Camber Offset Calculator v1.1. Enter the Diameter of your tire on your wheel. Then the Camber Angle in Degrees, it can be POSITIVE or NEGATIVE. Press CALCULATE to find other values. Hit RESET to clear the form and SAMPLE if you want to see a sample calculation. A NEGATIVE offset number means the wheel is tipped in as the picture to the left shows.
Static ride height is one of the key setup adjustments, and also one of the easiest to get right. For example, for many cars converting a qualifying setup into a race setup (or vice versa) only means adjusting fuel and the static ride height. In this article we’ll explain what ride height entails, how you can adjust it, and how it affects other setup adjustment.
Static versus dynamic ride heights
Ride height (measured in mm or in) defines how far off the ground the chassis sits. Static ride height is what you configure in the garage. Dynamic ride height is the actual ground clearance at any moment in time as the car goes around the track. The dynamic ride height changes throughout a lap, for instance when a car goes over a curbstone, or when downforce compresses the springs. The dynamic ride heights also changes throughout a stint, for as the fuel burns off and the tank empties, the car becomes lighter and therefore ‘rises’.
Ride height (measured in mm or in) defines how far off the ground the chassis sits. Static ride height is what you configure in the garage. Dynamic ride height is the actual ground clearance at any moment in time as the car goes around the track. The dynamic ride height changes throughout a lap, for instance when a car goes over a curbstone, or when downforce compresses the springs. The dynamic ride heights also changes throughout a stint, for as the fuel burns off and the tank empties, the car becomes lighter and therefore ‘rises’.
Depending on the location of the ride height sensor (e.g. splitter, tire, etc) and its vertical offset, the ride height as measured in the garage (and as reported in telemetry) does not necessarily equate the actual ground clearance. For example, the splitter ride height sensor (on cars that have one) may be positioned a few centimeters above the bottom of the splitter. As a result, you’ll get a non-zero reading even if the splitter bottoms out. And obviously every single car is different, so the first thing you need to find out when you start setting up a new car is what “bottoming out” means in terms of ride height reading.
Purposes of changing the ride height
1: Lower center of gravity means less lateral weight transfer, which means more grip
For cars that are not very aero dependant the ride heights are primarily used to affect the center of gravity. A lower sitting car generally has better handling because a lower center of gravity means less lateral weight transfer. And we’ve discussed in 5.3, lateral weight transfer reduces the total available grip.
1: Lower center of gravity means less lateral weight transfer, which means more grip
For cars that are not very aero dependant the ride heights are primarily used to affect the center of gravity. A lower sitting car generally has better handling because a lower center of gravity means less lateral weight transfer. And we’ve discussed in 5.3, lateral weight transfer reduces the total available grip.
2: Balance between downforce and drag
For cars where aero is a defining factor in car setup, the ride height is the key to optimizing aero performance. Each car is different, but in general there’s an ideal ride height range that produces maximum downforce. Similarly, there is an ideal ride height range that minimizes aero drag. These two ranges may or may not overlap. Each car is different and it takes a bunch of experimentation with each new car to find out what works and what doesn’t. By statically and/or dynamically adjusting the ride heights, you can optimize the aero performance of the car.
For cars where aero is a defining factor in car setup, the ride height is the key to optimizing aero performance. Each car is different, but in general there’s an ideal ride height range that produces maximum downforce. Similarly, there is an ideal ride height range that minimizes aero drag. These two ranges may or may not overlap. Each car is different and it takes a bunch of experimentation with each new car to find out what works and what doesn’t. By statically and/or dynamically adjusting the ride heights, you can optimize the aero performance of the car.
3: Ground clearance
The final factor, relevant for both downforce and no-downforce cars, is clearance from the ground. You may want to adjust the ride heights to avoid bottoming out on bumps and curbs. Like discussed in the spring rates article, bottoming out can cause handling issues as one or multiple tires may become unloaded or lose contact with the track altogether, and it can also severely lower speed when the car is dragging onto the track.
