I was wondering if 255/45/18 tires would be suitable for the RX-8, on the stock rims. Anybody have any experience with that size on all four wheels? Are wheel well clearances adequate? Any notable trade-offs in handling, adhesion, etc.? FWIW, I was looking at the Michelin Pilot XGT Z4, and hoping that it would be OK for occasional light snow/ice. Any advice would be appreciated. Thanks! MARK

 

I think 245s are as wide as you should go for everyday driving on the OEM wheels. For 255's you would probably need to go to a 8.5' wheel.

 

^^^ I got 255s on my 18x8.5

 

Two big problems - first, 255/45-18 is one inch larger diameter than the stock 225/45-18 - that will throw your speedometer off by 4%, and slow down acceleration of the car as well.

Second, for snow/ice performance you need narrower tires, NOT wider! While all-seasons in general will offer better occasional snow/ice performance than stock summer performance tires (they'll still be pretty crappy, but that's better than horrific!), the 255 width a/s tires will be noticeably WORSE on any snow/ice than 225 width a/s tires would be.

I wouldn't consider that size. Even for just dry pavement performance, they're too tall. For wet or slippery (snow/ice) pavement performance, they're too wide

Regards,
Gordon