Are you using too much camber (>1.5)? real RUF has bigger rear camber too

[sucahyo]

Are you using too much camber? or you just don't care?
Do you ever use car body roll angle as camber angle? Or it is better for you to rely on feeling?

This show real life porsche camber photo

I have some free time to measure some of people car.
The number is car body roll angle, measured from tire elevation relativeness from body. It is front body roll angle if the car picture taken from front, rear body roll angle if it is rear picture.

This is how I measure the number:

Using measurement tool I create a line that is paralel to the car body. Then I move the line to the bottom of the outside tire. Starting from the inside part I create new line to the inside part of the inside tire (sorry, the description is a bit different from the picture, but the result is the same, you can use any way you want). The angle will be show in status bar. You can use photoshop or gimp to measure angle.

My method of camber tuning:
Do this after your other suspension is tuned enough.

Visual method:
- get the picture of the car during cornering, front and rear view if possible.
- measure the angle of front and rear body roll, use this as camber reference for that corner, camber value = body roll
- repeat again on every important corner
- decide what camber that you will use

Feel method:
- Use zero camber, drive the car.
- Tune front camber first, use a step higher camber, like 1.0/0.0, and drive the car, compare.
- Use double of previous value, like 2.0/0.0, and drive the car, compare.
- repeat until you feel loss of traction.
- Use zero camber again, drive the car and compare.
- lower or raise the value until you find camber that have the same feeling as zero camber (drive the zero camber again)
- use the half of the final value as your final front camber.
- do the same thing for rear camber. But you can add more or less to neutralize handling
- adjust the other suspension to match current handling
- repeat the procedure from step 1
- try both direction when you feel the car unneutral, ex. if the car understeer try both increasing and decreasing front camber and also increasing and decreasing rear camber.
- if you are not sure try double value
- always compare to zero camber and reverse value to see if you are doing it right.
- its common to do many lap just to tune the camber.


The roll data:
132cy - not detected


150qm - not detected


300sl134cc - 3.5º


300sl5second5pw - 2.6º


67sw1 - 2.0º


74mb0000 - 0.8º

cliov6inparis1kf - 1.4º


e5511fd - 1.7º


gs30032yn - 1.5º


img00039wk - 0.6º


img00041gh - 1.3º


img00108tp - 2.2º


img00128az - 1.4º


jag101lb - 1.0º


jag12vr - 1.0º


jag155zu - 1.5º


mustang7 - 0.6º

nardo611so - 1.5º

neon92rn - 1.2º


r39023sj - 1.0º


rambig26 - 0.8º

rs6164fq - 1.1º


rs685df - 1.1º


slrmclaren0062sc - 1.2º

slrmclaren0029cl - 2.3º

In all the picture above, the angle seem to range on 0.0º to 2.0º, and if we want to make the tire create flat contact to the road on corner the camber angle should be around that value too. It seem lighter and lower car should have lower camber.

All image is from Bestuners thread (because this is only where picture accompanied with camber setting too). I use picture which I assume being taken when the car is turning.

 

[Speed Drifter]

My thumb of rule is that camber values should be set according to body roll of your car.
lighter and stiffer cars shouldn't need much camber.
but then I don't know how true GT4 is to real life physics or is camber value just something that magically adds more cornering grip when you crank it up..

edit: did I actually type thumb of rule?

 

[Mt. Lynx]

The angle depends on the car and track, but as a rule of thumb I set the camber somwhere between value 0.5 and 3.0. Any higher seem to have a negative effect on the cars overall handling, and any lower seem to have very little effect at all. So for a typical GT racer, like the Vette C5R, the camber ends up somewhere between 1.5 and 1.8 in the rear and 2.3 to 2.8 in the front.
What the values actually portray, I have no idea, but degrees seem likely.