The final factor, relevant for both downforce and no-downforce cars, is clearance from the ground. You may want to adjust the ride heights to avoid bottoming out on bumps and curbs. Like discussed in the spring rates article, bottoming out can cause handling issues as one or multiple tires may become unloaded or lose contact with the track altogether, and it can also severely lower speed when the car is dragging onto the track.
Example
One of the most common setup scenarios is converting a qualifying setup to a race set. In most cases the additional weight due to the added fuel is bringing the car ‘out of tech’, which means it’s too close to the ground and isn’t legal to race. To pass tech inspection, you need to raise the ride height.
One of the most common setup scenarios is converting a qualifying setup to a race set. In most cases the additional weight due to the added fuel is bringing the car ‘out of tech’, which means it’s too close to the ground and isn’t legal to race. To pass tech inspection, you need to raise the ride height.
Typically, it’s best to keep a note of the target ride heights as they are in the qualifying setup and try to resemble those as close as possible on the race setup. In order to increase ground clearance, you’ll need to decrease the perch offset on each wheel, or increase the pushrod length (when available). Matching front and rear ride heights may be all you need to convert a qualifying setup to a race setup.
For cars where the gas tank is located far from the center of gravity of the car (e.g. the BMW Z4 GT3 has it’s tank fairly far back in the car), setting the race fuel ride heights could be trickier. As fuel is burnt throughout a stint the front or back of the car will get lighter, increasing the ride height. You may have to take this into consideration when determining the static ride heights with a full tank.
How suspension geometry affects ride height
Different simulators implement this differently, but in iRacing you cannot set the ride heights with one parameter. Instead, on each wheel you can adjust the spring perch offset, or increase the pushrod length (when available). Adjust these properties until your achieve the desired measurement for ride height.
Different simulators implement this differently, but in iRacing you cannot set the ride heights with one parameter. Instead, on each wheel you can adjust the spring perch offset, or increase the pushrod length (when available). Adjust these properties until your achieve the desired measurement for ride height.
Keep in mind that many suspension elements are connected. Significant changes to spring perch offset, or to pushrod length could also impact camber and toe. Each time you make a change to ride heights you should remember to also take a look at camber and toe. If your camber has changed, change it back to the old (desired) value. This may change your ride height again, so you may have to do a few iterations of ride height adjustment, camber adjustment, until you achieve the desired result. The same applies to each wheel’s toe-in.
When adjusting ride heights
You need to keep ride heights in mind each time you change any of the following:
Spring rates: Stiffer springs raise the car, softer springs bring it closer to the ground. When changing spring rates you want to make sure that you maintain the ride height from before the spring rate adjustment (otherwise you’ll be applying two changes to the car).
Tire pressure: The tire is effectively a spring, and significant changes in tire pressure affect ride heights too.
Camber & toe: As already discussed, camber and toe adjustments may affect the ride height. Modify the suspension geometry so that you achieve the new desired camber (or toe) at that same ride height.
Fuel load: Added fuel (per the example above, for full race distance as opposed to for qualifying) adds more weight to the car, which compresses the springs more, which reduces the ride heights. Each time you add and remove fuel you’d generally want to do so without actually modifying the static ride height (with some exceptions, depending on car or track).
You need to keep ride heights in mind each time you change any of the following:
Spring rates: Stiffer springs raise the car, softer springs bring it closer to the ground. When changing spring rates you want to make sure that you maintain the ride height from before the spring rate adjustment (otherwise you’ll be applying two changes to the car).
Tire pressure: The tire is effectively a spring, and significant changes in tire pressure affect ride heights too.
Camber & toe: As already discussed, camber and toe adjustments may affect the ride height. Modify the suspension geometry so that you achieve the new desired camber (or toe) at that same ride height.
Fuel load: Added fuel (per the example above, for full race distance as opposed to for qualifying) adds more weight to the car, which compresses the springs more, which reduces the ride heights. Each time you add and remove fuel you’d generally want to do so without actually modifying the static ride height (with some exceptions, depending on car or track).
