The question is though, how do real race teams find out how much the inner/average tyre temperatures fluctuate? Most probably only measure the tyre temps at a pitstop, which is far too infrequent to get any data about fluctuation. The only other way I could think of would be thermal cameras, but these would only measure the surface temperature, which already fluctuates quite a lot in LFS. Or maybe sensors embedded in the rubber, but this is getting quite ridiculous in terms of cost/feasibility already.
The question is though, how do real race teams find out how much the inner/average tyre temperatures fluctuate? Most probably only measure the tyre temps at a pitstop, which is far too infrequent to get any data about fluctuation. The only other way I could think of would be thermal cameras, but these would only measure the surface temperature, which already fluctuates quite a lot in LFS. Or maybe sensors embedded in the rubber, but this is getting quite ridiculous in terms of cost/feasibility already.
Non-contact, infrared thermometers, mounted by or over the tyres are how the teams can measure this; three per tyre. I don't know how common it is, but I've heard about Le Mans teams using this kind of system.
The trouble with IR pyrometers is that they only measure surface temperature, which is actually a pretty meaningless number, and will vary with braking, acceleration and turning, and doesn't really change the friction of the tyres. Sticking a needle pyrometer some known and repeatable depth into the tyre surface is the only way to be accurate, which doesn't work well with turning tyres!!
Having said all that, I own an IR pyrometer (for measuring things other than tyres), and can't afford a needle type, so we measure our tyre temps using the IR method, in the pitlane after a hard lap. We don't bother measuring after a slow lap, e.g. after a race or practice session, because they are as meaningless as reading spark plugs after a few seconds of idling.
Having said all that, I own an IR pyrometer (for measuring things other than tyres), and can't afford a needle type, so we measure our tyre temps using the IR method, in the pitlane after a hard lap. We don't bother measuring after a slow lap, e.g. after a race or practice session, because they are as meaningless as reading spark plugs after a few seconds of idling.
I'll tell you how you can tell the temperature fluctuates, get in the car and drive, you can bloody feel it!
Do a few laps, say 5 or 6, on the nail. Then drive a sector at half throttle and get back on it, try not to be too embarassed at the first corner you reach, corner or two later will be back to normal.
Yes I raced bigger stuff than karts, did more than a few seasons too.
Do a few laps, say 5 or 6, on the nail. Then drive a sector at half throttle and get back on it, try not to be too embarassed at the first corner you reach, corner or two later will be back to normal.
Yes I raced bigger stuff than karts, did more than a few seasons too.
I've had not a lot infact nothing to do with racing, but I used to work in a Production Plant (many moons ago) that manufactured large cables. We used to use thermal imaging cameras (Infra red) for measuring the temperature of the extruded polyethylene, high and low density. I would imagine sticking a few of these little devils on the wheel arch, or even on the wheel itself would do the trick, well thats what I would do if I was given the task of monitoring tyre temperatures anyway 
Edit, should read the whole thread before posting, also if you know the heat transfer characteristics of the rubber, you could calculate the inner temperatures from the surface temperature at any given moment.
Edit, should read the whole thread before posting, also if you know the heat transfer characteristics of the rubber, you could calculate the inner temperatures from the surface temperature at any given moment.
Ah yeah, how could I forget the feel method :doh:. We all know how invaluable it was for providing realistic tyre grip curves.
Nah but seriously, "feel" is nice and it can definitely point to flaws in the current modelling, but feel alone is not a good source to generate actual data/formulas for. Maybe the temp modelling is fine, but the influence of surface temp on the grip is wrong. Or maybe the temperature - grip relationship itself is wrong. Who knows.
Nah but seriously, "feel" is nice and it can definitely point to flaws in the current modelling, but feel alone is not a good source to generate actual data/formulas for. Maybe the temp modelling is fine, but the influence of surface temp on the grip is wrong. Or maybe the temperature - grip relationship itself is wrong. Who knows.
In my experience LFS does have some short-term heatup, because after I have spun the car I find that the wheels have less grip in the next corner (often causing me to spin again
). The next corner, things are back to normal. This heatup is not visible in the F9 screen.Well, the surface temperature is visible if you hold Ctrl+Shift while in F9 mode.
Surely that would only work if you know the energy into the system (friction in this case, heating the rubber), the thickness, the temperature at the other side of the rubber, the internal and external air temperatures, figures for aero cooling (including 'wind chill' in turbulence) etc.
You could have a tyre that is 500°C on the surface, but only 30°C a couple of mm in, or 100°C on the surface and still 30°C depending on how it's been heated and what conditions are prevailing.
As far as I am aware all materials have thermal conductivity properties that can be determined and calculated.
Please don't make me get my books out I've got the day off work and I'm buggered if I'm doing any bleedin engineering on my day off. Well unless you want to pay me my going rate lol. I'm sure there will be some engineering graduates that would like to answer you in no more than 3000 words??