 

[sucahyo]

In GT2 car with 11/11 spring rate have half body roll of 2/2 spring rate. And car with 20/20 spring rate usually have very small (<0.5) or no body roll.
I am curious why everyone seem to use camber more than 2.0 when they use stiff spring rate. In GT2 if your camber is too big (6.0) the tire will have less traction on corner, and in straight line it will reduce tire traction significantly (1 second slower at 1000m test). I don't know if PD change it in GT4, making the tire have more traction in corner and straight when using bigger camber.

It seem to me everyone believe that front camber have to be double of rear camber even though some car have the rear body roll greater than the front (wagon or RR or car with long rear overhang). Maybe everyone use it because they prefer understeer car.

in GT4 it seems 12.0 equal to 12º
I am using this picture (taken by scaff), measured about 12º

 

[Mt. Lynx]

In GT2 car with 11/11 spring rate have half body roll of 2/2 spring rate. And car with 20/20 spring rate usually have very small (<0.5) or no body roll.
I am curious why everyone seem to use camber more than 2.0 when they use stiff spring rate. In GT2 if your camber is too big (6.0) the tire will have less traction on corner, and in straight line it will reduce tire traction significantly (1 second slower at 1000m test). I don't know if PD change it in GT4, making the tire have more traction in corner and straight when using bigger camber.

It seem to me everyone believe that front camber have to be double of rear camber even though some car have the rear body roll greater than the front (wagon or RR or car with long rear overhang). Maybe everyone use it because they prefer understeer car.

in GT4 it seems 12.0 equal to 12º
I am using this picture (taken by scaff), measured about 12º

The reason I´m using a larger camber in the front is just traction! the car in my scenario is rear wheel drive, so the propelling wheels get a smaller camber to increase acceleration grip, and the larger camber in the front makes it possible to brake deeper into a turn. This does not make the car understeer, but rather the opposite. Not much, but that´s how I like my racecars to behave. Camber - like most other settings - are personal preferance, depending on your drivingstyle. I tend to brake in to the turns with many cars, so both camber and toe settings have a significant sayso on the cars behavior during a turn. On front wheel drive cars I use a much smaller camber both front and back.

So the values are most likely degrees I take it? Thats good to know.

 

[sucahyo]

The reason I´m using a larger camber in the front is just traction! the car in my scenario is rear wheel drive, so the propelling wheels get a smaller camber to increase acceleration grip, and the larger camber in the front makes it possible to brake deeper into a turn.

I see.
I think camber should be smaller when we use stiffer spring rate or lower ride height. Do you reduce the camber when you use stiffer spring rate or you use general camber setting?
How do you know you have too much camber?
From what you told I think you usually use spring rate bellow 10, correct?

On some university paper I read that car with heavier front tend to have smaller overall body roll compare to car with heavier rear. So FF car or FR with front bias weight distribution should have low body roll. But I only confirmed it in GT2, I don't know if it work in GT4 too.

 

[Mt. Lynx]

I see.
I think camber should be smaller when we use stiffer spring rate or lower ride height. Do you reduce the camber when you use stiffer spring rate or you use general camber setting?
How do you know you have too much camber?
From what you told I think you usually use spring rate bellow 10, correct?

Explain why camber should be smaller in those cases, please. I usually set springs and rideheight before the camber, and so the camber setting becomes kind of "trail and error", but the camber range I mensioned earlier pretty much applies. Too much camber is most of the time portraid in balance over bumps and curbs. The car becomes "undecisive" over sudden irregularities, and tends to swerve and/or understeer (during turning).
I use a springrate somwhere between 6 and 12, depending on car and track. In some extreme cases I go as high as 14, but that´s usually too hard for me. I tune in a "smooth is fast" fashion, and always try to have the optimum amount of contact with the roadsurface. As always, I end up with a compromise, since cornering and straight line drive are two very different things.

On some university paper I read that car with heavier front tend to have smaller overall body roll compare to car with heavier rear. So FF car or FR with front bias weight distribution should have low body roll. But I only confirmed it in GT2, I don't know if it work in GT4 too.