Up to you
Once you understand what ride heights are and what interactions ride heights have with suspension geometry, you need to spend a lot of time testing and experimenting with different settings in order to find out what works with each specific car. And in a later article we’ll look more closely how to approach dynamic ride heights.
Setup The Race Car
Camber:
Camber is the inward or outwardtilting of the front wheels. Negative camber is the tilt of the top of thewheel towards the center of the vehicle. Positive camber is the tilt of the topof the wheel away from the center of the vehicle.
Camber adjustments are made tomaintain the maximum amount of tire tread on the ground during suspensionmovement and body roll through the corners. Proper camber adjustments arecritical to achieving maximum cornering speeds. When camber is set correctly itallows the entire surface of the tire to adhere to the track maximizing thetire contact patch when taking a corner at high speed.
Proper camber adjustments areachieved by reading tire temperatures. The goal here is to get eventemperatures across the whole tire.
On all tracks except road coursesyou need to run with negative camber on the right front and positive camber onthe left front. This aids in getting the car to turn left. How much camber youmight ask? It varies depending on track banking, spring stiffness, body rolland other considerations.
Generally add just enough camberso the inside of the RF tire runs a degree or so hotter then the outside. Thenbackup a notch to get the tire temperatures even again.
The decision on the LF camber isa little more difficult. Adding positive camber to the LF doesn’t help quite asmuch on ovals as adding negative camber to the RF. More importantly, if you hitthe apron with a lot of positive camber on the LF there will be a tendency tolose control of the car as the LF gets more of grip and the RF looses grip.
This will cause the car to turnin hard toward the apron and only makes the situation worse. Be a little moreconservative when working with the LF camber. Work mainly on keeping the carunder control when you get a piece of the apron.
When competing on a road courselike Watkins Glen or SearsPoint, or any track where your making both left andright handed turns, you will typically want negative camber on both the LF andRF tires. The reason for this is the outside tire on a corner supplies most ofthe cornering force and will therefore dominate that corner. By adding negativecamber to both tires you help the car turn better in both directions.
Rear camber is not as critical asfront camber due to the fact that the rear-end is a solid axle. The same theoryholds true though as you might want negative camber on the RR and positivecamber on the LR on an oval track. On a flatter track you may not need anycamber in the rear. Stagger built into the Goodyear tires will naturally createsome negative camber in the RR and positive in the LR as is.
Knowing how to read andunderstand tire temperatures will be the determining factor in how much camberto set in your wheels. In fact it’s the only way to properly adjust for correctamount of camber. Since you must constantly monitor tire temperatures you willalways be readjusting camber (at least in the front).
Just when you think you have yourtire temperatures and camber perfect, you’ll change a spring or tire psi tofind more speed, or the weather will be different forcing you to make someadjustments elsewhere. All that hard work you spent on achieving those perfecttemperatures will have to be thrown out the window and the whole process beginsonce again.
One final thought, if the tiretemperatures on the inside and outside are not even, then your are going toincrease wear and a shorter life of that particular tire. Too much camber willdecrease the size of the tire contact patch and reduce the amount of corneringforce available.
How camber effects the handlingof the chassis:
More negative RF camber allowsthe car to turn into a corner quicker, which will loosen up the chassis.
Less negative RF camber takesaway some of the pull to the left. The car won’t turn as quick into a corner,which will tighten the chassis.
More negative LF camber willreduce the pull to the left while tightening the chassis from the middle out.
More positive LF camber willincrease the pull to the left and allow the car to turn into a corner quickerloosening the chassis.
More positive camber in the RRwill loosen the car from the middle out.
More negative camber in the LRwill loosen the chassis entering a corner.
Caster:
Caster is a major factor whichprovides a vehicle with directional stability. Directional stability is theability of the vehicle to travel straight ahead with a minimum of steeringcorrections by the driver.
