formula that includes roll rate, track width, spring rate, sway bar lengths and thickness, anti roll lever lengths and rates, and tire pressures. In NASCAR Racing, all of this is done for you and the roll couple is determined by adjusting the front and rear springs and sway bars. Increasing the front springs and swaybars as well as decreasing the rear springs and swaybars will increase roll couple while doing exactly the opposite will decrease roll couple.

In general, front roll couple is somewhere between 70% and 80% for oval tracks. The higher the front percentage number, the more understeer (pushing) there is in a chassis. Conversely, the less front roll couple, the more oversteer (loose). The reason the front roll couple percentage is so much higher than the rear roll couple is because most of the weight transfer from inside to outside during cornering should be led by the front(or non driving) wheels.

There is also a direct correlation of weight distribution and roll couple. Typically, as you move weight forward in the car, the less amount of front roll couple is needed. As you move weight back more front roll couple would be needed. Adjusting roll couple should be done before adjusting wedge in regards to tightening or loosing the chassis. It is possible that taking out wedge could have a negative impact on right front tire wear as more dynamic weight may be distributed to the right front from the heavier load that was jacked (static negative wedge) to the left front and right rear.

Roll Couple synopsis:

A typical roll couple percentage at the speedways would be in the lower 70% range moving towards 80% as the weight goes back for shorter tracks.

Adjust roll couple before adjusting wedge to tighten or loosen the chassis.

Increasing the front springs and swaybars and/or decreasing the rear spring and swaybars increases the front roll couple percentage.

Decreasing the front springs and swaybars and/or increasing the rear springs and swaybars decreases the front roll couple percentage.


Front Sway Bar
A sway bar is also known as an anti-roll bar or stabilizer bar. The purpose of a sway bar is to control body roll through a corner. This is done with a bar that connects to both front lower a frames. Without getting to technical, a sway bar acts as a third spring to help balance out weight transfer during cornering. There are a number of ways to adjust sway bars, but within the sim we are only allowed to adjust them one way, & that is through the size of the sway bar itself.

Within NASCAR Racing we are allowed a total of 12 different choices for the front sway bar. The sway bar is measured by the thickness or diameter of the bar. The thicker the bar the stiffer the bar. Here are the diameter choices of the bar:

0.000" 0
0.875" 7/8
0.938" 15/16
1.000" 1
1.063" 1 1/16
1.125" 1 1/8
1.188" 1 3/16
1.250" 1 1/4
1.313" 1 5/16
1.375" 1 3/8
1.438" 1/ 7/16
1.500" 1 1/2



By changing the diameter of the bar we are able to adjust the amount of roll couple or weight transfer that occurs at the front of the car. Generally speaking, the larger the bar the less the body roll up front. The less the body roll the tighter the car becomes. Therefore the smaller the bar, the more body roll & the looser the car becomes. Fine tuning with sway bars is an easy way to compensate for roll couple or body roll.

Front Sway Bar synopsis:

The larger the bar the tighter the chassis.

The smaller the bar the looser the chassis.


Front Toe Out

Front toe out is when the tires are farther apart in the front of the tire than the back. Toe in would be just the opposite. Front toe out is utilized to help prevent tire scrub while cornering. Within the sim we are allowed adjustments that range from -0.200 of toe in through 0.200 of toe out. Under no circumstances would you want a toe in condition. The majority of setups usually require a setting of less than 0.125 out. I wouldn't run anything less than .000 & no more than 0.175 out max. at any track within the sim.

As a general rule, the smaller the track & tighter the turns, the more toe out you may need. Larger radius tracks with long corners would require less toe out. More toe out will help the front end stick entering a corner. Running too much toe out will scrub off speed down the straightaway & create an Understeer condition. A car will run faster with the toe straight. By monitoring tire temperatures you can tell if you have a toe problem with the chassis. Excessive toe out would show higher temperatures on the insides of both front tires. Excessive toe in would show higher temperatures in the outsides of both front tires. Front toe in or out will cause the same feelings to a chassis as excessive amounts of camber & caster, albeit to a much lesser degree.

Front toe out isn't an adjustment that has to be changed or monitored as often as camber. Start with an adjustment of 0.050 & you will be close. Adjust the toe slightly only when the rest of the chassis is real close to being correct.

