Also great job on not making the contestants send in the answers via PM :rolleyes:

But these are things you do once, not often enough to constantly run out during the week.

Think of it as your unlock-account. The maximum value this account can hold is 2. Every Friday you get +1 spare unlock (or is it +2 already? I'm not sure), filling up your account up to its maximum value. Should you, for whatever reason, use all these unlocks during the week, you'll have to wait for Friday to get new ones. In "emergency" cases you can also write an email to the devs to re-up your unlocks.

In practice you don't really need those unlocks anyway, though. Once you unlock your account there's never a reason to lock it again.

Quote from The Very End :

Also, you should be carefull giving too much restriction

You're just whining because you're a weirdo who races with chase cam

Guys this debate is entirely superfluous. Scawen knows that the tyre heating, wear and compound selection/behaviour are not finalised.

It's spelled license. And you're just going to get drunk again and give it to some random person anyway

I'm really not sure what you're pursuing here as a whole? Seems to be a whole lot of effort for nothing really

I think it's pretty clear that the tyre wear itself has no direct physical influence on the car's performance (in LFS). All the factors you're speculating about here are far to small to have any serious impact on laptimes, compared to the uncertainty factor that is human control, or other actually big factors like tyre temperature or fuel weight. If there was an artefact, a physics oddity, then somehow it would have to be big enough that untalented drivers (relatively speaking) benefit from it, too, for it to be "noticed" so widely. And if it were that big, you'd see all world record laps taking 60+ laps beforehand to wear down the tyres to get this then very tangible advantage of having worn tyres, and I'm pretty sure hotlappers do anything to set a WR

Honestly, I think it's more to do with ones mind than having an actual physical reason. You want to believe... no, you know that a worn tyre makes you faster so in the end you are faster. Suddenly in your mind the worn tyre actually made you faster, whereas it was probably just you believing in yourself resulting in better driving. And with that you have the self-reinforcing "evidence" of worn tyres making someone faster, where there can hardly be found any measurable effect of tyre wear itself.

Comparisons of LFS to real life are also somewhat useless. While LFS is quite good and complex in general, if you start going into the details you just notice more and more areas that very much matter for racing are only very roughly approximated if simulated at all. Tyre heat and wear is (officially) a very WIP part of the simulation, with most behaviour being barely more than educated guesses. I could now list all the obvious deficiencies of LFS' tyre model, but really there's no point. Making a fully abstract model of a tyre where in the end the correct behaviour just falls into place is, while noble, not really realistic in terms of being a reachable goal either.

Right now, I think LFS in terms of realism is so close, yet so far.

Impossible. Reading the speed would be a piece of cake, but there's no way to do a useful speed comparison on an almost full and empty fuel tank. Also there's no track on LFS where you can reach air-resistance limited top speed. The oval comes close, but not quite - even there it depends on how well you exit the last corner. Besides that, the AI absolutely sucks at the oval (it was actually braking there on the KY Nat run :doh:)

Anyway, did a "quick" test with one FZR AI on KY Nat, letting it drive 2hrs on R3 slicks. The maximum tyre wear was reached at about lap 35, in which it did a pitstop to refuel where it also changed the tyres. From looking at the wear of the F9 view, it seemed like it was worn about 30-35% - it was definitely over 30% though, as the AI set its pitstop strategy to change when worn > 30%.

Looking at both left and right rear tyre data (lateral grip vs. slip angle) and comparing lap 6 to lap 35 shows that there's definitely NO change in tyre behaviour by wear (as I suspected, to be honest). The curves looked pretty much 99% identical and the tiny difference can most likely be attributed to a difference in tyre temperature, air pressure and/or car weight.

Well, I guess if they record their tests in single player mode...?

Quote from Neilser :

AND, I've just realised that your super-cool tyre data-gathering technique could actually help prove what's going on here

Of course doing a RAF extract of the worn tyres could bring some light into that, but... the problem is to acquire worn tyres in the first place. Heating them or changing pressure is something that can be done in a minute, but wearing them down is a far more daunting task.

The easiest way is probably to let the AI drive lots and lots of laps on a balanced and not too difficult track, though if the AI pits for refuelling or crashes (doing a reset) all the wait would've been for naught. Even if it succeeds and wears down the tyres, it could happen that it simply doesn't use the tyres in a way that provides useful data.