Viewing the car from the side,Positive caster is the backward (toward the rear of the vehicle) tilt of thesteering axis and Negative caster is the forward tilt of the steering axis.Caster is measured in degrees of angle, the amount the steering axis is tiltedfrom a true vertical axis. Do not confuse this with camber which is the inwardor outward tilt of the wheel.
To understand the principle andeffect of caster on the steering system, let’s examine the ordinary householdfurniture caster.
When a piece of furniture oncasters is pushed, the casters turn on their pivots until the wheels are inline with the direction of force applied and the wheels are trailing in back ofthe pivot. In this position, the furniture will roll easily and in a straightline. Therefore, it can be seen that when a force is applied to the pivot ittends to drag the wheel behind it.
The reason lies in the fact thatthe projected centerline of the caster pivot strikes the ground in front of thecontact patch of the wheel.
This simple principle applies toa vehicle. If the steering axis pivot is tilted backward (toward the rear of thevehicle), the projected centerline of the pivot strikes the ground ahead of thecontact patch (which is positive caster). When the vehicle is driven forward,the pivot is behind the wheel, giving the car directional stability.
When setting your chassis you’llwant to tip the top of the wheels back adding positive caster to provide youwith that straight ahead directional stability. Under NO circumstances do weuse negative caster, even though the adjustment range is from -2.0 to +6.0.
How much caster do I need?
The amount of caster set into thechassis depends on two factors:
The amount of weight on the frontwheels and the feel of the steering effort to the driver.
The amount of positive casterdepends a great deal on the speed of the race track and the amount of weight onthe vehicle front end. The lighter the weight on the front end, the greater theamount of positive caster.
For example, a Porsche roadracing car with only 40% front weight may have 61/2 degree positive casterwhere as a NASCAR stock car with 51% front weight may have only 31/2 to 4degrees positive caster with both cars running on the same track. Race carsthat weigh 3500 pounds and more, front caster angles run between 3 and 5degrees positive.
The more positive caster a carhas, the greater the straight line stability it will have. The car will havegreater high speed stability and require less constant attention on the part ofthe driver. The faster the track gets in terms of speed, the greater thepositive caster setting.
Cars running at Daytona and Talladega have as much as41/2 to 51/4 degrees of positive caster on the RF wheel. On shorter trackswhere speeds are more moderate, the RF caster is from 3 to 33/4 degreespositive
Another factor to consider is thesteering device you maybe using. (i.e. force feedback) The more positive casterthe more feedback you will feel as a driver. More caster can also provide amore difficult steering effort, especially with a force feedback wheel.
So why not crank the casterpositive as far as it will go? Because too much positive caster also has it’sdrawbacks. When you turn a car left with positive caster the LF rises while theRF drops. This changes the weight on all 4 corners of the car. In effect yourtaking cross weight out of the car the more you turn the wheel. The morepositive the caster, the more cross weight there is being removed. The morecross weight you remove the looser the car will get.
Caster stagger:
Another element that must beconsidered is the caster split, or caster stagger as it is called. Casterstagger is simply using different settings on the LF wheel than the RF. At anytrack where the car is making only left turns, the caster is staggered withmore positive caster on the RF than on the LF. The reason for using caster staggeris to help the wheels steer themselves to the left in the corners.
For short track racing, manydrivers prefer to use as much caster stagger as possible (up to a maximum ofabout 4 degrees). The greater the amount of stagger will allow the driver toalmost allow relax the steering wheel completely entering a turn, letting thecar steer itself into the corner.
The drawback of using so muchcaster stagger though is the increased effort in crossing the steering wheelover to the right to correct for oversteer. The greater the stagger, thegreater the effort required to turn the wheel back past the straight aheadcenterline of the steering wheel.
At higher speed race tracks, themore the caster stagger closes up. Daytona and Talladega for example drivers generally useno more than 11/2 degrees of caster stagger. The amount of caster stagger istotally up to the driver’s preference and several settings should be triedbefore the final setting is arrived at.
