Hey guys

I just bought two near rears for my 2006 S2000. I have Sumitomo HTR Z II's up front, and just bought new HTR Z III's for the back. My question would be, are both these Sumitomo tires interchangeable? Or should I go ahead and buy the HTR Z III's for the front as well? The reason I didn't buy the fronts is because the HTR Z II's are at about 90% Tread.

Thanks guys for any help!

 

Pretty sure ZII are a different category tire that will not be as sticky as ZIII. So it it will probably under-steer more when pushed, you could always try it and see how you like it.
Or you could match and just sell the current fronts on CL.

 

My car had HTR Z-III's. Since I'm 400HP, tires, especially rears, don't last very long. They handled just fine. However, I found them a bit stiff and the car had a "jittery" ride with them. I've since switched to Hankook Ventus V12 evo2's and they have a much better ride and much less responsive steering due to softer sidewalls.

I'd guess that the tire set you have will work out just fine.

 

The difference between the II and the III is relatively small. Mixing them front to back is going to be fine. You definitely do not want to mix them side to side, however.

 

Actually, the case could be made that a side to side mismatch is "safer" than front/back mismatch, since while cornering either way you'd have the same grip capability at the front and back of the car and should be balanced, although you'd have different ultimate grip in left-handers vs. right-handers!

If there's a front/rear mismatch, the most important thing is that the rears should have equal or greater grip vs. the front for *all* conditions that the car may experience. ZII fronts with ZIII rears probably meets that criterion.

Personally, I've run many different front/rear mismatches while trying to adhere to that approach and have never had any issues in the wet/dry on the street/track, and in the snow on winter tires.

 

The problem is that if have a side to side mismatch and you exceed the traction for one of the tires, the car will tend to rotate. This applies for both heavy breaking and heavy acceleration - notably in the rain. The last thing you want is your car doing a 180 in a rainstorm because you hit the gas and the tire on the right let go before the one on the right. You're far safer if either both let go at the same time or neither of them let go at all.

Since these cars are not inherently neutral (especially AP1s), then having a stickier tire in the back than the front usually isn't an issue.

 

^^ Yup. I wouldn't necessarily condone left/right mismatch, but the argument could be made! You would definitely want to make sure that the tires were well-matched performance-wise for all usage conditions in that case.