Lots of great information which mostly correlates with my experiences. I've raced competitively in both a GTI Cup and ITB Capri on Toyos, Kumhos, Hoosier 03s and 04s and Goodyear GSCS tires.
Toyos - approx 1.5 to 2 secs/lap slower on a 2:10 laptime track called Thunderhill. There are quite a few sweeping turns that keep the car at the edge of traction through 90 degrees and the Hoosier/Goodyear just grips so much better. At a technical transition track like Sears Point (Infineon), the difference is closer to 1 to 1.5 seconds. BTW, I've been racing GTI Cup this year and my newest Toyo was manufactured in the year 2000 and they still work great. I don't know how many heat cycles but I got them all used from a retired racer. The grip seems to drop off just before they start to cord.
Hoosiers - 04s work a bit better but I think that is because I have to use a 6 inch wide rim. 03s are just as fast when I put them on 7 inch wide rims. Even with careful tire breakin, I find that the tires are noticeably slower on the 6th heat cycle. By the 8th heat cycle, they are about 2 secs/lap slower and go away pretty early in a race. I might also mention that I notice very little tire wear. After 6 heat cycles, tires are barely worn.
Goodyears - same speed as the Hoosiers and tire wear is more noticeable. Tire life seems to be better than the Hoosiers and they are more resistant to flat spotting. I've run them up to 8 heat cycles when they look pretty worn.
Kumhos - wear seems 25+% faster than the Toyos and lap times are about the same on the Capri. Kumhos seem faster on my FWD GTI but I don't have any hard data. I prefer the Toyos overall as compared to Kumhos.
I'm running the NASA 25 hour enduro in my Capri this year and I will be using up all my 6 heat cycles Hoosiers and Goodyears!
I should also mention that when I say 6th heat cycle, I had already counted the breakin as the 1st heat cycle so these tires are basically finished in one weekend if one wants to win. Of course, they are used for 2 weekends to allow them to cool and properly break in .
Joe Craven
71 ITB Capri
72 ITA Capri
77 GTI Cup
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