The online racing simulator
The elephant in the living room (Tire Physics)
Basically, I got so tired of the hot tire physics today, that I made a short demonstration of the issue. I'll let the video do the speaking for me.

http://www.youtube.com/watch?v=eFP0Eylmd1I&fmt=22

I rarely see anyone on this forum point this problem out, and I consider it to be a big deal enough (a bloody huge one, in fact) that it deserves more attention to itself. I just can not grasp the thought, that scavier sleep their nights in peace while LFS tires are in this sad state of unrealism.

The tires weren't always this bad either, I watched one of my earlier videos from the early 2005 S2 demo times, and it was possible to do laps and laps worth of wheelspinning until the tires got so hot that they started to lose massive amounts of grip. That was a lot closer to real life than how the hot tires now react in the current version of LFS.

The point of this post? Well, it would be nice to see this issue noted and fixed. (Lessee how many posts until the first "well don't drift/this isn't a drift sim" post comes up)
#2 - senn
maybe i've missed the point, but if your tyres are too hot, they won't grip very well, which in your case is the "Hot" tyres. So i fail to see the issue?
Did you try the "hot" tests with the tyres surface green (optimal grip)?
The point, plain and simple, is that the hot tires have way too little grip than they would in real life. Totally cold tires and optimal temp tires have very little difference that matters to this test. Doing the "cold" tests with optimal temp tires would only enforce what I'm trying to prove here, since they grip more than totally blue/cold tires.
#4 - senn
can you offer any proof?
btw, Matrixi, try with realy cold tires, stay on track about 30 min. ,and then drive, like on ice...
What you've proven is that hot tyres in LFS have less grip than cold tyres in LFS, but not that it's not realistic.
Next time, do a comparision with real-life cars in real-life conditions so that we can see what is realistic and what isn't.
Proof? Unfortunately I don't have a car in real life capable of doing these kind of tests, but if you consider what you have seen happen on those LFS hot tires being any way realistic, I'd strongly recommend a reality check.

This is exactly what I expected from this forum though, anything that happens in LFS is automatically realistic. No questions asked, ever.
Were did you got that rev limiter?
#9 - senn
i didn't auto flame you, i'm just trying to work out where you have gotten your info from? Was it an article or video? Can you give us something to compare this to?
Nice video. I have been thinking the same thing. LFS is said to be realitic, but I wouldn't say so. These tire grip levels are VERY unrealistic. Yes, basically that is soap. The worst of 'em all is RA, but all other non-GTR cars too, cars are driving on ice, it's easy to powerslide and so on. LFS should have better tyre physics.
I hope Devs will fix it
#12 - senn
fix what?
Quote from bmwracer67 :Nice video. I have been thinking the same thing. LFS is said to be realitic, but I wouldn't say so. These tire grip levels are VERY unrealistic. Yes, basically that is soap. The worst of 'em all is RA, but all other non-GTR cars too, cars are driving on ice, it's easy to powerslide and so on. LFS should have better tyre physics.

bmwracer67, can you elaborate on how it must be? Same question to Matrixi.
PS. Actually I'm just interesting
#14 - senn
Quote from Matrixi :Proof? Unfortunately I don't have a car in real life capable of doing these kind of tests, but if you consider what you have seen happen on those LFS hot tires being any way realistic, I'd strongly recommend a reality check.

This is exactly what I expected from this forum though, anything that happens in LFS is automatically realistic. No questions asked, ever.

Cold tyres have low grip, tyres grip better as they get warmer, until a point, and then they lose grip. Thats a fact. (and something i've experienced first hand in my own car)
Now, if you want to be taken seriously, and especially after saying what you did above, you can answer this question - On what information do you base your claim that LFS has "unrealistic" tyre modelling?

Thanks.
Quote from senn :On what information do you base your claim that LFS has "unrealistic" tyre modelling?

Purely from the experience I have from drifting my old 200SX. Also, I wouldn't really want to advertise iRacing so much here, but the tires in that sim do not turn in to soap after they get hot and their pressure rises. They simply lose a LITTLE bit of grip, not the majority of it. Just an observation.
#16 - senn
thanks for clarifying your point much easier to understand now.
#17 - Byku
What Devs should work about is tyre wear, most road cars will start to lose tyre grip after around 4-5 laps around average track. See Best Motoring International for proof. In LFS when You have optimal tyre temp, You can go on them for really long time. At least i think so . Btw. Yeah, whet tires are REALLY hot they seem to have REALLY low grip. Btw2. Scawen mentioned that this year he will work on physics . Btw3. Ohh... i love how the suspension and weight transfer works in LFS *_*, it's soo lovely.
Nice video, I sit on the wall regarding the physics debate.
May I say, sir, that you have an excellent taste in music!
Quote from Matrixi :Purely from the experience I have from drifting my old 200SX. Also, I wouldn't really want to advertise iRacing so much here, but the tires in that sim do not turn in to soap after they get hot and their pressure rises. They simply lose a LITTLE bit of grip, not the majority of it. Just an observation.

Were you using road tyres or racing tyres in your 200SX? Do you know exactly how hot they were getting? (ie over 150 degrees C like in your hot tests in the video)

Tyre physics are notoriously difficult to model - as proven by the many improvements in LFS's model, yet it's still widely considered to need further improvement. iRacing is just another simulator - do we know if they had better tyre data than what Scawen has been given + researched?

There are a lot of variables and unknowns at play here as well as a lack of real world comparison with similar tyre compounds and treads with accurate temperature and grip data.

Do LFS's tyre physics need improving? Almost certainly
Do we really know how accurate they actually are? Not really
everything is correct
Tyres are and always will be a big issue in sims. They are probably the hardest of things to model correctly. Diffs, suspension etc are easy compared. Sure, LFS has issues on this area, a lot.
But what can you do? If you just simply increase the grip of hot tyres what will happen then? Wouldn't it it also be unrealistic if hot tyres would grip as almost well as optimal tyres? Solving the tyre problem is not easy like that. You need to rethink the whole issue not just some small part of it.

Again I am not saying that LFS tyres are perfect now, far from it. They are actually very simplistic now, only heat and the thickness of the rubber is taken in to account (afaik). In real life tyres have more attributes than that.

In conclusion tyres are a big issue. But do you think they should be the only issue? There are plenty of other things the devs have to also take care of. There is more to this than "this is wrong, now fix it".
There is a difference beetween weared tyres and over heated tyres. But I see your point though.
Quote from Degats :Tyre physics are notoriously difficult to model - as proven by the many improvements in LFS's model, yet it's still widely considered to need further improvement. iRacing is just another simulator - do we know if they had better tyre data than what Scawen has been given + researched?

There are a lot of variables and unknowns at play here as well as a lack of real world comparison with similar tyre compounds and treads with accurate temperature and grip data.

Do LFS's tyre physics need improving? Almost certainly
Do we really know how accurate they actually are? Not really

Agreed. Personally I have no clue how much you'd have to abuse real-life tires in order to make them as hot as in the video. Maybe it's not even possible for all I know.. could be they just turn to mash long before.

But why does it really matter all that much? Really, if you've got your tyres glowing red hot like in your demonstration, you should work on your driving style.

My main gripe with the tyre model in LFS remains the lenient slip angles and smooth transitions from grip <--> slide. This is something that affects us in all races. But that's another discussion.

The elephant in the living room (Tire Physics)
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