Front Toe Out synopsis:

Excessive front toe out will make a car turn slower into a corner, & cause a tight condition.

Excessive front toe in will make a car turn into a corner quicker, & may create a loose condition.


Fuel Level
Your WC race car comes equipped with a 22 gallon fuel cell. Your allowed to adjust the fuels levels from 1 gallon to 22 gallons for practice sessions only. All races as well as qualifying must begin with a full 22 gallons in the tank. Gone are the days of deciding how much fuel you want to add during a pit stop. We are now faced with 5 options. You are allowed to take on a splash of fuel as well as 1/2, 1, 1 1/2, or 2 cans. A splash of fuel will give you 2-3 gallons. 1/2 can gives you 5-6 gallons. 1 can equals 11-12 gallons, 1 1/2 cans will give you 17-18 gallons. 2 cans will fill your tank with 22 gallons. These options can be selected by hitting the left or right arrows on your keyboard after hitting F3. The less fuel your carrying the faster your car should be. This of course depends on tire condition.
The important thing to understand about fuel, is how it effects the handling of your car as it is burned. 1 gallon of fuel weighs 6.17 pounds. Multiply that times 22 gallons and you have an extra 135.74 pounds your carrying in the back of the car behind the rear axle during qualifying & at the beginning of a race. As fuel is burned, your rear weight distribution is lowered. You will lose approximately 1% of rear weight per every 5 gallons burned. This means that by the end of a full fuel run you'll lose over 4% rear weight. With less fuel & less rear weight, the car will have a tendency to tighten up as fuel diminishes. This is important to remember when taking on less fuel late in a race. If your setting your chassis based on using a full 22 gallons, you may think that by taking less fuel that you will be quicker. Depending on your setup that might not be the case.

The best solution is to practice your setup with different fuel levels to see how it performs. It's also possible to make a wedge or track bar adjustment in the pits to compensate for how your will react with less fuel.

Fuel Level synopsis:

Less fuel equals faster speeds.

The less fuel in the tank the tighter the chassis will become.

Splash = 2-3 gallons, 1/2 can = 5-6 gallons, 1 can = 11-12 gallons, 1 1/2 cans = 17-18 gallons, 2 cans = full tank.


Grill Tape
The grill tape option is located under the drivetrain/aero tab within the garage menu. Grill tape is nothing more than duct tape. This tape is applied to the front bumper & air dam of the car covering the openings for air flow to the various components that are cooled through the force of air. These components include the radiator, oil/transmission coolers, & brakes. The only component were worried about is the radiator.

Within the sim we are allowed to run as little as no tape all the way up to 100% which covers every opening in the front grill. The amount of tape that can be added, can be done in 5% increments. The more tape you apply the hotter your engine will run. This will be reflected on your water temperature & oil gauges & or warning lights on your dash board. Running excessive amounts of tape for a long period of time will result in engine failure. So why put any tape at all on the the front end?

Taping off the openings in the front of the car reduce drag & increases speed. Instead of air going through the car, air is being forced around the car. This places more downforce on the front end. More downforce will make the front of the car turn into the corner quicker. Excessive amounts of tape can cause too much downforce making the rear of the car lite creating a loose condition. Weather is another factor you must consider when deciding how much grill tape to use. It stands to reason the hotter the day, the higher your water temperature will be. Therefore with the warmer weather you'll find yourself having to run less grill tape to allow more air flow through the front of the car. In other words, running the same amount of grill tape on the same track in 50 degree weather may cause an overheating or engine failure problem with the weather being 85 degrees. Be sure to keep an eye on your gauges, or you may find yourself pitting to remove some of that tape.

The secret here is to find the best trade off between speed & handling. Try to get away with as much tape as possible on superspeedways without causing excessive water temperature. More tape will decrease lap times. If you discover you can get away with running more tape, but become to loose, adjust for the looseness elsewhere.

Grill Tape synopsis:

Higher tape % will increase speeds.

Higher tape % equals higher water temperatures.

Higher tape % will loosen the chassis.

The hotter the weather the less tape you can use.

Tape causes aerodynamic changes that have very little affect at speeds less than 140 MPH.


