Hi. I have the lfs demo . I m experiencing some strange front wheel drive car (XF GTI) behavior when I m entering a corner trail braking or sometimes left foot braking until the apex the car is neutral and then when I begin to lift of the brake and start applying the gas the car is starting to oversteer.I m expecting understeer. I dont know if it s a setup problem. I m using some Team inferno setups and they should be good.

its how the Team Inferno people get such good times with their setups - they've manipulated the suspension so that it has oversteer, not understeer - basically giving the rear of the car very little grip to get round quicker. Just counter it with a bucketload of power a tad of opp. lock.

All setups are good for the person who made it.

If you get a set that does something you don't like or can't get used to trying tweaking it a little to suit you more.

Quote from vlado_skopsko :

Hi. I have the lfs demo . I m experiencing some strange front wheel drive car (XF GTI) behavior when I m entering a corner trail braking or sometimes left foot braking until the apex the car is neutral and then when I begin to lift of the brake and start applying the gas the car is starting to oversteer.I m expecting understeer. I dont know if it s a setup problem. I m using some Team inferno setups and they should be good.

Maybe because of a locked differential, or high locking.

Quote from hinirags :

Maybe because of a locked differential, or high locking.

That is the reason.

To reduce that phenomenon, harden up in small steps the rear antiroll bar, till you can control the corner exit oversteer.

Allso you can try use the gas in a smother way and reduce the braking at the same smooth way.

If you want just a realistic setup to play with, get rid of the locked diff and use a clutch pack with less than 50% locking power. Also you will have to re adjust at least front and rear antiroll bars cause in order to make the locked diff usable, setup makers use much harder antiroll bar at the front and this is not what you want when you have a normal diff

well actually I had this problem too, and its quite easy to fix it WITHOUT changing setup. I found out that I release brake too fast which caused sharp weight distribution change and as the set already has quite a bit of oversteer it sends the car into slide. Honestly, just release it gently. it works

Quote from [RF]-art555 :

well actually I had this problem too, and its quite easy to fix it WITHOUT changing setup. I found out that I release brake too fast which caused sharp weight distribution change and as the set already has quite a bit of oversteer it sends the car into slide. Honestly, just release it gently. it works

Also, either

A) Dont brake and turn
and/or
B) Set there to be more brake bias at the front

Quote from J@tko :

A) Dont brake and turn

Sometimes you have to when racing...

Quote from J@tko :

B) Set there to be more brake bias at the front

This helps only rwd cars which don’t have much coast locking at the diff… or helps generally if the rear brakes are so strong that the rear end looses traction during braking but that is not the case here.

Thank you all for your suggestions.It would be much better if I make the setup that corresponds to my driving style. This is strange because i dont have any oversteering problems at the corner entry when I m braking and all weight is at the front and then when lift the brake its starts. So I dont think that putting brake bias at the front will help. I m trying to be as smother as possible. Im driving with lock diff because its faster that way.KAYND if I harden the rear antiroll bar wouldn't it lead to more oversteer?? THANK YOU AGAIN

Quote from vlado_skopsko :

Thank you all for your suggestions.It would be much better if I make the setup that corresponds to my driving style. This is strange because i dont have any oversteering problems at the corner entry when I m braking and all weight is at the front and then when lift the brake its starts. So I dont think that putting brake bias at the front will help. I m trying to be as smother as possible. Im driving with lock diff because its faster that way.KAYND if I harden the rear antiroll bar wouldn't it lead to more oversteer?? THANK YOU AGAIN

when the physics will be less bugged, it will certainly increase oversteer (more likely decrease understeer) to stiffen the rear antiroll bar. But now, it is the opposite (at least under throttle).

This is not a physics bug…
When you harden up the rear anti roll bar, indeed you ad oversteer.
In that way you remove vertical force from the inside rear wheel and you add vertical force to the inside front wheel which if you had a normal differential with a med to low coast setting (fwd), would increase front traction.
When you have a locked diff, in order to steer you need to load the one of the two driven wheels with a much grater force so the other one (the inside) does not resist to the turn, that’s because both wheels have the same angular velocity (locked diff) but they have to take different tracks while turning and that means, the inside which is lower loaded should keep spinning regardless the shorter distance that covers from the inside line.

The only physics problem here seems to be that one wheel, generates the same lateral and longitudinal force as two wheels, when loaded with the same vertical force… that makes the locked diff setup fast by using only the outside driven wheel. (Mainly at the fwd cars)

The physics aren't bugged. The stiffer end will roll more, decreasing grip at that end. With a locked diff however, massive understeer is generated from tyre scrub, the additional weight transfer reduces the load on the inside tyre, reducing the understeer the diff generates.

