Hi,

Been playing around trying to make a set for the FXO at Aston GP, and I am having an issue with the tyres / camber.

The problem is as follows, no matter how much camber I put on the wheels (up to a point obviously), the outside third of the outside wheel on any given corner is having a more force than it should, I would ideally like the force to be as flat as possible throughout the turn, this wasnt so much of a problem with the previous patch.

I think that the issue might lie with the tyres, it seems as though the sidewall is deforming far to much, I know I have said it before, but I truely think that the sidewalls are far too weak, this leads, on road tyres anyway, to having trouble setting camber for even tyre wear, and to some degree pressures, as the tyres are getting warm on the inner and outer thirds, but sometimes cool in the middle (which generally means low pressure), it seems that no amount of camber adjustment or tyre pressure setting can give good results, it just seems as though the sidewalls have no strengh at all and just "blob" deform.

The following pictures are of an FXO, using the default RACE_S set, I thoughts?.

Dan,

I find the tyres much easier to make a set for, myself. it doesn't look as 'balanced' when you have the side sections heavily loaded, but it still grips fine and makes for more balanced tyre wear / heat. Does seem a little over the top, but this was discussed before...

Yeah, I know it was discussed before, and I am not just talking about the "look" of the tyres, I am talking about the effect that the sidewall has on setting up the camber and tyre pressures, it just seems that the sidewall is too easy to "push over" and causes the problems I am having with odd tyre temps/wear

Dan,

I know what you mean here danowat, I've thought about this myself.

Whenever I put HIGH camber for my wheels, it always seems to have the same affect of sidewall deformation. In a sense, if I had like -4 camber on the front, the inside should be touching mostly I would think. However it is always the outside edge that gets pulled underneath.... Isn't camber one way to get rid of that too?? That is one principle of camber as far as I know, and LFS is doing it quite wierd I think.

Not only that, but I have noticed that some people are setting up their cars with some incredibly high amounts of camber. Take the XR GT for example. People are using -3 on the front and upwards or near -4 on the rear. This is A LOT of camber... yet that makes the car faster in cornering apparently. I really do think this is incorrect, since there is usually a limit for how far some cambers are put on cars in racing. Too little of camber won't perform well, and too much camber won't perform well. Except LFS seems to be different... somehow.

But seriously, -4 cambers being functional, and fast? Ehem...

I think the excessive camber is coming from the fact that the tyre sidewall is deforming so much that you need serious amounts of camber to get the tyres to run "flat" throughout a corner.

This causes a multitude of problems for me, I just think that the sidewall has little or no strength at all, the elastic deformation of the sidewall almost makes it seem as it is not reinforced at all and it is just rubber.

Dan,

Well, 4° isn't all that much when you think about it, or is it? Compared to what was good in pre S times it's extreme, yes, but who says the camber settings were *realistic* back then?

I guess we'd really need a mechanic here who could answer these questions with actual values used in racing, everything else will just be speculation of how we think it should(n't) be.

Yes, very true, we need someone who knows more about tyres/camber than I do, at the moment I am basing my conclusions on the default RACE_S set, which I am assuming has "realistic" camber and tyre pressure settings, depending on weather this is indeed the case would make a big difference in whats right/realistic and what isn't.

I am all ears.

EDIT : Interesting piece here I found about Toyo tyres

" Camber Settings
Toyo motor sport radials will provide optimum cornering grip with camber settings between negative 3 and 6 degrees on steer axles. Where adjustment is possible, negative camber on drive axles will also improve cornering grip. Optimum camber angles will provide optimum cornering grip, and therefore will be an important contributing factor for improving lap times.

NOTE: On some vehicles a lack of negative camber can over-heat the outside tread shoulder causing grip levels to drop-off suddenly and in some cases cause blistering of the outside tread shoulder. Large heavy, front engine cars are most susceptible to this type of tyre damage.
CAMBER SETTINGS & INFLATION PRESSURES

Where camber adjustment is limited or class rules limit the amount of negative camber allowed, increasing cold inflation pressures is necessary to prevent the outside tread shoulder overheating. This also applies to vehicles that are used on the street as well as the track, where the camber settings are a compromise for this dual purpose. Where this is the case, adding 3 - 6psi to recommended cold and hot inflation pressures usually prevents the outside tread shoulder over-heating. "

Dan,

The only race cars I know of that have some wild cambers for the wheels is the V8 Supercars. But even then, the cambers are not all that wild on the rear.

http://www.lightmoves.com/news/v8supercar3.jpg

http://www.macktrucks.com.au/C ... ge/News/V8%20Supercar.jpg
http://www.ford-team-mittellan ... car%20Jason%20Bright2.jpg

But even for a slick, it doesn't deform as much as LFS I think

@danowat: very interesting read. Seems not too different from the current situation we have in LFS

@Tweaker: yup, those cambers are really extreme... look something like 8° to me.