How caster effects the handlingof the chassis:
More positive caster will loosenthe chassis the more the wheel is turned through a corner.
The car will pull to the sidewith the lower amount of positive caster.
The higher the caster stagger,the easier the car will turn into a corner. The less steering effort required.This will tend to give you a loose feeling upon corner entry.
Front toe-out:
Toe-in or toe-out is thedifference in distance between the extreme front and extreme rear of the tireswhen measured at spindle height. Front toe-out is utilized to help minimizetire scrub and rolling resistance, while cornering. It’s used in oval racing inorder to produce more optimum slip angles for cornering.
We can make adjustments thatrange from -0.200″ of toe-in through 0.200″ inches of toe-out. Never use atoe-in condition. The majority of setups usually require a setting of less than0.125″ inches of toe-out. Don’t run anything less than 0.025″ and no more than0.175″ inches max. toe-out on any track.
Excessive amount of toe-out willcause tire scrub both on the straightaway and cornering. Warning, running toomuch toe out will scrub off speed down the straightaway. At large tracks likeDaytona and Talladegayou would minimize toe-out and at small tracks maximize it. Anotherconsideration, adding more toe-out will add Understeer to the chassis at entryand at mid-corner.
To monitor toe-out, read the tiretemperatures. Toe-out is read on the inside edge of the RF and the outside edgeof the LF. If you have too much toe-out these areas of the tires will heat upmore. You should set camber first then check this condition for toe-out.
Start with an adjustment of 0.050and you will be close. Adjust the toe-out only when the rest of the chassis isclose to being correct.
Tire pressures:
Tire pressure is anotheradjustment that will aid in achieving the best possible grip. As a generalrule, lower tire pressure generates more grip, but at the expense of highertemperatures and more rolling resistance.
Tire temperatures play a criticalrole in the effectiveness of a tire and you should try to keep them in therange of 190 to 220 degrees. If a tire is too cold, it will become stiff,reducing the stiction forces. If it becomes too hot, it will begin sheddingrubber, decreasing grip and adding to the wear, while reducing its life.
Rolling resistance is a forcethat opposes the rotation of the tire, effectively slowing the car down.Increasing tire pressure will reduce the rolling resistance while, increasingthe top speed of the car. However, it will typically reduce the grip for thattire as well.
A third factor that comes intoplay with regard to tire inflation is the spring effect of the tire. 1 lb ofair pressure adds an additional 15 lbs of spring to the sidewall of the tire,effectively stiffening the suspension on that corner of the car.
A fourth factor to be aware of,when dealing with tire pressures, is that you are also changing the weight ofthe car on that corner. By raising or lowering tire pressure your changing theride height of the chassis. Changing the ride height adds or subtracts weightfrom that corner of the chassis.
This is another way that tirepressure can actually react like a spring. Adding more tire pressure makes thatsame spring a little stiffer. Lowering tire pressure will make that spring abit softer. In other words if you lower the RF tire pressure your also makingthe RF spring weaker.
Making the RF spring weaker willloosen the chassis. When you understand how springs work, you’ll be that muchfurther ahead to understanding how tire pressures work. This will become veryimportant to be able to adjust the chassis during a race.
Tire pressure is simply how muchair you have in the tire. The hotter tires get, the more they expand. Aircontains moisture. Moisture becomes steam as the air gets hot and increasespressure.
Some teams actually don’t use airin their tires, they use nitrogen. Nitrogen is preferred over air because itdoesn’t expand as much with temperature changes because it doesn’t containmoisture. Since it’s impossible to remove all the moisture from a tire, it willstill change pressure as temperatures rises.
This can be noted after running atest session and checking your tires both hot and cold. When tires expand itchanges the size of the tire which in turn changes the weight on that wheel.This can be either a negative or positive situation depending on your chassisneeds.