Left Bias
The left bias can be adjusted by clicking the weight bias tab on the garage screen. Left bias simply means how much weight is on the left side of the car compared to the right side. Between all the weight adjustments allowed, this one is the easiest to figure out.

When you enter a corner on an oval track, you hit the brakes & turn left. Weight will naturally go forward & to the right upon corner entry. Because of this you'll want to start with weight percentages greater on the left side & towards the rear. When you start with more weight to the left & rear, your hoping to balance the weight equally when you enter the corner once weight is transferred. If you could run your car, with the weight being equal at all 4 corners entering a turn, then you would run faster than anyone else in the corners. With perfect weight distribution you would have perfect tire temperatures. Perfect tire temperatures equals the maximum traction you could attain. This is what were all trying to accomplish with every single adjustment we make on a racecar.

Finding the overall correct weight distribution isn't easy & varies with every track. As heavy as WC cars are, left side bias on an oval is simple to deal with. Always keep as much weight as possible towards the left side of the chassis. Within NASCAR Racing we are allowed left bias adjustments from 54.2% left side weight, to 45.8%. Whenever your dealing ONLY with left hand turns, always keep the left side weight at 54.2%. More left side weight allows you to take left hand turns at a higher speed.

The only reason you would want to adjust the left side bias is when you're dealing with both left & right hand turns. These obviously would be the road courses. You'd probably want to run an even left bias of 50% at these tracks. Although at a track where there are more right hand turns than left, you may favor a higher right side percentage. This will allow you to get through those right handers a little more quickly, but at the sacrifice of losing speed going through the left handers. This still could be advantageous if there are few more turns going right than left.

Left Bias synopsis:

Higher left side bias will help turn the car left into a corner & loosen a chassis when making left hand turns.

Higher right side bias will cause the car to Understeer when making a left hand turn.


Rear Sway Bar
The purpose of the rear sway bar is the same as the front sway bar except it controls body roll at the rear of the car. The rear sway bar connects in the back between both rear lower trailing arms. As with the front sway bar, the rear is adjusted by changing the diameter of the bar. The rear sway bar range of adjustments are as low as 0.000" to a max of 1.000". This differs by a half inch over the front sway bar, yet the rear offers no less than 26 adjustments in 25 hundredth increments. The larger the bar the stiffer the rear becomes. But by making the rear stiffer, it has just the opposite effect that occurs at the front. A larger rear sway bar will actually loosen the car up due to the fact that the way the weight is being transferred at the rear, is just the opposite of the the way the weight gets transferred at the front of the vehicle.

Rear Sway Bar synopsis:

The larger the bar the looser the chassis.

The smaller the bar the tighter the chassis.


Ride Height
The chassis ride height is simply the distance measured in inches from the bottom of the frame rails to the ground. This measurement is taken at all 4 corners of the car where the frame rails are lowest to the ground. Usually just behind the front wheels & just in front of the rear wheels. Ride height is adjusted by turning down or up on load bolts located at each corner of the car on top of each spring. NASCAR has limits as to the minimum ground clearance allowed. Ideally you would want to run your chassis as low as possible. The lower your ride height, the lower your center of gravity. The lower the center of gravity, the lower the overall weight is to the ground. The lower the weight the less weight transfer will occur while cornering.

There are a number of criteria that must be considered when adjusting ride height. Those include chassis clearance, spring rates, camber change, front & rear roll centers, & rear steer. The front roll center & rear steer isn't an option for us to adjust within NASCAR Racing. These adjustments are built into the chassis itself. Rear roll center can be taken care of by adjusting the track bar. Camber can be adjusted at any time & will have to be readjusted after making a ride height change. This is because your camber angles & contact patch of the front tires will change as your car is raised or lowered. Check you tire temperature for proper camber angles. The most important factor we must consider is chassis clearance.

If the ride height is set to low the car may bottom out on the track. This will more likely occur at high speed high banked tracks where the centrifugal forces are higher higher or at road courses where there are dips in the track. If the car bottoms out in the rear you will most likely get loose. Bottoming out up front will result in a push. If you bottom out you can do one of two things. You can raise the ride height or run stiffer springs. Personally I've always believed that lower was better, but I also believe that softer springs are better. On paper, the softer the springs & lower the car, the better off you should be. Again, this theory depends on a lot of other adjustments set within the chassis, so experimentation is the only real answer.