I´m pretty sure this applies for GT4 as well. And I usually end up with a slightly higher camber in MR cars (0.2-0.4).

 

[sucahyo]

Explain why camber should be smaller in those cases, please.

This is my last test on 1600x1200 GT2 Plymouth GTX. This car have above average body roll. Other car with soft spring and high height usually have bellow 2.0 degree body roll, race car usually have bellow 1.0 body roll.

    spring   height   damper    tire  front anrear ang  RCD
    2.0/2.0  160/160   10/10    N/N     4.4     5.3      45
   2.0/20.0  160/160   10/10    N/N     2.2     1.2      65
   20.0/2.0  160/160   10/10    N/N     1.2     0.8      60
   20.0/20.0 160/160   10/10    N/N     0.6     0.0     100
    2.0/2.0  160/108   10/10    N/N     3.5     3.3      51
    2.0/2.0  108/160   10/10    N/N     2.8     3.0      48
    2.0/2.0  108/108   10/10    N/N     1.2     1.8      40

As you can see, higher spring rate and lower ride height reduce body roll significantly. If the body roll is change I think the camber should change too.

I think this test should be done in GT4 too, because the image resolution in GT4 is definitely higher that make us easy to notice excessive camber. I think you can even zoom the tire on tightest corner to see if you use camber too much, if the tire not meeting the road completely flat then you use incorrect camber.
I think this Jaguar S-Type R '02 have excessive front camber (assuming the photo taken when the car is turning):
Spring Rate - 8.5 | 9.0
Ride Height - 115 | 115
Shock (Bound) - 6 | 6
Shock (Rebound) - 8 | 8
Camber Angle - 2.8 | 1.0
Toe Angle - 0 | -1
Stabilizers - 3 | 4
jag101lb - 1.0º
jag155zu - 1.5º

I use a springrate somwhere between 6 and 12, depending on car and track.

I´m pretty sure this applies for GT4 as well. And I usually end up with a slightly higher camber in MR cars (0.2-0.4).

I see.

 

[Mt. Lynx]

Ok, thanks, and I agree to the fact that camber should change if springs and/or rideheight does. Not necissarily that camber should be smaller in that case, there are more factors to be accounted for too, like stabilisers, dampers, tyre compound and car weight, but as a general rule I can agree that changing springs and/or ridheight have effect on your cambersettings.

 

[sucahyo]

Ok.
As I can't get a close up tire picture or take different camera angle in GT2 I failed to confirm the effect of different stabilizers, dampers, tyre compound and car weight, the angle difference that I measured is too small. So, I think what significantly influence body roll in GT2 is spring rate and ride height.

 

[driftfan01]

Wow. A camber-obsessed tuner. Haven't seen one b4. Oh well The more different, the better

 

[Vision GT]

haha you just haven't seen my MAXED OUT camber FD in GT3

 

[sucahyo]

haha you just haven't seen my MAXED OUT camber FD in GT3

How much ?

 

[Vision GT]

How much ?

MAX so it's far to the right, so the tires look like this /\ you can totally see the front tires looking like this

//---\\

 

[Mt. Lynx]

Yep, it looks mad, I tells ya! Like the axles are broken! And it really sucks to drive with...

 

[Scaff]

The following explination of 'real-world' camber may be of interest.

Camber

The camber angle identifies how far the tire slants away from vertical when viewed directly from the front or back of the vehicle. Camber is expressed in degrees, and is said to be negative when the top of the tire tilts inward toward the center of the vehicle and positive when the top leans away from the center of the vehicle.

Since street suspensions cannot completely compensate for the outer tire tipping towards the outside when the vehicle leansin a corner, there isn't a magical camber setting that will allow the tires to remain vertical when traveling straight down the road (for more even wear), and remain perpendicular to the road during hard cornering (for more generous grip).

