I’ve been trying to figure out how to tune cars. I’ve read/watched all the “tuning guide” material I can find, but I have some specific questions that I’m still not clear on:
Camber: is there such a thing as too much? I play without tire wear, so that’s not a factor, but does cornering ability go back down after you pass a certain tipping point? Is there any way to know that tipping point, other than extremely lengthy trial and error (like maybe the telemetry)?
Caster: what does this do, for driving dynamics in the game? I know what it does in real life, but steering feedback/weight is not something I’m concerned with in the video game. I know there’s such a thing as too low (which would ruin straight-line stability), but is there such a thing as too high, and if so, what happens if I turn it up too high?
Springs vs. ARBs: The relative stiffness of the front and rear springs changes the oversteer/understeer balance. So does the relative stiffness of the front and rear ARB. If I have a car with too much understeer, how do I know whether to soften the front springs, front ARB, or both? Also, how do I know when to soften the front vs. tighten the rear?
Bump stiffness: Is there such a thing as too low? What happens if you cross that point?
Rebound stiffness: Is there such a thing as too high? What happens if you cross that point?
Tire pressure: Everyone says you want 32-35 psi when the tires are up to temp. That’s a pretty big range, considering the settings are at 0.5 psi intervals. Do I want 32, 35, or somewhere in between?
Thanks in advance for any responses. I know the answer to any of these can be “trial and error”, but a lot of these differences are hard to perceive, other than looking at the lap times themselves, and the lap times themselves depend on how well I drive as well as how well the car is set up. So I’m hoping I can increase my understanding through this, because I don’t really want to spend dozens of hours just test driving cars in order to get them set up right.
“How to” is the holy grail question of set-ups. I’m going to answer quickly because the long version would be . . . too long.
Camber - yes, there is such thing as too much > you’ll have reduced grip, in theory. Never personally tried any camber greater than -2.5 though. Front generally demand more camber.
Caster has the effect of loading up the outside front tire and lifting the inside rear. If it is too high, the front end may “bite” too aggressively in tight corners.
This is a big one so I’m going to skip.
Yes there is. In real life you have “slow” & “fast” bump. In FM5, it seems we only have “slow” but many use it as a “fast” damper, i.e. very low value - good for riding curbs.
Yes there is. In real life you get suspension “jacking” and bottom out, especially combined with low bump. In FM5, there is no consequence to bottoming out. #4+#5 with stiffer spring rates seem to work well to giving sense of smoothness and stability.
It is true, I personally target about 33~34psi. Heavy cars or high profile tires benefit form higher pressure; lighter car or low profile tires can handle lower pressure.
You haven’t asked about the differential . . .
If you are looking for templates you can use for FM cars, I think they are out there. If you want to learn HOW everything works so it can be applied to ANY racing simulator, that is a very very long journey with many wrong turns and blind alleys.
Good to know. I still would like to know how, other than endless trial-and-error, complicated by the fact that I never drive the car exactly the same in any two laps, to figure out exactly what camber setting is right for any given car. I’d taken to using -2.5 front and -2.0 rear as a default, but sometimes I’ll look at someone’s open source tune that’s faster than mine, and find out they’re using more like -3.5.
Biting too aggressively is bad? I don’t think I understand your meaning.
It sounds like you’re saying I’d be best off using the absolute mininum bump and maximum rebound, in FM5. If that’s true, then it’s good news (easy to remember, difficult to mess up!). But is it really that easy? Open source tunes don’t seem to generally use the absolute extremes.
Makes sense, thanks.
Yeah, didn’t take the time yet to figure out how to formulate my differential questions. I’ll add some, at some point.
Well, I don’t currently have any other racing simulator(s), so I guess I’m not very concerned with anything but FM5. I just don’t like the feeling that the cars will never be as good as they can possibly be, because I haven’t cracked the code of how to tune them as well as some more expert players have. They’re obviously better drivers than me, and they probably always will be, but I’d like to at least be in just as good a car as they’re using.
Generally between -2.0- -4.0 some cars can be higher lower. But that’s a good range.
5.0-7.0
Roll bar is more for the lateral movement if you are suffering under/over steer when moving laterally. Adjust accordingly.
most setups run between 1.0 and 2.0
most between 9.0 and 12.0
around 28-29.0
This will vary from car to car and track to track, but MOST “good” setups will fall in that range. Their are exceptions to every rule, these are just pretty good ranges.
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Yes there is “too much” it is slightly trial and error, My way is listening the tire tires, I attack mispeed corners, or if I’m going track spesific build, I listenthe tires at most typical corner for the track, The less I hear tire noises, the closer I am the “sweet spot” When tire noises are quite minimal, it’s time to do couple fast laps, and go slightly more, or slightly less camber try which feels better or is other clearly faster. Most of the times I’m runing -3.5 to -2.5 front, and -3.1 to -2.2 rear. If I’m having really narrow tires, it tends to be higher camber. Also if I’m runing really soft ARB’s it tends to be slightly higer than on stiffer ARB’s.