NASCAR Racing allows us to adjust the ride height on the LF, LR, & RR. The RF is non adjustable & grayed out, although changing the ride height at any of the other three corners will result in changing the height of the RF. Raising the ride height at the LF & RR corner will also automatically raise the RF. Lowering the ride height at those same corners will also lower the RF. The corner that is opposite is the LR. Raising the LR will actually lower the RF ride height, taking weight off the RF & thus loosening the chassis. At the LF we are allowed to set the ride height as low as 4.50" & as high as 6.00". The LF is always the lowest point of the car & probably should always be set at 4.50". Since raising the LF will raise the RF, your raising the entire front of the car when you raise the LF. The higher the front of the car the tighter the car will be.

The LR can also be set as low as 4.50", but can be adjusted a half an inch higher than the LF to 6.50". The RR is usually the highest point of the chassis & can only be set as low as 6.00" & as high as 7.50". Adjusting the ride height effects the way weight is being transferred when cornering. Running a higher LR ride height also puts more weight on the RR. This will cause a loose condition entering the corner. Just the opposite is true when running the higher RR ride height & will create a tight condition upon entry into a corner. By adjusting the split between the LR & RR you will get different degrees of over or understeer.

Another thing you must consider when raising the ride height in the rear is how it affects the aerodynamics of the car. Raising both LR & RR ride heights raises the entire back of the car higher into the air. With that big spoiler running across the back, it will create more drag because it will be catching more wind. This will slow your straightaway speed. With more wind catching the spoiler it will also create more downforce on the back of the car which should allow the back of the car to stick better in the corners. Running a higher ride height may allow a lower spoiler setting. Trial & error will prove worthy here.

Experimentation & accepting the less of all evils should be your goal when adjusting ride height. Springs will play an important rule in determining your overall ride height. In general, the lower the car, the faster the car should be, but possibly at the expense of bottoming out. Give & take will be required in this area.

On larger tracks where moderate acceleration occurs at the mid portion of the corner, having the CG too far forward will result in a larger wheel steering angle in the corner and typically a push (understeer) exiting the corner.

On short tracks where you have heavy acceleration, having a CG too far forward can result in rear wheel spin and a car that feels loose (oversteer) when trying to exit the corners.

B. The higher the CG is above the ground the more weight will transfer to the outside tires in a corner. A higher CG can also exaggerate the affects of Tip D below. Raising or lowering the CG can impact suspension geometry such as rear axle steer or camber gain in the front suspension.

C. Let the front roll center fall where it may in order for the front suspension to have good camber curves. Use the rear roll center to tune your race car's handling. Elevating the rear roll center tends to make the car looser (oversteer) in the mid portion of the corner when the centrifugal force is highest.

D. Many people refer to this parameter as roll couple distribution. No matter what you call it, increasing the Front % and decreasing the Rear % will tend to create a larger steering wheel angle and typically result in a mid turn push. There are no fixed numbers for this parameter. Your settings back at tip A will affect your ideal numbers.

E. Anybody can crank on the weight jacks until the race car has balanced handling. Cross weight preload is a way of measuring how efficiently the car is balanced. Ideally, the preload should be less than +/- 25 pounds. If the car is balanced and right front is greater than +25, then the car is telling you it wants a stiffer RF spring or a bigger sway bar. If the right rear is greater than +25, then you can likely benefit from a stiffer rear spring. After you make the spring change it will be necessary to readjust your corner weights.

F. Excessive split (left to right) can cause the car to lack high speed directional stability and/or be twitchy on heavy braking. With higher corner banking, increasing the LF & RR wheel rates will make the car turn too easy and often makes the car loose.

G. Typically for pavement tracks the front has a larger number. Dirt tracks typically require a larger number at the rear. In all cases, changes that decrease the rear number make the car tighter and increasing the rear number makes the car looser in the turns.

While weight jacking is a quick and simple way to change the handling of the race car, it is still a crutch. Follow instructions in the manual on how to interpret the preload and determine what the race car wants for springs.