Different driving styles can also influence the desired camber angle as well. An enthusiastic driver who corners faster than a reserved driver will receive more cornering grip and longer tire life from a tire aligned with more negative camber. However with the aggressive negative camber, a reserved driver's lower cornering speeds would cause the inside edges of the tires to wear faster than the outside edges.

What's the downside to negative camber? Negative camber leans both tires on the axle towards the center of the vehicle. Each tire develops an equal and offsetting "camber thrust" force (the same principle that causes a motorcycle to turn when it leans) even when the vehicle is driven straight ahead. If the vehicle encounters a bump that only causes one tire to lose some of its grip, the other tire's negative camber will push the vehicle in the direction of the tire that lost grip. The vehicle may feel more "nervous" and become more susceptible to tramlining. Excessive camber will also reduce the available straight-line grip required for rapid acceleration and hard stops.

Appropriate camber settings that take into account the vehicle and driver's aggressiveness will help balance treadwear with cornering performance. For street-driven vehicles, this means that tire wear and handling requirements must be balanced according to the driver's needs. The goal is to use enough negative camber to provide good cornering performance while not requiring the tire to put too much of its load on the inner edge while traveling in a straight line. Less negative camber (until the tire is perpendicular to the road at zero camber) typically will reduce the cornering ability, but results in more even wear.

Even though they have some of the most refined suspensions in the world, the next time you see a head-on photo of a Formula 1 car or CART Champ Car set up for a road course, notice how much negative camber is dialed into the front wheels. While this is certainly an example of wear not being as important as grip, negative camber even helps these sophisticated racing cars corner better.

As can be seen above the entire issue of 'too much' camber is very subjective as it will depend on the car, circuit and to a large degree the driver. So what is too much for driver A may be just right for driver B (subject to sane limits of course).

However as with most areas of tuning its a comprimise, as camber increases so does cornering ability (to a limit), but at the same time straight line stability and braking can reduce and initial turn in can suffer.

The 'correct' camber setting for a car is the one that allows the driver to extract the maximum cornering ability for his/her style without to many sacrifices to straight line performance.

More details of my personal findings regarding Camber settings in GT4 can be found in my tuning guide (link in my sig).

Regards

Scaff


BTW - The picture of my Clio V6 (blue one) used to show camber is in fact a shot taken before I tuned the car and so actually has zero camber set.

 

[niclake13]

Just to see if I'm following this correctly... for a car like the BMW M3, I probably don't need too much camber in it, due to the overall good handling/looseness of the car already... am I following this right?

 

[Mt. Lynx]

Well, like Scaff said; that depends very much on how you drive!

 

[GEETOWN_DRIFTER]

i like to use about 2.3front, 2.0 rear, that works for me. but on some i'll go all the way 7.0 with it,it doesnt help for driftin but it looks kool while ur doin it...lol

 

[sucahyo]

ignore

 

[sucahyo]

BTW - The picture of my Clio V6 (blue one) used to show camber is in fact a shot taken before I tuned the car and so actually has zero camber set.

I see. Interesting, you start from zero camber too . And 1.4º is for car front body roll angle, not wheel camber (my description is misleading ).
If the car is untuned, then the body roll should be lower when tuned.

Just to see if I'm following this correctly... for a car like the BMW M3, I probably don't need too much camber in it, due to the overall good handling/looseness of the car already... am I following this right?

If you are not sure, try to measure the angle of your car when turning (you can zoom it in photomode?). If it measure less than 1 degree, you won't miss the cornering traction much if you use zero camber. We use low camber not because the car is handling good, but because the car has low body roll.
In GT2 using zero camber is better than using 0.5 camber.
GT2 BMW 328Ci measured as:
3.0º front, less than 1.0º rear on 2/2 spring rate 150/150 ride height
1.1º front, less than 1.0º rear on 8/8 spring rate 110/110 ride height

i like to use about 2.3front, 2.0 rear, that works for me. but on some i'll go all the way 7.0 with it,it doesnt help for driftin but it looks kool while ur doin it...lol

Japanese drifter earlier use it too to make the rear slide easier on low power car, they call it demon camber (mentioned in FR Drift Guide - By Boundary Layer and Swift). But I am not sure how much they use it.


