The online racing simulator
LFS tyre model?
(66 posts, started )
#26 - troy
I don't agree on the "more grip on old tyres" statement though, to me it feels like the tyre, when it's getting thin, is running on higher internal pressure thus you get more speed on the straights which in turn makes you go faster over a lap.
So factors which may reduce the speed
1) Reduced circumference.
2) Possibly more deformation due to tire-wall thinning.
3) Overheated tires, reduced grip levels etc.

Factors which may increase speed
1) Lesser mass and moment of inertia of the worn out inertia of the wheel.
2) Probably more grip especially in road tires because, a worn out tire may approximate to slick and hence more contact area, as PMD reckoned
3) As someone above said higher internal pressure, as Troy reckoned

So it depends who wins the race, the factors which increase the speed? or the factors which decrease the speed?
troy: Old tyres have a lot more grip during turns too, it's not only a straight line speed advantage. It's overall "grippier".

rageshgr: Even slick tyres only get better and better with usage...
Quote from Meanie :

rageshgr: Even slick tyres only get better and better with usage...

Ya ya, what I meant is the effect may be more pronounced in road tyres, because, the wear will remove the ridges/groves and hence they may make road tyres flat like slicks, more surface contact area, more fritction, hence more grip.
New tires have some more grip but if you take a little slide you will gain much more heat and also you will skid much more. The overall car control is on the other level than just new tires.You can even see the brake point difference.
For some reason cars are a little bit faster with old tires but this has nothing to do with this thread as he was measuring car speed at specific RPM.

Today I was driving XRG and after 15 laps I should have changed brake point by 2 meters than new tire at good temperatures. As you said that grooves went off and the difference was really big and hard to learn new points. But also it was harder to reach the needed rear slip without skidding away too much with an xrg.
Quote :Reply from Scawen :
Your test seems to be correct, the change in circumference of a worn tyre is not modelled in LFS's current tyres. In the no slip condition (not accelerating) the contact patch moves along the road at simply the wheel rotation rate multiplied by the original circumference of the tyre. That means, it treats the original actual circumference as the rolling circumference, regardless of load or wear. In reality, the rolling circumference of a loaded tyre is slightly smaller than the unloaded circumference and that would change with wear as you say. However, the wear does affect the ride height of the tyre and you can see that by watching the force arrows of a slow rolling tyre with a flat spot.

Thanks Scawen for reply, and Victor for help (Vic there is something new in your inbox )
And Happy New Year to all
Quote from DANIEL-CRO :Thanks Scawen for reply, and Victor for help (Vic there is something new in your inbox )
And Happy New Year to all

You medal for the note. Well done and by the way happy New Year.
Based on the response from Scawen's in the new physics, this will be fixed. Thirst try new physics.

Scavier well done!!
other things that would be nice to implement, is expansion by temperature, because as we all know, gas expands with higher temperatures...


and, expansion by "rolling", my english is a little bad, so i can't explain it with words, so I'll explain with images and videos:



http://www.youtube.com/watch?v=1X7SnfpaugU
Expansion by temperature : Should be already there.

Expansion by rolling : As long as the tyre rubber has weight/mass, this will happen. Should be already there.

By the way, cool video.
I don't think those two effects are implementet. If they are, the effect is really minute, atleast for me to notice.
expansion by rolling, interesting thing never thought about that
my assumption is that forces caused by vechile weight are much higher than that, not sure though
Quote from DANIEL-CRO :expansion by rolling, interesting thing never thought about that
my assumption is that forces caused by vechile weight are much higher than that, not sure though

Search for some Top Fuel drag slow motion videos. Their super-soft tyres expend very aggressively.

On normal race cars people usually don't notice that at all.

i have never thought that tyres could get warmer like 40° at a single corner
Quite stunning temperature variation,but it's just surface temperature,seems like LFS shows temperature deeper in thread,where aren't such variation. Just guessing though...
I was surprised by the cooling rate
Quote from Eclipsed :Quite stunning temperature variation,but it's just surface temperature,seems like LFS shows temperature deeper in thread,where aren't such variation. Just guessing though...

Hold Ctrl + Shift with open F9 menu and you'll see the surface temperature...

You also see that tyre heating in LfS is clearly broken, as the core temp is trailing the surface temps only by a couple degrees...
the question of hpyerrealism
Hello!

I very much like this thread!

When I studied painting at the university some 15 years ago, I learned of a painting style called "hyperrealism".

Other then (foto-)realistic painting EVERY part of a picture would be completely realistic. Meaning: Objects in the foreground AND objects in the background would be painted as absolutely detailed as possible.

In (foto-)realistic painting only objects in the foreground are painted in exact detail, whereas things in the background are blurry, because the imagined "lense" can only focus on either fore- or background.

What am I saying here? --> the accurate simulation/narration of the "entire"
physics of 4 wheels might integrate a lot of thought, aspect and parameter, it will not, however, involve every Atom, Quantum, or matter of chance!

In the "pixelation" of all aspects of a simulation soon the whole thing becomes a question of computing power and speed, and when I think of LFS I must say, that one of it´s greatest qualities is that it runs on modest cpu&graphic power.

Inventing tyrephysics that are top-accurate for (let´s say) professional racing simulation in the real industry AND at the same time demanding everage computing power seems quiet contradictory.

What is the goal for future LFS - developments?

I like good pictures, I dont need hyperrealism, and it, as arthistory shows, has rather less, than more joyfull aspects.

FINAL QEUSTION: What are the minimum LFS S3 System Requirements? Maybe I should start saving money now!

Dandy
Quote from bbman :Hold Ctrl + Shift with open F9 menu and you'll see the surface temperature...

You also see that tyre heating in LfS is clearly broken, as the core temp is trailing the surface temps only by a couple degrees...

Wow,didn't knew that,thanks! Learned something new today!
That video shows how its done in rF2. In rF2, that happens :-P
RF2's diagram shows surface temp, or at least VERY close to the surface. As said if you hold CTRLSHIFT in LFS it shows output much like RF2.
Quote from bbman :Hold Ctrl + Shift with open F9 menu and you'll see the surface temperature...

You also see that tyre heating in LfS is clearly broken, as the core temp is trailing the surface temps only by a couple degrees...

Not only that... but at braking (as you can see in that vid too), tyre temp doesn't rise at all - it's only at cornering (with ctrl+shift).

Overall, this is my main issue with LFS tyre phicis - tyre heating/cooling and tyre grip related to temp (especially 'overheating').
Quote from bbman :Hold Ctrl + Shift with open F9 menu and you'll see the surface temperature...


Thanks for the info
Okay it is a bit off if you are looking at surface you clearly cant achieve that heating rate. But you cant think so much about cooling because the environment temperature is like 10 C here.

LFS tyre model?
(66 posts, started )
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