Anyway i'm going back to the post that talks about how many 5 year old kids you could take out at once
Please don't make me get my books out I've got the day off work and I'm buggered if I'm doing any bleedin engineering on my day off. Well unless you want to pay me my going rate lol. I'm sure there will be some engineering graduates that would like to answer you in no more than 3000 words??
Anyway i'm going back to the post that talks about how many 5 year old kids you could take out at once
Forgive me for being a dolt, but... if surface temperature is so meaningless, that means the only real data that is available is taken by a probe in the pitlane (inherently inaccurate too). And by extension, that means LFS' tyre model is a "best guestimate". So why not just use the "feel method" as there doesn't seem to be a more accurate method available?
Although I have to agree with you, how could those with doctorates in material science justify themselves and charge Bridgestone mega bucks
While I qualify for the engineering bit the dynamics of tyre temp remains a tremendous piece of work!
You have to take in account the cooling / heating at the contact point with the road surface, air and its turbulences around the tyre, dynamics inside the tyre rubber(I don't know the english term for rubber moving around inside the tyre, creates heat by shearing), pressure applied on the tyre...
I don't see the end of it, the mathematical model for this would be either too simplified to get good results or too complicated to be solved.
I think the approach of the dev team is good, build a (relatively) simple model and tweak it to get close to real life values when you stop the car and sensible looking temps during a race.
Now talking about rates: you should happily do it for free, for the sake of the challenge it offers
Good luck!
You have to take in account the cooling / heating at the contact point with the road surface, air and its turbulences around the tyre, dynamics inside the tyre rubber(I don't know the english term for rubber moving around inside the tyre, creates heat by shearing), pressure applied on the tyre...
I don't see the end of it, the mathematical model for this would be either too simplified to get good results or too complicated to be solved.
I think the approach of the dev team is good, build a (relatively) simple model and tweak it to get close to real life values when you stop the car and sensible looking temps during a race.
Now talking about rates: you should happily do it for free, for the sake of the challenge it offers
Good luck!Yes, they do. But how can you know anything other than the surface temperature (measured) if you don't know anything else. If the conditions were constant, so the rate of heat retention and dissipation remained the same you can sort of work it out, but on a tyre in continuously changing conditions you cannot work it out.
Do you agree the core temperature will vary with both surface temperature and rate of external cooling? In which case, bearing in mind we don't know the REAL rate of cooling in the turbulent air around a tyre (and some of it is on the ground anyway) then we don't know enough to solve the problem. And that's with one variable. Now add another 50...
As for not being able to measure tyre temps at all, don't forget some manufacturers now have quite advanced tyre testing rigs, which will allow real time internal feedback from a tyre (without aero influences)... It is possible to get some data, but it's rarely in the public domain.
As for feel, you can (up to a point) if you can actually feel anything. Whilst I can feel sidewall flex in LFS's FFB, I think I'm missing the degree of feel required to make sensible decisions on the accuracy (or generation) of the tyre model.
Yes, I'm sure, but given that its not currently available to LFS, its relevance to the immediate problem is insignificant (unless the dev's are grooming a mole as we speak... ooohh errr )
Solid-axe, anti-roll bar, trailing arm and real life.
Hi! One question was bothering me for quite some time. Is simulation of suspension in LFS realistic? As You said here IRL usually small GTI dont have rear anti-roll bar, which causes the inner rear wheel to lift from the ground. Ok... so in LFS... setting anti-roll bar to 0 is like dont having it... so it should lift the inner rear wheel from the ground... but it doesn't. So trailing arm is not working exacly like RL trailing arm... is it working more like solid-axe? Btw. Is there any possibilidy to simulate solid-axe in LFS? What settings should I use[anti-roll bar
]? Thx for answers .Not having a rear anti-roll bar will REDUCE the change of lifting a rear wheel. Having a totally rigid ARB would lift the wheel on the slightest body roll. You are the wrong way around!
Sry, i said it wrong ^^. I mean in XFG we have rear trailing arm... so as in real life GTI:
it shouldn't have anti-roll bar... so i presume that railing arm is not working as it should in RL(it is not working little like anti-roll bar)? Couse when setting anti-roll bar to 0 it cerainly doesn't lift the rear wheel.
A softer anti-roll bar will reduce the wheel lifting tendency. With the right setup, and a stiffer rear bar you can lift the inside wheel quite a lot. ARB transfers load FROM the inside wheel TO the outside wheel, and if the inside wheel doesn't have much load left then it'll be picked up. After that the load is transferred diagonally.
But no, the rear suspension of the XFG is more like a sliding pillar arrangment, where the wheels move vertically relative to the car body, and suffer no camber change in roll. But for the back end of a car it's pretty good really.
