trbo2nr

I think I have answered my own question when looking for the widest rear on a stock C32 rim and looks to be 265. I have not done any suspension mods so I'm thinking 265 should be fine. Sound right?

Zeppelin

Yes you can put a 265/40/17 on the stock rear rim. It will give you slightly more contact patch than a 255 with a higher gear ratio since the tire is taller. Ideally you want a wider rim than 8.5 to put a 265 on, but it works.

c32AMG-DTM

Since the stock rear is 245/40/17, wouldn't a 265/40/17 have too much sidewall? The reason I say that is I've heard (although it may be B.S.) that if you drastically change the overall wheel circumference so the rear and front don't match up, it'll cause problems (e.g. ESP issues, "limp-home mode," etc.) I also wonder if there'd be any clearance issues... most people who're fitting an unusual size rear tire also probably have lowered their C32s...

I'd think you'd need a 265/35/17 to keep the proper overall wheel circumference... not sure if anyone even makes a tire in that size, however.

trbo2nr

ok- thanks.

Zeppelin

I've been running 265/40/17 rear and 245/40/17 front for 2 years now and have never seen an ESP failure of any kind.

e1000

the original tire size on a C32 is 245/45/17. 265/40/17's are 1.3% shorter overall diameter compared to the stock size. (which is fine)

zcct04

E1000,
The stock rears are 245/40-17, not 245/45-17
245/40-17 has a diameter of 24.7
265/40-17 has a diameter of 25.3, which is 2.5% TALLER.

Here's a good tire size calculator:
http://www.miata.net/garage/tirecalc.html

e1000

you're right. I had it wrong.