" should note that the LFS road tyres are softer than the sort of tyres most of us use on our cars. Just look at the grip they provide. Road supers give well over 1g in a corner, something most "shopping car" tyres will never give.

So don't think of Road supers and normals as direct link to RL road tyres"

High performance tyres on high performance road cars do give very good grip and handling. subary impreza' s and mitsibishi lancer evo' s are very good examples.

Also overheated tyres irl grip better then in lfs. Also shown in the drift movie. Also note in the a "get away from stockholm movie" a tuned nsx(500+hp i guess) was doing a rather very long burn-out. Yet she could still drive away with some dificulty because she was nearly flooring it but accalaration was still good dispite rear tyres still smoking from the burnout. After less then a minute grip was back to normal.
Very unlike how tyres in lfs behave...
It shouldnt be too difficult to have a fix to make grip loss severe when tyres are overheated or below optimum tempature.

Also very odd.. people keep on defending flaws in lfs and totally denying, refusing to believe real world examples. Why is that?

Lfs is very good, but not perfect, is there something wrong about not being perfect?

LFS is far from being "perfect" and sure still has a lot of flaws, I don't think anybody's denying that. However, comparing to real life examples or -anecdotes always has the very error-prone factor called "human" in the middle, who was responsible for silly things like huge drop-offs on long/lat grip curves to begin with, simply because the brain falsified the "felt" data.

I think that's why the LFS folks have become very wary of random people giving their realism advices based solely on feeling, rather than for example taking properly measured telemetry data.

Also some are greatly underestimating the complexity of the tyre physics alone, thinking that changes can be easily made without breaking a lot of other things.

Quote from Bluebird B B :

Also very odd.. people keep on defending flaws in lfs and totally denying, refusing to believe real world examples. Why is that?

Lfs is very good, but not perfect, is there something wrong about not being perfect?

Was just pointing out when "most" people think road tyre what they think of is nothing like what LFS calls a road tyre. You are right they should be thought of more like tyres found on the Wrx or Evo for their softness etc.

We know that LFS is not perfect and Scawen has stated that the tyres need more work in a current thread (Don't have the time to re-find at the mo). But for their current state are a good approximation.

Drifting, burnouts and the like probably show this up more but in most race conditions they are good. So for what LFS "aims" at for the time being they are not too far out.

From Scawen himself:

Quote :

And just to add : the tyre heating and temperature vs grip characteristics on the tyres is not finalised. Those characteristics are too rough an approximation at the moment.

http://www.lfsforum.net/showthread.php?p=674302#post674302

And:

Quote :

The road supers are supposed to be actual road legal tyres, like track day tyres, not full racing tyres.

The rallycross tyres are real racing tyres, so they do have some good grip on the road. Though they overheat too quickly to be used in most situations on most of the road cars.

http://www.lfsforum.net/showthread.php?p=674299#post674299

In order to prepare myself to longer races I did 60 laps race with AI today (BL1 track). At the beginning of the race I did some slides and was kicked by AI driver off the track. So I've got my R2 tyres cooked to 115 degrees. After 2-3 laps without slides temperature dropped to green range. And most of the race I've been able to keep them below 90 degrees. I've been using my slightly modified short race set, but camber wasn't changed.

Look at my tyres' temps at lap #32 just before pitstop.

By the way, I've forced AI to use my set but they were wearing R1 tyres when I was on R2

Im not getting why you would want your tyres to cool off faster? In r/l club racing, tyre warmers are used to maintain heat between races. They do this because of two things really; heat cycles and getting the tyres to race temps faster on the track.

Yes there is that chance that if you over cook them and they turn to mush that yopu do want to cool them off a bit, but that usually only happens if your driving like a mad man. Any smooth driver wont have that issue: drifters need not apply.

In the UK most series do not allow tyre warmers. They are certainly not within the budget of the vast majority of club racers. Besides, a tyre warmer will NOT get or keep a tyre at operating temperatures, and so a heat cycle is still considered as occuring even if you put them on straight after a run, although you can reduce the rate of cooling by doing so.

I am with the OP for one reason. If you drive any open wheeled car's (more directing towards the LX series) The tires are verry hard to get from green doing sensible racing.

No matter what their will be a lot of air speed going under the car.. Any amount of air rushing threw a tread-ed tire will cool it down A LOT. If you look at a lot of new hybrid cars the cover up the whole rear wheel well area because there is that much air being pulled into that area.

Also I think there should be a better grip limit on red tire heat value because, it's not like you have no tread left.

Lack of grip is not associated with lack of tread but because the tire is too hot and the rubber doesn't act optimally there. DOn't exactly know what happens to road tires, but racing tires start to blister and actually melt. I guess it's the same here. Less tread (when you just use it all up on the whole tire, uniformly) will even give you more grip - more surface area...

And learn to write in english dammit, your official language is not engrish.

Quote from Primoz :

Less tread (when you just use it all up on the whole tire, uniformly) will even give you more grip - more surface area...

And learn to write in english dammit, your official language is not engrish.