Before your race car goes on the track (or at the shop) the tires are "Cold." Once the car is at speed for a few laps on the track the tires warm up. As soon as you stop the tires are still "Hot." Typically, there is a pressure difference in the tires between the "Hot" and "Cold" conditions. "Roll out" is the circumference of the tire and measured by pulling a tape measure all the way around the tire. This measurement can change from cold to hot conditions just like the pressure.

A computer is just dumb box. It only know what you tell it. For example, if you were to race your car and have the right front brake rotor glowing bright red you would see this and would be registered in your brain. The computer can not see t he car and does not know that a large heat source is near the wheel and tire.

The temperature of a wheel can be elevated to the point where more heat is reaching the air inside the tire from the hot rim than is coming from the tread surface of the tire. If the software were to read only the tire temperatures it may suspect a slightly high air pressure, but with the rim temperature the software would know about the heat coming from the brake rotor.

A good place to take the rim temperature is where the center flange of the wheel meets the rim portion of the wheel.

Ride Height synopsis:

Too low a ride height could cause the car to bottom out.

The higher the RF ride height the tighter the car will be.

The higher the REAR ride heights, the more drag on the straight-aways, but the better the rear will stick in the corners.

A higher LF will tighten the chassis.

A higher LR will loosen the chassis.

A higher RR will tighten the chassis.

A higher LR lowers the RF and may cause the RF of the chassis to drag.


Setup Notes
Within the garage area of NASCAR Racing we are given the option of keeping track of our adjustments during practice sessions. Due to the importance of good note keeping, I'm going to once again remind everyone the importance of keeping track of various adjustments made throughout practice sessions.

It is critical to take notes after every adjustment you make. With all the adjustments available to make, it's real easy to forget what adjustment you made 3 practice sessions ago. Record keeping is important. If you do go the wrong way with an adjustment you can always set it back to where it was before making the change by simply referring back to your notes. By tracking & logging information, it also allows you to refer back to them to see how you progressed to cure your handling problem. These notes could be useful for setups at tracks with familiar configurations which can turn out to be a real time saver. By keeping track of adjustments, you will be able to refer back to your notes to see what worked & what didn't. This will help you decide what to adjust if a similar situation arises at another track.

Above I've included two setup sheets for taking notes. You could also use the setup notes option within the garage area to track your changes. I personally would rather track notes on paper because they are are easier to refer to when trying to set up a car at another track with a similar configuration. What I do like to keep track of in the setup notes area is what type of tire wear I get with the current setup. Before running an event, I refer to these notes so I know what tire will wear 1st, & when approximately I will have to pit. Fuel mileage is another thing to keep track of. Knowing how many laps you can get on a fuel run will allow you to keep in the back of your mind, when you will be forced to pit. Can I make it on a full tank of fuel or will I need tires first. If so what lap will I have to pit should we go green the whole way.

Top speed & or lap times is also a must to keep track of. I also like to keep track of how the car reacts as tires wear, as well as how it performs with less fuel in the car. How bad do lap times decrease over X number of laps. What chassis adjustments could I make during a pit stop to help counter react the way the chassis performs with less fuel. Perhaps a track bar or tire pressure adjustment would be the way to go when pitting after so many laps. All these types of questions I have answered before entering a race because of good note keeping. Keeping track of these types of notes in the setup notes section of the garage area will allow you to perform better on the track & could even get you a win by knowing how your chassis will react before even turning a lap.

After running so many different tracks & working on so many different setups, it's real easy to forget how one setup reacts over another. Simply reading your setup notes will remind you once again what you can expect from the setup you will be running before even getting on the track. If you have multiple setups for various weather conditions reviewing these notes will allow you to choose what setup to run given the current track conditions. This is where using the track notes section of the garage area comes in handy (read the section on track notes).


Shocks
Shocks are designed to control the up & down movement of the suspension caused by weight transfer as well as bumps. A shock controls the speed at which the spring moves. Without shocks a car would handle like a boat in the water, swaying back & forth while moving up & down. Understanding shocks & how they work will give you a major advantage over those that don't. Controlling the chassis with the proper shocks is the key to getting through a corner smoothly & effortlessly. Shocks are used to help control handling problems & can even be used to induce desirable handling characteristics.