Tire pressures can be adjusted onall 4 tires from as low as 5 psi, to as high as 15 psi. Improper tire pressurecan cause an ill handling car. Correct tire pressure can be determined byreading tire temperatures.
A tire with a temperature readinghigher in the center of a tire indicates an over-inflation.
A tire with a lower centertemperature, when compared to the inside and outside of a tire indicates aunder-inflation. Over inflated tires will have a tendency to make the cartight.
Tires are the only adjustment wecan make during the race that allow you to compensate for differences betweenentrance and exit problems. They work in much the same way as shocks.Increasing pressure is like stiffening a shock and will decrease grip on thatcorner. Lowering pressure is like softening a shock, increasing grip on thatcorner.
To fix a loose condition into acorner:
Increase RF tire pressure and/ordecrease RR tire pressure
Push all the way through the exitof a corner:
Increase LR tire pressure and/ordecrease LF tire pressure
Tire stagger:
Altering tire pressures allows usto slightly modify the stagger. Stagger is the circumference of the right sidetires compared to the left side tires. The best way to describe stagger is byusing a white Styrofoam coffee cup. You know, the kind that is bigger around onthe top than on the bottom.
Take that cup and lay it over onit’s side on a table. Now push it along the table letting it roll. You see howit turns in one direction. This is stagger. Imagine the larger side of the cupas the right side tires and the smaller side of the cup as the left side tires.See how it turns left? Stagger on a race car works the exact same way.
By increasing tire pressure onthe right side, or decreasing pressure on the left we add stagger to thechassis allowing the car to turn left better through a corner especially underacceleration. I wish we knew exactly how much this works in the game. It’s justsomething to be aware of.
Tire temperatures:
Every adjustment made on a racecar, the goal is to maximize the grip of each tire. Taking tire temperaturesafter the car has had 8 to 10 hard, competitive laps will tell more positivefacts about how the chassis is handling than anything else. Reading tiretemperatures is one of the methods in chassis tuning where it is possible toget away from guessing methods and work with predictable variables.
Comparing tire temperaturesacross the surface of the LF and RF tires it can be determined if each wheelhas the proper camber angles, proper toe, proper weight distribution, as wellas proper tire inflation. By reading the average temperature of the RF andcomparing it to the average temperature of the RR we can tell if the chassis isloose or tight. Comparing diagonal averages indicate the proper amount of wedgein the chassis.
The optimal tire temperatures shouldbe in a range of 100 to 140 degrees. Keep in mind that the hotter the tire thequicker it will wear out. It’s also important to know what the outside andinside temperature of each tire is.
On a short track it is normal forthe inside edge of the RF tire and the outside edge of the LF to be 5 to 10degrees hotter. On a larger track with longer straights, this spread will beeven less. On an oval, the RF tire will have more negative camber, thusresulting in the inside edge of the tire contacting the track more than theoutside edge giving you the higher temperature.
On the LF you will run with morepositive camber, so just the opposite holds true. While cornering thesetemperatures should even out if you have the correct amounts of camber and orweight transfer. The more camber you run, the higher these spreads will be. Ona small track were you spend a lot of time cornering, you’ll find the spreadhigher. This is because your spending more time cornering than on thestraights. If you try to achieve even temps across the tire you may develop apush. This is telling you that you have too much positive camber. Just be sureto check the tire temperatures in the corners.
Comparing the average temperatureof all four tires will tell you which corner of the chassis is working thehardest. To figure the average temperature of a tire, add the 3 temps acrossthe tire and divide by three. If your RF is a lot hotter than the other threetires your probably pushing because the RF is doing too much work. Work on coolingthat tire, by lowering the RF spring and allow the other tires to share some ofthe load.
When a tire is under worked, it’stemperature is a lot lower than the other three tires. Concentrate on thatcorner of the car, by adding weight to that corner, you increase thetemperature of that tire. If a tire is a lot hotter than the other 3 work oncooling that tire.