Personally I havn’t noticed too much difference, How ever I tend to lower the caster for AWD and FWD, and increase for RWD. Somehow it just feelsmore responsive. How ever that is not “set in stone” and there is some cars that might differ.
I keep looking at suspension telemetry on this one, I want a lot of movement on the “bars” but they may never EVER fill up completely, even if you have to avoid another car, and run across high kerbs. That would be bottoming out, which may cause total loss of control, (also very low ride height may contribute on that). Therefore, if you are close to bottoming out, and need to soften, start with ARB’s if that causes bottoming out, stiffen springs. (or raise ride height.)
Most cars, yes, although you will get away next to non existant settings. The car might get bouncy over bumps specially the front end of car. (might be other way around in mid engine cars, not sure as I prefer not to use those)
Yes, while going over small bumps the car might start braking traction as the dampers don’t let the wheels exted out as much/fast as needed
4&5, Bugatti circuit back straight braking zone is good place to test this
Sometimes it is that crucial 0.5 psi that makes or brakes the tune. Me and my friend were once tinkering with a car, constantly opensourcing eachothers. he tested my tune, which I considered being at it’s best, he tried it, liked it, then suddeenly he just tells me to drop 0.5 psi out on rear, and add 1.0 on front tires, and I try it, and car that was slightly loose before it suddenly started driving like it would have been on rails.
If your front tires “Bite” hard enough, your inside rear tire may lift, losing roughly 45% grip of the rear end, which might result in snap oversteer, and if this is combined with running over a kerb at the same time with inside front tire, it might result on lifting up on to 2 wheels or even to extremely unlikely, but possible rollover.
You turn in to the corner with a lot of steering. The car turns in fine initially and as the car settles the rear end comes out, causing mid-corner oversteer. Now opposite can also happen; mid-corner understeer.
So my recommendation for the order of starting from scratch tuning/set-up is as follows (this approach can be applied on ANY racing sims):
Springs: stiff enough to support the weight of the car, soft enough to absorb the bumps (easier said than done . . . )
ARB: stiff enough to SUPPLEMENT springs for cornering, soft enough for maximum cornering grip. Front-Rear difference for cornering balance.
Bump: stiff for response, soft for grip/compliance
Rebound: stiff for stability, soft for grip/compliance
Diff: stiff for high speed cornering, soft for low speed cornering
Brake balance: % number indicates REAR brake power, not FRONT. High % = corner entry oversteer & unstable. Low % = corner entry understeer but stable.
Camber
Caster
Tire pressure: fine tuning for front/rear balance
Then, if you change one of the items above, all of the setting below may have to be adjusted.
eg. if you change ARB in sigificant amount, you probably have to adjust for the changes in #3~#9. If you make changes to #5, should check #6~#9. etc.
The order of #6, #7, #8 may vary from one person to another. If you develop a system, then at least you’ll be consistent and have a routine to follow & easier to troubleshoot.
I run into the understeer version of this a lot, seemingly due to a variety of setup errors. The car turns in okay, but then pushes instead of continuing to rotate through the turn. It seems to me like this is sort of a default “your tune still needs work” behavior. I recognize that this perception is partly because I haven’t learned to interpret every aspect of the feedback the car is giving me yet.
Really? Seems to me like stiff provides more grip. The car I’m tuning now started holding turns a lot better when I went up 15% from default (9.3 front 8.5 rear) to 11 front 10.1 rear.
Accel, decel, or both? Also, I don’t see why decel shouldn’t be set to 0, always. What’s the advantage of having decel diff above 0?
Developing a system is exactly what I’m working on doing. Once I’ve got a really good '05 Impreza, I’m hoping I’ll be able to get the next car pretty good in half the time, or less.
That’s for accel. Decel is “usually” lower than accel.
In a low powered cars where wheel spin is not an issue, 0 differential is fine.
In high g cornering, the inside tire will always be lightly loaded than the outside. If the load on the inside tire is low enough, it will slip = overall lower traction. Having decel, or “coast” differential, will improve traction and control during this phase. If used incorrectly, it can make the drive/handling worse . . . far far worse.
In FF, having a touch of differential (3~8%) could be the difference between a fun car or an aggravatingly understeering car.
In RWD, a good accel/decel diff settings will allow the driver to invoke mid-corner understeer/oversteer at will using the throttle only > that’s heaven. Being able to adjust the direction of the car WITHOUT using steering is very useful since more steering = speed scrub.
At slow speed, high rebound can give more grip. For fast speeds, high rebound returns the wheel/tire more slowly therefore it loses contact with tarmac. If the car has downforce then rebound has less of an impact on traction since aero is pushing down on the tires.
It also depends on how much bump you have. If bump is very low (3.0 or less), then high rebound is necessary to dissipate the total energy in the springs.
If one uses the bump suggested by Forza, then 10.0 or more rebound is not advisable as it will be too stiff.
There are certain techniques of setting up the dampers which I will not go into details here but any simulation WITHOUT fast/slow dampers can benefit from low bump and high rebound.
