LOL. MJ&JR, you guys read my mind, was pondering on same question for 2 days now but I'm not so sure about your statements.
I had an off during the race (which reminds me, must check replay and do a thorough report on this GT1 sprint, awesome race, probably best one so far) and I did get a huge loss of grip for almost a lap or so. Then again, GTRPD2 did show front tyre temp drop - a lot (more importantly - tyre pressure drop).
It's a complex issue anyway. You lose front tyre grip (due to an off - tyres cool down, due to being stuck in traffic - tyres cool down, due to easing off to conserve tyres - again: cooled tyres, it's usually the fronts that cause the trouble) since they're cold - classic catch 22. Cold tyres, you get careful, hence you take different lines, perhaps brake early and not abuse the fronts so much and voila, they cool down even more...
But (there's always a but, right?
), now here me out:
- there are certain "magic tyre wear benchmarks", numbers vary depending on the type of tyre, but nevertheless, they're there. Softs have, erm, I call them "stages". 0-7 (or so)= excellent grip; 8-13/14=average, 15-18/19= less then average, 20-27=careful now, careful, 27-onwards= grip? what grip?
Right?
Anyway, thing that irritates me the most is transition between the above mentioned "stages" - it's far from being gradual, no warning at all, your fronts go from "grippy" to "yeah yeah, I'll turn in... eventually" in an instant (tyre wear 18 or so with softs, or 15 with mediums). Same goes for track temperature issue, magic number is 27 degrees celsius. Huge difference between times achieved @ 26 degrees and... say 28 or so. It's not gradual at all. Best thing to describe it would be: it's not analog but digital...
Unfortunately (during my in race off) replay does not show any damage on front splitter/aero, I hit sand rather hard and front grip was gone afterwards, there is no way tyres were sooooo worn out (below 20 at the time, I think it was lap 16-17), so it's hard to judge was it due to tyres, tyre temp, aero damage or simply dirt on tyres, but I do know one thing: remember how, in case you hit a curb very hard or something like that, your car starts to pull to one side or the other or you get vibration or similar? It does last about a lap or so, then it wears out and kill me if I'm wrong, but I get same feeling with dirty tyres (due to an off). Every bloody time, even if you do NOT lose tyre temp, grip simply isn't there for a certain amount of track time.
Right. Confused text, I'm sure, but here it is just the same. Short version: I think track excursions DO get your tyres dirty, I also hit marbles few times in that looong lefthander after the fast chicane (i.e. went very wide) and suffered major understeer problems up until getting into T3 (which is something like half a lap or so later), then it went back to normal once I got to... Adelaide (give or take, happened 3 times, same effect, every bloody time. There must be something to it.).