This is a nice explanation on how we set up camber in real life. This is reference that make me believe that camber should be the set according to the amount of body roll. It also say to use camber only if all else fail, so, I start my tuning with zero camber.

The two main points about oval track handling are turn-in and Corner speed, turn-in can normally only be evaluated by driver feel and corner speed by a stopwatch.
Start by setting up the camber and tyre pressure with the aid of a tyre pyrometer, they can be bought for around £100 if you can't borrow one, maybe not cheap, but what did you pay for the car?
Temperatures should be taken at the inner edge, the outer edge and the centre, as soon as possible after the car has stopped. The inner and outer edges should be the same when the camber is correct, too much negative camber will make the inner edge warmer and too much positive the outer edge is warmer, for tyre pressure the centre should be the same as the average of the inner and outer edges, (but then you've already set the camber and got them the same, right?).
Although if the outer edge is warmer you could also reduce body roll. After arriving at a setting for tyre pressures and camber you can now start to play with the turn-in, drivers vary on what they like so this one is pretty much up to you! To alter this you use tracking settings (toe in and out) or change the relative roll stiffness between front and rear, but remember only change one thing at once. If possible it is better to change antiroll bars than springs or the car may not work on a bumpy track, and don't forget, changing the angle of roll alters the camber, so you'll need to check this again! As I said there's a lot of variables in suspension technology!
As a guide, to make the car understeer less stiffen the rear or soften the front or a reversal to reduce oversteer. The limit to roll stiffness is when the car starts to lift a wheel, then you have car too far and will have to look at other methods, you cannot tune the suspension of your now 3 wheeled car.
Tracking adjustments are another way of altering turn-in, increasing toe-in will give understeer and toe-out will give oversteer. While you can make a car f better by adding camber or reducing tyre pressures it is at the expense of total grip levels and should not be done except maybe as a last resort to fine tune, if all else has failed.
If you have adjustable shockers, all you can really do is play and see what feels right, but start from soft, and gradually increase until it feels right and do one end at a time.
If the car is heavy in a turn you can reduce caster, but be careful as too little can make the car very unstable in a straight, obviously on a short tight track this will have little importance though.
As a rough guide: to reduce understeer; increase weight transfer at rear by increasing rear roll stiffness, reduce weight transfer at front by reducing front roll stiffness, reduce toe-in, use wider front tyres, increase front tyre pressure (a last resort only).
To reduce oversteer; reduce weight transfer at rear reducing rear roll stiffness, increase weight transfer front by increasing front roll stiffness, increase toe in, use wider rear tyres, increase rear tyre pressure (a last resort only)
The car feels as good as you can get it, you want to go on and thrash everyone in the next race right? Wrong the next step is simply to drive it faster and start again, there's no conclusion to this one, as the handling gets better you just increase the driving speed, see which end is losing grip first and start again, it just becomes harder to improve and you gain less, but it's always possible improve it!

And this is the reference that make me believe camber shouldn't be bigger than body roll angle. That is, to make the tire make flat contact to the road, a 1.2 degree body roll should have 1.2 degree camber max.

Put the front end of your A-body up on jackstands. Now that the wheels are at full droop, note how the tops of the tires lean in towards each other (lots of negative camber). Now put a jack under one lower control arm and slowly jack it upwards. Watch the tyre/wheel as you do this, you will see the tire go from leaning inwards at the top all the way to leaning outwards at the top as you jack the control arm up through its range of travel. That change prevents the tire from staying flat on the road and gripping with all its tread width - this is an extreme example of camber change with suspension travel and it is not good suspension geometry, it is absolutely horrible suspension geometry! On any well-engineered suspension this camber change should be undetectable by eye, it takes a camber gauge to measure it on any of the Mopar's I've owned, for instance.

