My OEM tires are 225/40/45/17 (front) and 245/40/17 (rear), I believe they are Pilot Sport.

I am buying the tires soon, probably Bridgestone S-03. I just want to increase the rear to 255/40/17 but keep the front the same size. Any big problems with this setup?

That diameter is a bit too big. I would stay with the stock size, and go with stickier tires. I have had both the S03s and Pilot Sport PS2s, and the PS2s are far and away better.

Thanks.

I think the 255 would be fine, but I think what aaronC might be trying to say is that the tire is a little too wide for the rear rim width you have.

I think the best tires are the BFGoodrich T/A KDW tires. They are the stock tire for wet use in the SCCA TransAm series. They are borderline drag radials, but have excellent side loading characters and tenacious grip with a fairly good treadlife. They might be a tiny bit noisier than what you have now though. They make sizes for your stock setup on the C32, and should accomplish more grip than the PS2 tires.

i think both are great tires, s03 and pilot sports, but they are expensive. i was really happy with my toyo t1-s, cheap, low-noise, sticky, pretty good wear, and looked cool :p . not to take away from the aforementioned tires, but if you are concerned with price, the t1-s are hard to beat from my experience. they were cheap and i loved them, found them just as good as the oem pilot sports - perhaps even quieter and well worth it

I would recommend going with the same size. 255s in the rear will be ok, but you'll probably see some tire buldge, which will also effect the ride.

The reason that I want to choose the buy the S-03, because there is a local guy here selling his tires cheap from his Z3. However, I consulted with one of the guy from tire rack and he suggested stick with the 245. The reason is the tires may be too wide and affect the speedomter and odometer of my car.

So, too bad, I cannot make the deal with that guy.

255/40/17's in the rear will be just fine. Numerous people here on the board are running them with no problems including myself.

Too bad, the seller just informed me that the tires are sold.

Thanks guys.

Well, they are probably too wide too, but I was talking about diameter. The diameter is not too much larger, but it is larger, so it is somthing to be aware of.

The stock sizing specs on a 245/40/17:
Diameter - 24.7"
Radius - 12.4"
Sidewall Height - 3.9"
Circumference - 77.6"
Revolutions / Mile - 816

The specs for the 255/40/17:
Diameter - 25"
Radius - 12.5"
Sidewall Height - 4"
Circumference - 78.6"
Revolutions / Mile - 805.7


BTW, the KDWs suck big time. They have a very hard tread compound. The tread design is the same as the Trans Am tires, but not the compound. They are not even in the "Max Performance" tire category. They are "Ultra High Performance Summer". The KDs, on the other hand, are amazing dry tires, but do not do rain.

Anyone running Michelin Pilot Cup competition tires must use 255s as they do not make a 245 for the rear. I have used them for 3 years on my 2002 C32 without any problem, except it increases the understeer. It would help if they had 235s to fit the front.

Anyone using Toyo T1-R (255/40/17) while using 225/45/17 on the C32?

There is a guy selling a set.