Of all the questions I am asked regarding setup options, shocks are by far the most asked & most misunderstood of all the setup options available to us in NASCAR Racing. Shocks are a very easy issue to become confused about. At times, too much or too little of the same adjustment on the same shock can produce the same exact results in the chassis. (i.e. it's possible to have a push with a RF shock that is both too stiff or too soft). Such results end up in total confusion as which way is the right way to go with an adjustment. The most important thing to remember regarding shocks, is that the stiffer the shock, the less grip it will have at the corner or end of the chassis.

Shocks do NOT control the amount of weight transfer in a corner. They will however control how quickly the weight is transferred. Shocks used on WC teams are rated from 1 through 9. 1 being very soft while 9 being very stiff. We also have the same choice for shock adjustments within NASCAR Racing at all four corners of the car at tracks where NASCAR doesn't mandate specific shock settings. Shocks are numbered for both compression & rebound. The compression of a shock is when it is being pressed down. The rebound is when it is being pulled back up. By adjusting the valving (changing the numbers) within the shock, we are able to change the stiffness or weakness of that shock when it is both compressed & pulled back or rebounded.

When you have a shock that has the same number compression as rebound it is said to be a 50/50 shock. This means that the shock when compressed, has the same resistance when pulled apart. A shock with a compression rating of 9, & a rebound rating of 9, is telling you that the shock is really hard to compress & just as hard to pull back apart or rebound. A shock with a compression rating of 9 & a rebound of 1 is what they call a split valved shock. This shock would be stiff to compress, but would rebound or pull apart real easy. Through adjustment of the shock valves you are able to control how quickly weight is unloaded left to right, & front to rear. By adjusting the valving of each shock you can fine tune your chassis through a corner. Once you understand this concept of how shocks work, you will be able to use that knowledge to turn faster & more consistent laps.

When discussing shock tuning in depth, a basic understanding of dynamic weight transfer and its effect on tire loadings is necessary. Dynamic weight transfer is the transferring of weight from side to side during cornering, from rear to front during deceleration and from front to rear during acceleration. The distribution of weight that transfers is affected by the rates of the springs used in the chassis. Basically, if one of a pair of springs receiving weight is stiffer than the other, the stiff spring receives proportionately more weight than the soft spring. The rate at which a tire is loaded or unloaded during dynamic weight transfer is affected by the compression & rebound of the associated shock. In rebound, a stiff shock slows down and a soft shock speeds up the unloading process. In compression, a stiff shock slows down and a soft shock speeds up the loading process. However, excessively soft or stiff shocks can produce effects opposite to those stated. Consequently, by changing the stiffness of the shocks used on a race car, we are adjusting the loadings on the tires at different points on the race track. If done correctly, good handling will result.

Now that you understand the compression & rebound of a shock, you must learn how & when they are used while cornering. The easiest way for me to explain when a shock is doing it's most work, is by using an ordinary automobile as an example. Imagine a vehicle going down the highway at 50mph. Now imagine this vehicle slamming on it's brakes. What occurs in the chassis? When you slam on the brakes all the weight is transferred to the front of the vehicle & the nose of the car dives while the back of the car raises up. What are the shocks going through in this state? The front shocks are being compressed & the rear shocks are extending or rebounding. Generally speaking, this is the exact same thing that occurs in a racecar upon entering the corner. (minus the locking up of the brakes of course) The shocks are going through the same basic process as the regular street car. Therefore if your having troubles getting into the corner, you would adjust the front shocks compression, & or the rear shocks rebound, since that's the stages of the shocks being utilized upon entry into a corner.

Let's take the same street vehicle & imagine it at a stand still in a parking lot. Giving the car full throttle what occurs? Just the opposite of what was explained above. The front of the car lifts while the rear of the car squats. The shocks up front are rebounding & the rear shocks are compressing. The shocks on a race car are going to react the same way in the middle of a corner when your chassis takes set to full throttle. Therefore if your having problems exiting the corners under acceleration, you would look at adjusting the rebound of the front shocks, & or the compression of the rear shocks.

Keep in mind the above comparisons are being used to help you better understand the basic concepts of shocks & how & when they perform. In reality there is a lot

Thanks to raceline central for the great info.

ESR Staff