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Old May 8th 2014, 00:33
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Humble Humble is offline
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Join Date: Jan 2003
Location: Boulder Creek, CA
Posts: 758
I'm not going to go into what fits under what fenders only the tire/wheel combos. I think I run some of the fattest/stickiest rubber and go through 4-6 sets of tires a year on my cars. Here's what I've found.

For street tires: most summer only tires, and anything all season
205-245 on 17 x 7, 8 or 9 is the sweet spot right now, nearly every great tire comes in these sizes. Ditto for 18s but the tires cost a little more and ride a little rougher (less sidewall). If you go with 15s, a 195/55-15 or a 205/50-15 is a great setup. Very cheap tires available in these sizes and the wheels are usually nice and light.

For "street" tires: borderline street tires, R-compound, semi-slicks, and 100-140 tread wear street/track tires.
These tire need heat to work, and tire that are too big don't heat up quickly, or at all. 17" is again the sweet spot and I usually run a 245/275/40-17 in an ~1800lbs (~816kg) car and they are very temp sensitive. They are hard and lack bite below 70F (21C) so you can really feel the front slide around until you warm them up. For larger 18+ tires in these compounds and sizes I don't think it's worth it. The rubber needs to flex a little bit to heat up and when I ran my 235/285 18s they never wanted to stick below 75F (24C). If you run 15s, again 195/55 205/50 is a great, cheap (relatively), tire with lots of availability in this range. These tires/sizes suit the bug very well, they warm up quickly, without overheating, and you can surprise the hell out of people with this setup.

For race tires: full slicks, blank semi slicks (or 2 groove for US DOT)
You can run wider softer slicks than you think. The same 17 245/275 sizes apply here, and with softer compounds or hotter days you can do a 275/295 17. These types of tires require accusumps and dry sumps and sustained 1.5-2g lateral loads are the norm. Again, 15" tires here are cheap, but come in more widths and you can find 245 and 275 widths pretty easily. For track use 18" is okay since it's easier to heat them up but i would save these for hotter days if there was a choice.

I'll let you in on a little secret, sometimes with slicks, cheap trumps ultimate grip. If you have a spec series that runs at your local track, ford/lola/star mazda/formula/etc. and they run a spec tire, you can usually get take-offs for little to nothing. If you can run a 13x8/10 or a 15x8/10 you can have your pick of the lot at the end of a race day and a set of take-offs can have anywhere between 0-70 miles depending on the series.

Why haven't I mentioned 16"?
They are getting harder and harder to find in a variety of sizes, with the exception of slicks, and many manufacturers have reduced the amount of 16" tires they make or have ceased producing this size altogether.

to stagger, or not to stagger:
For a street car there is little benefit to staggered setups, and I tend to run even setups all around to keep costs down. You can't rotate staggered tires without re-mounting and you can't get as much life out of them at a greater cost. For racing, cost isn't as much of a factor, and more rubber gives you better braking and better drive out of corners. Tire life is less important when racing because tires typically heat cycle out before they are worn out.

15" or 17" in 195-245 good. 18" okay when racing, or in warm weather. 16" bad Stagger good for racing but expensive on the street. Spec racing series tires are almost free so use them if you can.
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