An even quicker and easier way to see the poor camber curve on the GM A-bodies is to get a buddy to drive one over a speed-bump and watch the camber angle on the wheel/tire as it goes over the bump. This is how I first noticed how bad the geometry is! You can see the tops of the tires lean outwards as the speed bump pushes the suspension up into the wheelwells.

When you go into a turn with a GM A-body the outside front tire does more of the work than any of the other three tires (the weight transfers to the outer two tires, so the inner two are lightly loaded and don't do much work; also these cars carry more than half their weight on the front wheels so it is the outside front tire that provides a majority of the grip needed to make the turn) and this is the very tire that is being tipped over by the camber change, reducing its grip at the very moment it is being asked to provide all it can. To get maximum lateral grip the tire MUST be flat on the road or have very slight negative camber, and that is the reason for all the interest in re-engineering the front suspension on these cars using taller spindles, etc.

I do some measurement on car in BMI Drift Bible, this is what I got.

Car                    front   rear
===================================
Kei Office S14 roll    3.3     2.4
Kei Office S14 camber  2.8     2.5
Altezza roll           2.3     1.2
NSX roll               3.6
Porsche GT3? roll      1.9     2.8
Supra roll             3.6     3.3

It's interesting that in real life RR also have bigger rear body roll.
Altezza which is known for understeer having double front body roll.
The camber of Keiichi Tsuchiya's car has camber closely the same as body roll angle.

 

[Scaff]

I see. Interesting, you start from zero camber too . And 1.4&#186; is for car front body roll angle, not wheel camber (my description is misleading ).
If the car is untuned, then the body roll should be lower when tuned.

The zero camber starting point does very much depend on the car in question, sometimes I do and sometimes I start with the default setting.

In regard to body roll being lower when tuned, that does of course depend on the default settings and the track being tuned for. In the case of the Clio V6, as I was tuning for Deep Forest I actually reduced both the damper and spring rates for the car. As the default settings are too firm for my driving style and this track in addition to minimal changes to the ride height, as a result tuning in this case incresed body roll.

If you are not sure, try to measure the angle of your car when turning (you can zoom it in photomode?). If it measure less than 1 degree, you won't miss the cornering traction much if you use zero camber. We use low camber not because the car is handling good, but because the car has low body roll.
In GT2 using zero camber is better than using 0.5 camber.
GT2 BMW 328Ci measured as:
3.0&#186; front, less than 1.0&#186; rear on 2/2 spring rate 150/150 ride height
1.1&#186; front, less than 1.0&#186; rear on 8/8 spring rate 110/110 ride height

Japanese drifter earlier use it too to make the rear slide easier on low power car, they call it demon camber (mentioned in FR Drift Guide - By Boundary Layer and Swift). But I am not sure how much they use it.

An excellent starting point, but I still personally find that a degree of trial and error is required in fine-tuning camber settings.

This is a nice explanation on how we set up camber in real life. This is reference that make me believe that camber should be the set according to the amount of body roll. It also say to use camber only if all else fail, so, I start my tuning with zero camber.

This explanation should also carry a warning, its written with a very specific type of track in mind.

The two main points about oval track handling.....

Tuning for oval tracks is a very specific art and can not be directly applied to circuit tuning, oval tracks tend to be limited in the nature of corners (some oval consist of identical corners) rather than the wide range of slow and fast corners found on 'street' circuits.

And this is the reference that make me believe camber shouldn't be bigger than body roll angle. That is, to make the tire make flat contact to the road, a 1.2 degree body roll should have 1.2 degree camber max.

Again a good starting point, but the issue is that not all corners will cause the same level of body roll (unless you are talking about an oval track with identical corners which are taken at the same speed and with the same line every time). A high speed sweeper will generally cause less body roll than a low gear hairpin corner; also the amount of body roll is not constant throughout a given corner (turn-in, corner entry, apex and corner entry can all result in different degrees of roll).