Edit: slow, shoudn't start browsing the web half way through replying

Hell yeah!!! I was faster than the hand of mod

do you also have those problems if you dont get on the power after trailbraking ? it might be that youre simply braking too hard and once you get off the brakes the front tyres regain traction and pull you around

Quote from kaynd :

This helps only rwd cars which don’t have much coast locking at the diff… or helps generally if the rear brakes are so strong that the rear end looses traction during braking but that is not the case here.

Does it - oh, sorry then

Ure obviously more technically minded than me

sounds to me like a problem of too much weight transfer for your driving style. during trail braking, the weight shifts to the front of the car, but the front tires are doing double duty, both braking and turning, so they can't turn in very hard. as soon as you lift off the brake, the front will have more turning grip available, and will turn in quite hard, causing the rear end to whip around. this can be very handy in some situations. for example, it can save you from plowing off the track when you brake too late.

as suggested, being a little smoother coming off the brake might help, but if you'd rather not change your driving style, try increasing the front bump and/or increasing the rear rebound. this should reduce the weight transfer to the front and give you more predictable steering. but don't use too much or you'll end up with understeer.

Yep Evilgeek is right - one click of front bump and a click of front spring rate should help minimize this effect.

Left foot braking while keeping a tiny bit of throttle on at corner entry can also help limit this effect.

Thank you for explaining me how the anti roll bar works with the locked diff .Yes I have the oversteer even if I dont apply the throttle so it might be that the regaining of the front wheels traction is causing that. I will try to modify the setup. Thank you all for pointing this to me.

Quote from vlado_skopsko :

Thank you for explaining me how the anti roll bar works with the locked diff .Yes I have the oversteer even if I dont apply the throttle so it might be that the regaining of the front wheels traction is causing that. I will try to modify the setup. Thank you all for pointing this to me.

It's caused by a soft front end allowing the front springs (and ARB) to compress too much under braking. As they do this they store some energy within them and as you release the brake this energy is released. As the energy is being released it a) raises the front of the car back up as the springs decompress and b) some of that force goes to pushing the front tyres into the track, resulting in a sudden increase in front end grip, hence the oversteer.

Quote from kaynd :

This is not a physics bug…
When you harden up the rear anti roll bar, indeed you ad oversteer.
In that way you remove vertical force from the inside rear wheel and you add vertical force to the inside front wheel which if you had a normal differential with a med to low coast setting (fwd), would increase front traction.
When you have a locked diff, in order to steer you need to load the one of the two driven wheels with a much grater force so the other one (the inside) does not resist to the turn, that’s because both wheels have the same angular velocity (locked diff) but they have to take different tracks while turning and that means, the inside which is lower loaded should keep spinning regardless the shorter distance that covers from the inside line.

The only physics problem here seems to be that one wheel, generates the same lateral and longitudinal force as two wheels, when loaded with the same vertical force… that makes the locked diff setup fast by using only the outside driven wheel. (Mainly at the fwd cars)

Quote from Bob Smith :

The physics aren't bugged. The stiffer end will roll more, decreasing grip at that end. With a locked diff however, massive understeer is generated from tyre scrub, the additional weight transfer reduces the load on the inside tyre, reducing the understeer the diff generates.

Edit: slow, shoudn't start browsing the web half way through replying

Have I talked about locked diff?
I did some tests with clutch pack, and the same things happens : stiff front arb, and soft arb at the rear seems to result in more 'oversteer' under throttle. With open diff there is no traction so I did not notice clearly what is happening, but oversteer on throttle with this setup technic for arb seems to work too with clutch pack.
And, if it is not a bug like you are saying, why is it not used IRL? I've heard that on "slipping" surfaces, the % locking of the differential is close to 100% (maybe it is not like if there is no diff, but should be close in term of handling (?) ), so do they use very soft rear arb to exploit this?

It depends on the locking percentage at the dif…
As long as the differential gives more torque to the more loaded outside wheel, you are going to have oversteer at the corner exit with throttle.
The more you load the outside front wheel the more oversteer while pressing the throttle you get…

And who told you that IRL they always use stiffer ARB back than in the front? It depends on the weight distribution; what we can consider as soft or hard at the front or the rear of the car.
IRL it depends on the balance you want and at the differentials that usually are not as “strong” as that we have in lfs.

Also in IRL a setup that loads only the front outside wheel would not work as good as it does in LFS because a real tire can not handle that mutch force and would loose traction easily under power…
In lfs as long as you increase the vertical load at a tire it just gives you more grip… that’s the problem and it is not a bug, it just shows that the physics model isn’t complete yet…

After all realistic setups work after the clutch pack preload addition, you just have to keep a realistic locking percentage at the LSD…

This setup I attached, is not made for any track, it is just an example.