Pressure = Force/Area

More surface area does not mean more grip. A larger contact area between two surfaces would create more grip, but the pressure between the surfaces is reduced because the force hasn't changed(note equation above for this). The increase in friction generating area is exactly offset by the reduction in pressure. The resulting frictional forces(grip) depend only on the coefficient of friction of the materials and the force holding them together. Now if you increase the force(vehicle weight) as you increased the area to keep the pressure constant, then the increased area would increase the grip between the two surfaces.

Sorry, but my mechanical engineering senior project included machine design that took advantage of a rubber gripper, so I had to clear up that misconception.

Quote from NetDemon01 :

Pressure = Force/Area

That equation is only true for hard surfaces. Rubber is far from hard. The frictional force a rubber, steel-reinforced tyre creates are very complex indeed.

Edit: I should clarify, pressure at the contact patch can be defined like that, but the longitudinal and lateral forces a tyre can produce do not scale linearly with vertical force. For example, increasing tyre width by 20% will increase contact area by 20% (assuming it does not affect the vertical stiffness of the tyre), but the load stays the same, so pressure indeed reduces. Pressure reduces the coefficient of friction though, so the tyre now has more grip.

Quote from Lautsprecher[NOR] :

A nasty scissor should also come out of one of the DVD-ROMs and cut his balls off!

:ices_rofl:ices_rofl:ices_rofl:ices_rofl:ices_rofl:ices_rofl

Quote from Bob Smith :

Pressure reduces the coefficient of friction though, so the tyre now has more grip.

I'll agree that the coefficient of friction can depend on pressures and temperatures and other aspects of a system. Considering the tire "weight" force, and the equal and opposite normal force, plus the friction force that allows the tire to roll across a surface; a reduced coefficient of friction(along with the unchanged weight/normal force) means the friction force is also reduced.

I don't see how you're figuring a tire has more grip with a smaller coefficient of friction.

If Friction = Force / Area, then non downforce cars will never be able to generate more than 1g acceleration. Top Fuel cars prove this VERY wrong.

Smooth Body equations at school have little bearing in the malleable and imperfect real world.

Who ever said Friction = force times area?

Quote from NetDemon01 :

I don't see how you're figuring a tire has more grip with a smaller coefficient of friction.

Read what I posted more carefully (as it wasn't worded brilliantly). I said [increasing] pressure reduces friction, so having a wider tyre gives less pressure and thus more friction.

Quote from NetDemon01 :

Who ever said Friction = force times area?

Likely a typo.

Hmm...you were talking about decreasing pressure so with this statement:

Quote :

Pressure reduces the coefficient of friction though, so the tyre now has more grip.

I figured you meant to say "[decreasing]Pressure reduces the coefficient of friction though...."

I guess we are really on different paths. And it would be easiest to assume a certain state of system. How much pressure are we talking? For low pressures, friction and the pressure are directly related, meaning more friction with more pressure, less friction with less pressure.
So to sum it all up as my understanding, our increase in area causes a decrease in pressure. A decrease in pressure causes a decrease in friction.

But I have misread what you wrote ? You really did mean "[increase]Pressure reduces the coefficient of friction" ? I would need this indirect relationship explained. Basically, how much pressure are you talking about?

Quote from Primoz :

Lack of grip is not associated with lack of tread but because the tire is too hot and the rubber doesn't act optimally there. DOn't exactly know what happens to road tires, but racing tires start to blister and actually melt. I guess it's the same here. Less tread (when you just use it all up on the whole tire, uniformly) will even give you more grip - more surface area...

And learn to write in english dammit, your official language is not engrish.

Yes correct, but 10 degrees of higher temp will not rip apart your tyres. Offcourse grip will be a bit less but only a tiny bit. Overheat the tyre over 25 degrees, yes ok at such overheating soft racing tyres wil come apart.

High performance road-tyres perform very well in a very large range of tempatures, because they are designed to work in the rain with low tempatures, but alsof in very hot dry deserts.
The tyres on my own car have optimun grip from 15 degrees celcius all the way up to about 65 degrees. And also grip well all the way down to 1 degree celcius. Despite loaded to there max limit, because my car is rather heavy, i never managed to get the tyres over 55 degrees. EAlso when the wheels were totally wrong alligned with enormous amounts of toe-in front and rear(nearly full degree).

However, cheap "high" performance tyres do indeed act like the ones found in lfs. They get hot fast, stay hot, grip uh dont grip at all when cold or hot, wear out fast because the rubber is too soft. I once got such things with the car i bought, it was not a a performance car the engine had just 125hp, but even on that car the tyres were dangerously bad despite the manufacturer stated the tyres could handle max speeds of 240+ km/h.

So one could state, the tyres in lfs are simulating cheap high performance road tyres.

In lfs, its dead man racing with tyres at 10 degrees(if it would be possible) and you can burn your tyres within minutes with setups designed to keep the tempature down.

I just think tyres irl are more tolerant then in lfs. I think this is also true for the racing tyres.