OK, so after two days beating the living bejesus out of the C4S at Gateway International Raceway, my PZeros are toast. Time for a new set.

I'm poking around Tirerack, and everyone seems to love their Michelin PS2's, but here's my question: I'm looking at revolutions per mile, and for the stock Pirellis, the ratio is 826:801 f:r, BUT for the same sized PS2's the ratio is 829:832.

So, is the difference in ratios going to cause a problem with the AWD or PSM?

TIA

 

http://www.miata.net/garage/tirecalc.html

 

Thanks for replying, but that doesn't quite help. I'm sticking with the stock sizes (225/40/18 Front, 295/30/18 Rear), I just noticed that the ratio of circumference from front to rear differed from the Pirellis.

I looked a little more into it, and (per Tirerack.com), the ratio of revolutions per mile for the N-rated OEM tires varies quite a bit...

The PS2's seem to be within the range of OEM tires, so I think they'll do fine, but I wanted to be sure.

ContiSportContact 2 PZero Pilot Sport Ribs PS2
Front 225/40ZR18 825 826 821 829
Rear 295/30ZR18 827 801 832 832
Ratio Front/Rear 0.9976 1.0312 0.9868 0.9964

 

The 295/30-18 figure of 801 revs/mile is an error. I think the diameter figures are more accurate.