Quote from AndRand :

And how can you achieve better laptime by this?

The smaller circumference certainly doesn't help you achieve better laptimes.
However when the tyres are worn down likely following things happened:

1) You drove for a quite long time and are more likely to be "in the zone"
2) The tyres have less heat capacity, cooling down from the usual overheat phase thus enabling you to go faster after having to drive careful
3) Your fuel level is lower than on race start
4) The tyres behave differently somehow (???)

Quote from Neilser :

Wow, never noticed that. But I guess it doesn't modify the circumference?

Errr, the bumping is a direct result of one section having a smaller radius than the others. Of course if all sections are worn the wheel diameter and with that also the circumference decreases.

Theoretically, if you have a tyre with a radius of 30cm (23.62'' diameter) it needs to rotate at 884.19 RPM to achieve a wheelspeed of 100 km/h. If you wear down this tyre by half a centimetre to 29.5cm radius, the required RPM increase to 899.18, or if you rotate the worn wheel at the same RPM required for a non-worn one, the wheelspeed will be 98.33 km/h.

However, do note that the speedo in LFS works by measuring the speed at the differential / wheels and simply assumes a certain tyre circumference to calculate the actual speed (like real cars do). If you drive a car in 5th gear at 5000 RPM the speedo will always display the same speed regardless of how worn or inflated the tyres are. Now if you had a GPS like system that showed your actual velocity, it would be clear that you're actually moving at a different speed than the speedo displays with worn or differently inflated tyres.

Last edited by AndroidXP, Sat, 8 Aug 2009 09:09.

Quote from Neilser :

Indeed. I agree worn=lighter tyres should make almost no diff to the car but a smaller rolling radius should be trivial to spot. But I think this effect is definitively absent or I'd (surely!) have noticed it by now...

Now that I think about it I'm not so sure about the weight reduction anymore, since as you've all pointed out the difference would be minuscule.

However the radius of the tyre changes and that is even quite easy to verify. Simply make a setup with ridiculous brake strength, get some speed on a straight and mash the brakes to create an enormous flatspot. Instead of being a real flatspot, LFS simulates this (rather poorly if you think about it) by wearing down the affected tyre pads. If you then drive very slowly - preferably in wheel-only view - you'll see the tyre bounce up and down as it rolls over the worn-down pads/section. Actually, this is what I'm talking about:

No idea about Tweak though, I haven't been keeping up with LFS for quite some time now. Heh, two seconds later I find this.


@AndRand: I don't have the source graphs for that anymore, no, though I don't believe the heat changes the grip characteristics much at all. It seems to be more of a static grip modifier scaling the grip/slip curve up and down the G-force axis.
What makes quite a difference is tyre air pressure relative to the weight of the car. At low weight/high pressure the rising grip line to the peak/plateau is steep and the transition sharp, whereas a high weight/low pressure the grip rise is flatter and the transition much more gradual and smooth.

- This is how a grip/slip curve looks in LFS in general. Note that these are all lateral grip curves - the longitudinal grip curve looks pretty much like the pre-U lateral curve to the right.

- Here I found an old tyre pressure grip curve comparison, see that on a high pressure the grip peaks at about 6° slip whereas on the lowest pressure it reaches the maximum at about 10°. The difference visually doesn't look too great here mainly because the line was probably taken with the FOX, which is pretty lightweight so the tyre pressure had less of an effect.

Last edited by AndroidXP, Fri, 7 Aug 2009 21:45.

Quote from Neilser :

Wow, I had never noticed those teeny weeny blips in the corners of the tyre-temp pic.

How do you know for sure it's the rim and that it's modelled? Did you find it mentioned in docs somewhere? Does the whole wheel get modelled (heat reservoir with hugely more mass than the air in the tyre)?

I know this mainly by messing around with Tweak and the tyre sizes. With a different rim size you see different parts of the tyre in the F9 view and it becomes more apparent. Also driving around in a high HP & several ton car heats the tyres just by driving (especially the sidewalls) which made me first notice that there's a rim down there on the F9 view. Seeing that a bit later the rim suddenly had the same colour as the sidewall made it clear that its heating is modelled.