Loose or tight chassis? Comparethe RF average to the RR average. The RR should be about 10 degrees cooler thanthe RF. As the average temperatures approach the same number the car becomesloose. When the RF is greater than 10 degrees warmer than the RR the car willpush.
Wedge? Check the average of theRF & LR tires and compare them to the average of the two front tires, thento the average of the two right side tires. The diagonal average should be 5 to10 degrees cooler than both the front and right side averages. Warmer you havetoo much cross weight. Cooler you need more wedge.
Toe-out setting? Compare theinside edge of the RF and the outside edge of the LF. If you have too muchtoe-out, the tires will heat up more in these two areas.
The best way to decipher tiretemperatures is to run 10 laps on a particular setup and monitor tiretemperatures. Don’t expect to learn everything reading the temperatures onlyonce. It will take a number of 10 laps sessions to sort out everything that isgoing on with the tires. When analyzing tire temperatures it should be done ina specific order. This is because a problem in one area may mask a problem inanother area. Here is what to do:
Run 10 laps, adjust frontcambers. Run another 10 laps.
Adjust tire psi. Run 10 morelaps.
![Iracing Correct Camber Iracing Correct Camber](/uploads/1/2/5/2/125279898/258181705.jpg)
Adjust toe if needed. Again run10 laps.
Adjust wedge. Run 10 laps.
Adjust for tight or loosecondition based on RF and RR average. Run 10 laps.
Look for overheated or overworkedtire. Adjust on that corner. Run 10 laps.
Repeat the process all overagain. Run 10 more laps.
Oh no, I hear you say. This isgoing to take ages to get sorted out. Yes, it will. But if you want to do itproperly, then this is the only way to get it sorted out.
When checking tire temperaturesit is important to make sure your not locking up the brakes or making anysudden changes in your steering outputs. These will all create erroneous tiretemperatures readings. Let’s try to simplify how to read tire temperatures bygiving you this guideline.
Too much NEGATIVE camber, showshigher temperature on the INSIDE edge.
Too much POSITIVE camber, showshigher temperature on the OUTSIDE edge.
OVER inflated has higher MIDDLE temperaturethan the inside and outside edges.
UNDER inflated will have a LOWERMIDDLE temperature than the inside and outside edges.
Too much TOE-OUT, shows highertemperatures on the INSIDE RF and OUTSIDE LF edges.
Too much TOE-IN, shows highertemperatures on the OUTSIDE RF and INSIDE LF edges.
TIGHT condition when RF is morethan 10 degrees HOTTER than RR.
LOOSE condition when RF is morethan 10 degrees COOLER than RR.
HIGHEST average temperature isthe corner that is being worked the MOST.
LOWEST average temperature is thecorner that is being worked the LEAST.
LESS WEDGE when RF and LRdiagonal average is the SAME or HIGHER than the front and right side average.
MORE WEDGE when RF and LRdiagonal average is more than 10 degrees LOWER than the front and right sideaverage.
Lets look at some examples:
(The I M O reading is the Inner,Middle and Outer section of the tire)
RF
I M O
108 102 94 – Indicates too much negative camber.
I M O
108 102 94 – Indicates too much negative camber.
RF
I M O
94 102 108 – Indicates too much positive camber.
I M O
94 102 108 – Indicates too much positive camber.
RF
I M O
104 88 97 – Indicates an under inflated tire.
I M O
104 88 97 – Indicates an under inflated tire.
RF
I M O
104 110 97 – Indicates an over inflated tire.
I M O
104 110 97 – Indicates an over inflated tire.
RF
I M O
104 98 94 – Indicates correct camber. Overall average temp is 198.6.
I M O
104 98 94 – Indicates correct camber. Overall average temp is 198.6.
RR
I M O
127 125 123 – Overall average temp. is 125. If the RR and RF temp above came offthe same car we would have a very loose race car. The RR is approximately 26degrees hotter than the RF. If this RR is also the hottest tire on the car, itindicates the RR is doing the majority of the work in the corners. This is thecorner of the chassis that needs work on. We need to take some weight off thiscorner to cool this tire. Start by going with a weaker RR spring. This shouldcool this tire and tighten up the chassis.