As a result body roll and the resulting suspension changes (including camber) need to be addressed for each track and the nature of the corners found. A setting that works for the final corner at Tsukuba may not be ideal for the first corner at Tsukuba.

Its one of the issues I have with 'formula' tuning and why I believe that a set-up needs to be crafted for each car/circuit/driver combo.

Don't get me wrong, what you have outlined here is an excellent starting point, but it is just that, a starting point.

Regards

Scaff

 

[sucahyo]

The zero camber starting point does very much depend on the car in question, sometimes I do and sometimes I start with the default setting.

In regard to body roll being lower when tuned, that does of course depend on the default settings and the track being tuned for. In the case of the Clio V6, as I was tuning for Deep Forest I actually reduced both the damper and spring rates for the car. As the default settings are too firm for my driving style and this track in addition to minimal changes to the ride height, as a result tuning in this case incresed body roll.

I see.

An excellent starting point, but I still personally find that a degree of trial and error is required in fine-tuning camber settings.

Don't get me wrong, what you have outlined here is an excellent starting point, but it is just that, a starting point.

Yes, I hope more people will start put more attention to camber.
I mean, It's a pity if you have the tool to see how much your car roll in every corner with great detail (photo mode), and not use it to tune your car. And too many of you ignore the fact that RUF have more rear roll than front (I can be wrong, but it is true in GT2 and BMI drift video). And please aware that there are other car beside RUF that have heavier rear.
People tend to use 2.0/1.0 for RUF camber, which is questionable. Too many people rate this car as understeer, and yet people make it more understeer with worng camber value. The one who don't use very oversteer suspension setting. If they decide to use camber, they should atleast using slightly bigger rear.

 

[Scaff]

I see.

Yes, I hope more people will start put more attention to camber.
I mean, It's a pity if you have the tool to see how much your car roll in every corner with great detail (photo mode), and not use it to tune your car. And too many of you ignore the fact that RUF have more rear roll than front (I can be wrong, but it is true in GT2 and BMI drift video). And please aware that there are other car beside RUF that have heavier rear.
People tend to use 2.0/1.0 for RUF camber, which is questionable. Too many people rate this car as understeer, and yet people make it more understeer with worng camber value. The one who don't use very oversteer suspension setting. If they decide to use camber, they should atleast using slightly bigger rear.

Would quite agree with what you have said in regard to RR cars (and some MRs as well) that with rear weight bias needs careful attention when tuning. That said in regard to tuning cars of this nature I would not agree that its an automatic camber bias towards the rear.

I would argue that front and rear camber need to be looked at seperately, and that while a car with a strong rear weight bias may need a greater camber increase from standard at the rear than the front, it doesn't automatically follow that the rear camber should be greater than the front (if that is what you are saying - its not 100% clear).

Remember that while cornering the front outside tyre is still going to be doing the majority of the work and as such the front tyres are still the ones that will generally benefit more from camber adjustments.

In the real world high camber settings (and by that it generally means above 3.5 at the front and 2.5 at the rear) at the back can cause very sudden breakaway at the rear, not what you would want in a rear engined car.

Of course even after saying all of the above, if using more rear camber than front works for a driver on a car, then use it.

Regards

Scaff

 

[sucahyo]

For front wheel, there is caster. I don't know GT engine implement caster or not, wether they the same for every car or not. But this is what I think:
- at front wheel 0 degree turning, the amount the wheel angle to the road is the same as the car roll.
- at front wheel 90 degree turning, the amount the wheel angle to the road is the same as the car pitch plus caster angle.
- at front wheel 1 to 89 degree turning, the amount the wheel angle to the road is between the above.

About the camber angle, yes, even on GT2 using 2.0 for rear for RR car using 8/8 spring rate would be too much. Using 2.5 for front is excessive for RR car.

