Hello.

LFS's tyre physics assume that the tyre behaves as 16*3 blocks of rubber (or whatever the number was, not important here) that go from the top of the tyre-surface to the end of the usable tread.
This is a proper assumption for typical tyre operation. The tyre temperature and wear behaves properly when driving normally.
When locking the tyre this doesn't work well though. When a real tyre locks a very thin top layer of the tread heats excessively and melts away within a second, creating a flat spot. In LFS the complete tread-section has to heat until it starts melting. That's why it is so difficult to flat-spot an LFS tyre.
Since increasing the number of tyre sections isn't sensful (the double amount of sections would still suffer from the problem to a certain degree) LFS should make assumptions about the temperatures in the topmost layer of the tread which could then be used to model proper wear.

Vain

Have you ever pressed Ctrl+Shift when the F9 display is open? There's your surface temp

Thanks for sharing that info. Much appreciated.

Then I wonder why flatspotting doesn't work properly.
I know that by locking the tyres up for 2-3 seconds semi-slicks used in club racing can easily be flatspotted to a degree that they need to be replaced or they'd destroy the suspension within an hour of driving.
Either something about the surface temperatures and wear is wrong or the suspension damage model isn't capable of reproducing the proper effects. I wonder what kind of damage accumulation calculation Scawen uses...

Vain

My bet is on the suspension damage model simply not being affected by small violent bumps/vibration.
That, and I think the flatspot modelling is probably a bit lacking too. Here is a crude animation of what I think happens in LFS - you simply have an almost resistance-less up/down bump on the flatspot, instead of the real flat surface, which would also cause a short spike in rolling resistance.

Is there even "a bump", or any change in tire diameter at the place of flatspot in LFS? In other words, I don't think the radius of the tires changes with wear, in LFS. Can't prove it though...

And to the whole tire temperature model, the tires seem to lose too much grip on higher temperatures, in all cars/tires.
http://www.lfsforum.net/showthread.php?p=166576#post166576 and onwards.

And there might be something not right (or not simulated at all) in the tires regarding the heat model between the tire blocks? And on some cases it is quite wrong. Like the tire blocks get very heated if you drive 1km/h with handbrake on, not an issue though, or can't see it as one...

The suspension model, the damage part essentially doesn't cover the vibrations caused by tyre or coming from tire. And to be honest, it is really rare that the suspension breaks in any way due to vibrations being the main cause

Quote from Hyperactive :

Is there even "a bump", or any change in tire diameter at the place of flatspot in LFS? In other words, I don't think the radius of the tires changes with wear, in LFS. Can't prove it though...

It's odd. The effect should be quite noticeable, say 3 or 4mph less at high speeds for a given rpm and gear ratio (between fresh tyres and about to fail from wear). Of course with the latest style speedos that don't report true ground speed anymore, there's no way to tell without running outsim/outguage to get the speed and comparing.

I haven't noticed it myself but it is possible to feel a vibration effect with a heavily flatspotted tyre, although it only seem to be at certain speeds when cornering. So that would point to it being simulated.

I once experimented this with fz5 locking the fronts and driving a straight from end to end multiple times, only after the tires were near a puncture (don't remember whether it would've been from heat or wear) I got a very small vibration in ffb. Something is obviously lacking in this department, tyre simulation, suspension simulation or ffb simulation.

The flatspots are really only noticable at lower speeds through the FFB; presumably because by the time LFS sends the force to the wheel, and the wheel does something about it, it's no longer relevant. At medium to high speeds I only note the odd transient force in my G25 (talking about flatspots), but at low speeds (quite low) I can feel every rotation for sure. It varies from car to car and setup to setup, just like the kerbs - which I feel fine most of the time, but not all. It depends how much weight is on the affected tire(s), and how fast you're travelling.

But I agree with Vain, some tweaking is necessary to get it more true to life for sure.

i think there is flat spotting whit slick tires...

There is flatspotting with all kinds of tyres. Just the consequences of a flatspot are almost non-existent. And yes, the tyre circumference changes with wear (and thus also on flatspots).

It just feels that the tire jumps over the flatspot in higher speeds. Basically as in the animation Android (with the cute fluffy kitty avatar) posted, except the drop only happens in very slow speeds. The tires definitely lock up easily if you have a small flatspot, but is it because the grip loss of the heated surface or the actual flatspot? And if it jumps over the flat, could it be because LFS can't calculate the tire going round and round fast enough and react to it?

But then, if we had more realistic flatspots, how would they be implemented. Should the view and wheel just vibrate and shake like hell?

a flatspot you should only feel on the slicks. streettires doesnt wear that heavily.

Besides that the tirediameter decreases with wear, that's pretty nice modelled, the cars get lower with racetime (GTRs best example to feel). Even in OpenWheelers IRL you dont really feel flatspots, only when they really get huge (Kimi anyone?). So in the possibilities of LFS engine, it's imho very well done atm.

Well I recall F1 drivers saying flatspots making the car shaky and vibrate so it's hard to see forward, but then, I guess they do wear off in time (happens in LFS if you are carefull).

Of course, your new friend Nick should know a ton more about this Vykos, have you already asked him about this?

Quote from Vykos69 :

a flatspot you should only feel on the slicks. streettires doesnt wear that heavily.

R-compounds do..(falken azenis for that matter..super-road tires?)

you can both feel flatspots in the ffb and see the car shaking
personally i dont think a tiny diameter change will have much of an effect on angular force on the wheel so my take on it is flatspot ffb is a hell of a lot closer to reality in lfs than in nkp ... or in other words youd need an incredibly quick 301 to get the flatspot effect and not a ffb wheel

Good points Shotglass!

FFB chairs FTW.

Quote from Ball Bearing Turbo :

FFB chairs FTW.

nice idea ... i can already see tiny and becky flatspotting their tyres all the time

:ices_rofl



:monkey:

Where has your mind been lately?