Hi all! something thats been puzzling me now quite a bit is tyre wear. Now, I do know that there is tyre wear but they only wear out until a puncture happens, not lose grip over time because I remember while practicing for an IGTC race, I could get a lap round AS Historic, mid-way into my stint (30 mins), of 2:20.7 and then as I was near the end of my stint, 1 hour in, I got 2:20.2 so there is something clearly wrong there. I know that tyre physics aren't exactly 2+2=4 kind of mathematics but still, there should be some sort of tyre degradaton over time because like this, if a driver can get the tyres to last for the time that he needs, he can gun it 100% all the way through, always getting the same lap times and removes a vital part of race strategy.

No, there is no loss of raw grip due to wear in LFS, probably due to the lack of real life data to make accurate formulas for it. In LFS, you're actually faster with worn tyres, since you can abuse them much more without overheating them and they have less mass.

Also towards the end of your stint you will be alot lighter and into your groove.

Even if the tyre model is flawed in that aspect, I think those laptimes are more due to an lighter fuel load at that stage than the tyre wear

Structural degredation of the carcass, devulcanization of the rubber, and loss of rubber material from the tread. If I understand correctly, these are the three aspects of "tire wear", but I don't think the actual loss of material has anything to do with the grip reduction IRL. In LFS, the first two aspects are not simulated, so there is no grip reduction. The contact patch may be smaller but that's offset by the reduced heat capacity of a thinner tread.

Other than overheating my tyres (through excessive sliding ) I've not really noticed the degradation of my tyres within a stint in real life.

However, this has some clauses:

1.) I'm not good or consistent enough to lap at the same pace every lap regardless of tyres or other factors, so if the tyre does degrade it's not enough for me to feel. Overall my lap times tend to get quicker over a race, not slower, although this is also due to the fact I'm still learning aspects of the track.
2) My races are short
3) We use a relatively hard compound to last a bit longer into the season.

It's heat cycles that, apparently, make tyres go slower, although all the real-world data on this is from race teams that throw tyres away after a couple of runs max anyway. Personally I think age is the bigger killer of tyres, and exposure to UV light.

There is alot of variables to consider in tyres.

I personally think that like alot of things implemented in LFS they work well within the range of normal racing but don't necessarily follow how rl tyres would behave outside normal race use patterns.

I think with the slicks in LFS there is a reasonably believable heat cycle throughout a race. I do think that fresh tyres should be grippier than slightly used tyres and yes tyres should have a more dramatic change in grip levels when the rubber gets really low as its likely to be a different stiffer compound and be running on the webbing structural materials before the tyre pops although in a racing environment the transition is likely to be pretty quick.

With road tyres it is likely to be quite different in some areas. New fresh tyres still should have alot of grip, but new tyres should be prone to overheating the tread blocks and give larger slip angles than partly worn treaded tyres, partially worn tyres would give more stable heat characteristics and feel firmer more confident in corners. How road tyres heat/cool during there life time most likely should change alot more than slicks due to variying amount of flex in the tread blocks and potentially increasing amount of rubber in contact with the road as the tyre wears depending on the tread design.

Damn I'm slow at writing, what forbin and tristan said also

I've noted in the V8Supercar field they often refer to fresh green tyres to having alot more grip than tyres that have done a stint. So the characteristics of the control tyre they use must change quite alot from new to used condiition even within the race - not accounting for heat cycles.

well... generally there isnt a reason for used tyres to have less grip... slicks have rubber on rubber, so up to the point when you are rolling in the structural mesh, you are always driving on the same rubber, so you should have the same grip (for the same temp). For treaded tires its different - the more worn, the more grip, cause it begins to resemble a slick more and more.

In road cars, since when the tire is reaching its "slick" phase and needs to be changed (unless you are 100% positive it wont rain, nor will you find any pebbles/sand/small stones on the road), you SHOULD have more grip.. but you don't. This is cause by the time the tyre reaches its slick phase, its 2-3 years old (lets say 40'000kms), and the sun has cooked it till its much harder than before. It is also much more brittle - you can see this by looking at the sidewalls of an old tire - between the sidewalls and the treads, you can see small "cracks" in the rubber - it has hardened, and provides a lot less grip.

It IS normal to have faster laptimes at the end of stints- even in RL - just look at f1's times (the easiest to find laptimes) - they do good laps all during the sting, and the times usually shrink (due to a lighter car as it burns off fuel). Only on long stints the last laps aint that fast, cause a) driver is conserving whatever left is of his tires b) driver is nervous his tire might not last and propell him headfirst into that hard hard wall at 200kph and c) tires are very cold, cant heat up, and provide less grip. Usually all3.

Takes a special driver to really take advantage of the cold end-of-life tires and the light fuel load and make some mind-boggling fast laps (schumi/senna etc) - one that knows just how much the tire will still last from the feel it gives - from the temperature its at (taken from how much grip its giving), and for how hard its been pushed, then estimate if it will last just one more lap or not