But no, the rear suspension of the XFG is more like a sliding pillar arrangment, where the wheels move vertically relative to the car body, and suffer no camber change in roll. But for the back end of a car it's pretty good really.
wow this thread is still running ...
On the point of accurate modeling of tyre temps, as has been said there are just too many unknowns. Imagine if you want to really do it accurately then you're going to have to get in to the realm of modelling windflow characteristics (fluid mechanics effectively) to model the air cooling affect. Then what happens when the devs introduce variable weather and you get a part damp track? How do you work out the temp of the water? and how much does it cool down the tyre?
Personally I think this kind of modelling is way outside the possibilities of any games physics model, even if it could be coded successfully imagine the computing power that would be required to play the game !!
Best way to approach it IMO is to go out there and make some empirical measurements and then just model the characteristics of some real tyres of differing types, (radial/crossply "sports" road tyres, slicks, cut slicks, full wets etc), in differing conditions. Admittedly making the actual measurements might be difficult and probably you would have to just use surface temp measurements as you're going to need real time measurements whilst on the track. Therefore you're going to have to forget about the actual temp of the rubber througout it's structure and assume certain thermal properties to extrapolate those surface temps in to the core in a predefined way.
It won't be 100% accurate, but I'm willing to bet it could be close enough that even real racers on here aren't going to be able to tell the difference. Especially given that sitting at your desk with a wheel in your hands is never going to give you all the feed back being in a real car would anyway.
On the point of accurate modeling of tyre temps, as has been said there are just too many unknowns. Imagine if you want to really do it accurately then you're going to have to get in to the realm of modelling windflow characteristics (fluid mechanics effectively) to model the air cooling affect. Then what happens when the devs introduce variable weather and you get a part damp track? How do you work out the temp of the water? and how much does it cool down the tyre?
Personally I think this kind of modelling is way outside the possibilities of any games physics model, even if it could be coded successfully imagine the computing power that would be required to play the game !!
Best way to approach it IMO is to go out there and make some empirical measurements and then just model the characteristics of some real tyres of differing types, (radial/crossply "sports" road tyres, slicks, cut slicks, full wets etc), in differing conditions. Admittedly making the actual measurements might be difficult and probably you would have to just use surface temp measurements as you're going to need real time measurements whilst on the track. Therefore you're going to have to forget about the actual temp of the rubber througout it's structure and assume certain thermal properties to extrapolate those surface temps in to the core in a predefined way.
It won't be 100% accurate, but I'm willing to bet it could be close enough that even real racers on here aren't going to be able to tell the difference. Especially given that sitting at your desk with a wheel in your hands is never going to give you all the feed back being in a real car would anyway.
Tbh I wouldn't advise driving on a nail, it will ruin your tyres.
Awesome. So what series did you race in?
yes they do ... almost all of them ... a pretty big one in fact
This is purely speculation and just based on the feeling I've had when I've used the low powered FWD cars.
Feels to me like the hybrids on the rear allow a bit of lift off oversteer without creating as much of a 'scrub' effect. So it feels like you can get the back a bit loose without scrubbing loads of speed at the same time.
When I think about the nature of grip and tyres the first thing I think of is longitudinal and lateral grip. Is it reasonable to assume that different tyre types might vary in terms of their longitudinal and lateral grip? If so it must then also be reasonable to assume that this may have an effect on the way the tyre behaves when lateral grip is lost but longitudinal grip is maintained? Maybe this has something to do with it.
Just a hunch and I'd be interested to know if the longitudinal and lateral grip characteristics of the road and hybrid tyres in LFS varies.
Feels to me like the hybrids on the rear allow a bit of lift off oversteer without creating as much of a 'scrub' effect. So it feels like you can get the back a bit loose without scrubbing loads of speed at the same time.
When I think about the nature of grip and tyres the first thing I think of is longitudinal and lateral grip. Is it reasonable to assume that different tyre types might vary in terms of their longitudinal and lateral grip? If so it must then also be reasonable to assume that this may have an effect on the way the tyre behaves when lateral grip is lost but longitudinal grip is maintained? Maybe this has something to do with it.
Just a hunch and I'd be interested to know if the longitudinal and lateral grip characteristics of the road and hybrid tyres in LFS varies.
Good point. In real tyres there will be differences. The tread pattern for example definitely affects lateral grip, especially in this day and age of asymetric tread patterns and block shapes and sizes.
I know the tyre physics is still not finished, but I'd like to see a bit more info about the tyres in LFS, (eg width/aspect ratio/compound softness etc), when you are making the choice in your car setup. For example I had no idea that the Hybrid was a "race spec" tyre until scawen told us, (I'll admit to having not read "the manual" but then I suspect most people don't). I expect it's something the devs are probably working on already.
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Great Physics - Really?
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