In LFS it depends a lot on the air pressure in the tyres, and because lower = faster, you need extreme camper to get the inside of the tyre in the ground

Trade offs here too. Too much neg camber on the front of a front wheel drive will result in less traction as you unload the suspension out of a corner or from a standing start. Similarly, too much neg leads to poor braking grip.

But I think there is no hard and fast rule. Different suspension geometry reacts differently to loads which result in camber angles in bump and droop varying. So I don't see how anyone could say that static camber should be between x and Y because it varies from car to car, setup to setup. Other factors that would influence your choice of camber include the level of grip, corner radius, downforce, tyre choice etc.

Best approach is to test and feel I reckon.

There's something not quite right with the games tyre model imo. We took the BF1 around BL1 last night and no matter the camber/pressure settings the inside of the tyre was burning after a couple of laps - the tyre itself remained cold.

This shouldn't, and certainly doesn't happen to tyres designed for formula-one cars at least.

We finally managed to find a solution, fiddling with the tyre pressures and using high-compound tires. I still think there is something not quite right in the game concerning this..

Quote from Gentlefoot :

Best approach is to test and feel I reckon.

There in lies my problem, I am testing and feeling, get it set up reasonably well, then I watch a reply with the F9 tyre display on, and its clear that on high load corners the outside third of the tyre is taking a huge bashing because the sidewall is collapsing, and to cure it the camber needs increasing to values were the inside of the tyre takes a bashing.

I understand that setting up a car is a balancing act, but I can't help but feel that the tyre sidewalls give up the ghost far to easily.

Dan,

What tyre pressures you using Dan? I have noticed that best tyre pressures in LFS are way too low. This would definately contribute to poor sidewall strength.

32 PSI on the fronts, which should be enough IMO.

Dan,

You're dead right there, probably even a bit higher than IRL for short runs anyway.

Is the problem occuring on all corners at Aston?

I always tend to set up for the two or three most important corners on a circuit.

Oh and I'm also slower than you so what do I know!

Its more of a general thing, rather than a specific corner or track, I first noticed it while setting up for KY Nat a few weeks ago, then I posted about the tyres deforming to much, now I believe its just the sidewalls that are giving the problem, I wonder if they have anymore strength in the sim then the rest of the tyre has, they just seem to stretch and pull all over the place.

Dan,

I wonder if other factors are contributing. If you're setup is generating good mechanical grip then this will put more force on the tyre sidewalls.

But it sounds like you have hit a problem with the tyres. Maybe they are modelled on Korean remoulds.

we had the discussion before in your thread about the tyres deforming too much ... most there agreed with me that it seems like the sidewalls strech instead of just bending ... which is wrong

When comparing the static camber of the roadgoing cars you also have to keep in mind the camber curves of the specific suspension layout. A car with a twist beam/trailing arms setup like the XFG will always need lots of static camber. Same goes for MacPherson struts on the XRG.

I find I need to run maximum negative camber (both front and rear) on the UF1, even when the set is as stiff as low as I can get it. But I suppose it still suffers from a lack or ARBs.

isn't the "problem" that in lfs you don't see many really stiff sets... I think that IRL the sets are pretty stiff...
or i didn't catch the real meaning of this thread, skimmed through only, cause i got a lot of work on my hands now (race weekend preparation and testing)

Quote from Shotglass :

we had the discussion before in your thread about the tyres deforming too much ... most there agreed with me that it seems like the sidewalls strech instead of just bending ... which is wrong

Maybe there is a difference between the visible tyredeformation and the deformation actually calculatet by the engine. To display real bend you need a lot of polygons, and I guess the tyre has in radial direction only two or three intersections. Could be that the bending looks like strecht, caused by lack of polygons

I am going beyond the visual representation of the tyre, and using the force bars and tyre temps to try and figure out what is happening to the tyre on high load corners.

My main concern is the amount of camber I need to run to get a decent "flat" tyre through a corner, and how quickly that amount of camber ruins the tyres.

Dan,

Quote from Hahni :

Maybe there is a difference between the visible tyredeformation and the deformation actually calculatet by the engine. To display real bend you need a lot of polygons, and I guess the tyre has in radial direction only two or three intersections. Could be that the bending looks like strecht, caused by lack of polygons

doubtful because of serveral reasons
a) most improtantly even if that is the case the sidewalls still strech a lot ... too much if you ask me ... even considering they might be bent normally and straighten out when they strech
b) it wouldnt fit into the general style of lfs being a wysiwyg or rather a wygiwys (what you get is what you see) game with a very close realtion between graphics and physcis
c) the performenace impact of having more sampling spots on the sidewall would be a lot higher than the impact of drawing the appropriate polygons