About camber angle for car with heavier rear, from what I test:
- FR car have front roll about 3x to 0.5x rear roll
- FF car have front roll about 2x rear roll
- MR car have front roll about 1.5x to 0.5x rear roll
My conclusion:
- car which have front roll 1.5x rear roll have perfect distribution
- car which have front roll more than 1.5x rear roll have heavier front
- car which have front roll less than 1.5x rear roll have heavier rear

Only some car have more rear roll and should need higher rear camber (4 out of 29 car I test).

About higher rear camber for RR car, I got some picture of real life porsche car, some of them use higher rear camber. So, why don't we copy them?









http://www.seriouswheels.com/top-2005-RUF-Porsche-RT-12-Turbo-05.htm

 

[Scaff]

For front wheel, there is caster. I don't know GT engine implement caster or not, wether they the same for every car or not. But this is what I think:
- at front wheel 0 degree turning, the amount the wheel angle to the road is the same as the car roll.
- at front wheel 90 degree turning, the amount the wheel angle to the road is the same as the car pitch plus caster angle.
- at front wheel 1 to 89 degree turning, the amount the wheel angle to the road is between the above.

About the camber angle, yes, even on GT2 using 2.0 for rear for RR car using 8/8 spring rate would be too much. Using 2.5 for front is excessive for RR car.

About camber angle for car with heavier rear, from what I test:
- FR car have front roll about 3x to 0.5x rear roll
- FF car have front roll about 2x rear roll
- MR car have front roll about 1.5x to 0.5x rear roll
My conclusion:
- car which have front roll 1.5x rear roll have perfect distribution
- car which have front roll more than 1.5x rear roll have heavier front
- car which have front roll less than 1.5x rear roll have heavier rear

Only some car have more rear roll and should need higher rear camber (4 out of 29 car I test).

About higher rear camber for RR car, I got some picture of real life porsche car, some of them use higher rear camber. So, why don't we copy them?

Good stuff (once again) and as I said at the end of my last post, if it works use it. But as you have shown, so use higher rear camber others don't., so you still have to set it up for the car and driver.

Regards

Scaff

 

[Mt. Lynx]

You also has to consider what track you are running at, especially the surface. If it&#180;s very bumby, &#225; la N&#252;rburgring, too much camber may send the car somewhat sideways even when driving in a straight line. Camber is always a compromize between straightline stability and corner stability. Just like toe.

 

[sucahyo]

Good stuff (once again) and as I said at the end of my last post, if it works use it. But as you have shown, so use higher rear camber others don't., so you still have to set it up for the car and driver.

Ok.
I think if the car is understeer increasing front camber do not reduce the understeer, if the camber is already the same as body roll angle. And body roll angle for average tuning (more than 6/6 spring) usually lower than 1.5 degree.

You also has to consider what track you are running at, especially the surface. If it´s very bumby, á la Nürburgring, too much camber may send the car somewhat sideways even when driving in a straight line. Camber is always a compromize between straightline stability and corner stability. Just like toe.

Yes, that is the sign of excessive camber.
That is also the reason why I don't use camber these days, if you drive smoothly, your outside tire will gain more traction from camber. But if you drive rough (using digital controller), the outside tire will loose traction if you correct the steering in the middle of the corner. To compensate zero camber I use harder spring rate and lower ride height.

BTW, if you are interested (and still have GT2) why don't you all join setup vs setup thread? we are currently trying to tune cobra coupe in rome night. You can comment on my tuning on jaguar xjr too (no camber).

 

[Leonidae]

sunny.. I always do a base setup that has 3.0' camber front and 1.5-2.0' rear, and start adjusting the suspension from there towards better one..💡

 

[sucahyo]

sunny.. I always do a base setup that has 3.0' camber front and 1.5-2.0' rear, and start adjusting the suspension from there towards better one..💡

Try comparing your car handling with no camber, maybe on yellowbird, and see if it increase oversteer or understeer.