Upon encountering something like this, it is best to first clearly DEFINE the problem by having a checklist. Solution also differs depending on the drive type, FF/FR/RR/MR or AWD. Also don’t forget to take into account one’s driving style and avoiding overdriving the car. FF cars require different line than FR, for eg. Other than the spring rates, every other set-up parameters are different even though the weight% is the same for both cars. Without knowing the drive train, it is not advisable to suggest a solution for the understeer.
For example he mentions a temp spread from inside edge to outside edge to determine when you “may” have the right level of camber.
Even once you find where you have that temp range it is worth testing a little more camber and a little less camber to see what works best for any given car.
Just tried using the temp distribution telemetry to tune camber and tire pressure on the car I’m currently trying to set up (Subaru Impreza '05 for B class), and it seemed to work great. Ended up with lower pressures than I had expected, higher front camber and lower rear camber, in order to get a smooth inner > middle > outer distribution on both front and rear. The car handled much better afterward than before (when I had set these to more or less average values from open source tunes I’ve liked for other cars). So this method is definitely a keeper for me, thanks.
Just want to give a quick shout out to those that answered his questions. The answers in this post are literally all u need to get a good setup. I was going to post what I do but it has already been said better than how I would have said it. I hope other people come on here and take the time to read what you have posted in response to the op.
I got the 05 Impreza to where it has good grip, but is biased a bit toward understeer.
Other peoples’ tunes of this car and similar cars (other Imprezas, Evos) tend to correct out the understeer with soft front/stiff rear, and this does make the car feel like it turns better.
But it makes me slower around the track. Lap after lap, my tune feels like it’s pushing just a little, and whatever open source or shared tune I’m trying feels like it rotates better, and yet my tune’s a full second faster. In at least a few cases, these are tunes with the exact same parts.
My question to you guys who are good tuners, is do you do what the lap times tell you, or do you do what feels more like the right setup?
That’s the million dollar question. Is your driving style wrong or is the setup wrong. All of these ideas on how to setup a car or what is the correct way to setup a car may be wrong with ur driving style. Personally what I did when improving my tuning ability was use what info others gave me and made my own Frankenstein tune that fit me. Others may or may not like it because we all drive differently. I would suggest go with what feels good and what is getting u your lap times. Just remeber like hlr said that normally a very fast car can be very unpredictable so that’s y u aren’t hitting the lap times u want. Once mastered an unpredictable car setup correctly can be incredibly fast. For lobbies consistent laps are the better direction to go because u rarely always get the preferred racing line.
Softer front roll= better turn in, higher rear roll=better turn in, that why you feel the rotation better. Your slower around the track, due to another setting elsewhere. If it’s pushing springs more than likely need adjusting.
Juggernauts last post is terribly misleading. A lb car tuned for hotlapping can be consistent and easy to drive. No different than a “lobby car”. Some lb cars are just extremely hard to drive.
I do agree on some degree, There is handfull of cars that are very good to drive, while pulling top LB times. but again there is driving style differences.
A friend of mine (who prefers small understeer in lobbycar) once built a “good drift car”, And other friend of mine used that drift car, beat his own best lap on some track, while racing the original builder of that said drift car while the original builder of the said drift car was in his LB tuned car for the said track. That is how much some driving styles differ. and therefore a tune and build need to differ too,
AWDs are very flexible because one can tune it to drive like a FWD, RWD, or . . . AWD. They can be extremely agile which is the main reason they are being used on rallys.
For AWDs, I prefer to still set up the spring/arb/dampers as if it was any other car (+ small bias towards FWD set-up).
AWDs always require different driving technique. If you drive AWD like a RWD or FWD, you will lose time. One has to use AWD, in my opinion, very aggressively since acceleration traction is split to 4 wheels instead of 2.
Differential plays a key role in a successful AWD. My recommendation is the set-up the suspension without soft front then use differential (with some help from ARB) to balance it.
I personally go “half way” around evrything
Priority list for.
For race car / lobby car
Stable under all conditions (stability = consistency)
Reasonably fast
Predictable, was it oversteer or understeer, preferrably small entry understeer, but I want to be able to induce oversteer at any time if I want to.
For hotlap car
Fast
Somewhat predictable
Fast
Faster
Ignore that predictability + FASTER!
Main difference.
For hotlap car I couldn’t care less if I can make only 1 fast lap in test session of 20 laps, All I care is how fast that fast lap actually was.
In other words, I would probably end DNFing in average lobby 4 lap race if I would enter with hotlap tune, just because I would be spending so much time on grass. how ever if that would be race of let’s say 30 laps, I would highly likely hold the fastest lap time, even though I would be last car to finish the race.
If I enter in race car, I would probably be on podium, or pretty close to it, Just by waiting for other drivers mistakes.
Although, I have to say, I run with no assits. Which is part of the reason why that hotlap car so hard to drive.
^^^^^^^^^^^^^^HUH? You tune both cars to be consistent. If you are running inconsistent laps your driving is bad. You should be able to turn consistent laps that reflect your ability. If you are all over the place lap time wise it’s more driving than tune.