Quote :

Two things to add to this:
1) I'm interested in the tyre-wear vs. grip (and temperature) effect.

As far as I know tyre wear does not affect grip at all. It does, however, affect the weight of the tyre (relatively sure) and the heat capacity (100% sure), the former meaning that with worn tyres you drive a lighter car which goes faster through corners, the latter allowing you to punish the tyres more since they can't hold heat as well and therefore won't overheat as readily.

The temperature however does have an affect on grip (duh), though the graphs are most likely outdated by now.

Quote :

LFS doesn't provide a wear-level indicator

It does (click the picture on the right). Just not a numerical one.

Last edited by AndroidXP, Fri, 7 Aug 2009 14:48.

Holy tinfoil batman, the torrent is most likely only there as a sometimes-slow-but-reliable backup in case the regular servers shit themselves, which usually happens on a new major release when everyone and his grandma downloads the new version at the same time.

Personally I avoid torrents whenever possible, simply because they often take quite a while to get going and even then the acquired speed is often less than stellar. They also don't tend to last very long and once the seeders are gone you're SOL, but for release day they can be invaluable.

FYI, the only car in LFS with a sequential gearbox + paddles is the BF1, all other sequentially shifted cars are actually simulating a sequential gearstick, where it is impossible to engage both the up and downshift at the same time.

Reading isn't your strong point, is it? The scripts linked in the 2nd post will rebind your controls to the correct configuration depending on what car you leave the garage with. After that you just have to switch your shifter to the correct mode and that's it.

In case that's still too complicated for you, go to <LFS install folder>\data\script, open road.lfs, sequential.lfs and paddle.lfs with a text editor (notepad) and copy/paste the script code from the LFS Manual page to the corresponding *.lfs file. Save, close and you're done.

Tried this waaaay back when it made its first appearance here on the forums and... it was a pile of garbage.

Obviously I haven't tried it since then and I suppose the input handling, performance and especially physics have at least improved somewhat (steering wheel had a friggin' non-removable deadzone at the centre back then), but I think the guy behind this spends too much time adding badly optimized graphics features and "tweaking" the physics rather than doing proper research and creating a model that works reasonably well if you put in the correct non-imaginary numbers.

If you watch the 2nd video on the website you'll see him "tweaking" the physics of this MRT looking car - while the game hilariously runs at about 3-4 fps. Now this might be due to video recording and not the way he does stuff normally, but I suspect that's how most physics development is accomplished in that game. The presence of, as already mentioned, several physics files for racing, drifting, etc. heavily suggests that it's mostly of a "pull slider till it feels right" kinda approach and that neither of those physics work correct (as he wouldn't need multiple then).

I don't want to diss the effort but I can't see this become a serious racing simulator anytime soon, if ever.

Sorry to burst your bubble, but the maximum real speed in LFS is 720 km/h (or 200 m/s) before it resets your car, so your tweak actually doesn't live up to what it claims to do

LFS Manual: Automatic shifter ... (for Logitech G25 users)
(Note the text in italics )

For handbrake reassignment, follow the guide above and just add this in...

road.lfs:
/button 4 handbrake

paddle.lfs:
/button 9 handbrake

sequential.lfs:
/button 4 handbrake

This will make the right paddle the handbrake when in H-gate or sequential mode (IMO closest feeling to "pulling a stick" for the handbrake when the gearstick isn't available), respectively pulling back the sequential stick when using paddles. Of course you can also use other button numbers* if you want a different configuration. If you want to simulate a rally car (in for example the RB4) then once on the track you should open the chat window and type "/run paddle" or "//paddle" which will put you in paddle mode.

* To find out the number for a controller button, go to Options > Controls and press the button in question. You will see the button # and currently assigned function in the middle right part of the screen.

Quote from The Very End :

i shit out words

qft

The setup pressure is pressure at optimum air temp, not cold temp AFAIK.

It is in fact the rim and LFS also models its heating.

^ Ohh nice, that could be it. However, in that case the question arises why Windows doesn't regard the constant HD activity as reason enough to not shut down the HD?

Hey hey, it's an SNES, you have to follow proper terminology here

Also this is so true, it's unreal.