I M O
127 125 123 – Overall average temp. is 125. If the RR and RF temp above came offthe same car we would have a very loose race car. The RR is approximately 26degrees hotter than the RF. If this RR is also the hottest tire on the car, itindicates the RR is doing the majority of the work in the corners. This is thecorner of the chassis that needs work on. We need to take some weight off thiscorner to cool this tire. Start by going with a weaker RR spring. This shouldcool this tire and tighten up the chassis.
RF
I M O
115 92 86 – Outside edge is too cool indicating it needs more positive camber.Average temp. is 97.6. Let’s compare this with the RR below taken on the samecar.
I M O
115 92 86 – Outside edge is too cool indicating it needs more positive camber.Average temp. is 97.6. Let’s compare this with the RR below taken on the samecar.
RR
I M O
90 88 86 – Average temp. is 88. Thistire is 10 degrees cooler than the RF indicating a neutral handling chassis.This should be good, but we could be faster with a camber change on the RF.Let’s adjust the camber on the RF, run another 10 laps and take temperaturesagain below.
I M O
90 88 86 – Average temp. is 88. Thistire is 10 degrees cooler than the RF indicating a neutral handling chassis.This should be good, but we could be faster with a camber change on the RF.Let’s adjust the camber on the RF, run another 10 laps and take temperaturesagain below.
RF
I M O
100 95 90 – Camber looks much better now. The average temp is 95.
I M O
100 95 90 – Camber looks much better now. The average temp is 95.
RR
I M O
92 90 88 – Average temp. is 90, but now when we compare the average of the RFand RR we find our tire temperatures too close to each other. After the camberadjustment we no longer have a neutral handling car, but one that is now on theverge of becoming loose. Your general feeling may be that the camber changemade the handling worse and it very well may of. But were still heading in theproper direction. You may have to take a step backwards at 1st to take 2 stepsforward later. We can now work on increasing the temp of the RF or work oncooling the RR to increase our average split between the RF and RR. To increasethe heat in the RF try a stiffer spring. To decrease the heat in the RR try aweaker spring. Either way you will make the car tighter. How much of a changedepends on how much it changes your tire temps. Run another 10 laps and reviewyour temperatures again. Eventually you should be faster than your neutralhandling setup with improper camber in the RF.
I M O
92 90 88 – Average temp. is 90, but now when we compare the average of the RFand RR we find our tire temperatures too close to each other. After the camberadjustment we no longer have a neutral handling car, but one that is now on theverge of becoming loose. Your general feeling may be that the camber changemade the handling worse and it very well may of. But were still heading in theproper direction. You may have to take a step backwards at 1st to take 2 stepsforward later. We can now work on increasing the temp of the RF or work oncooling the RR to increase our average split between the RF and RR. To increasethe heat in the RF try a stiffer spring. To decrease the heat in the RR try aweaker spring. Either way you will make the car tighter. How much of a changedepends on how much it changes your tire temps. Run another 10 laps and reviewyour temperatures again. Eventually you should be faster than your neutralhandling setup with improper camber in the RF.
As you can see from the aboveexample there isn’t always an immediate cure. Chassis setup is sometimes likesolving a very complicated puzzle. Experiment and learn as you test. Alwayskeep in mind that you may be going the correct way, but there could be anadjustment elsewhere that may be masking your initial change. Because of this chassissetup can become very frustrating for the novice and experienced alike.
For every change you believe yourmaking for the better, it will have an adverse effect elsewhere in the chassis.If for example your car feels great going into and through the middle of acorner, but is loose on exit, you have to tighten it up somehow. Curing theloose condition exiting the corner now has probably messed up your chassisgoing into the turn. Now you must loosen it up again. It’s a constant battle ofgive and take. By monitoring tire temperatures you can eliminate some of themystery of how and why a chassis is reacting like it does.