Will a 255/40 fit on the OEM 8" rim? I've seen the specs saying that the minimum width is 8.5" for 255's but can a tire shop put them on anyway?

Or should I just go with a 235/45...

I dont want to go with 225s again. They're really skinny.

Thanks,
Sean

I am going for the 235/40/18 Pirelli right now. The best size is 245 or 235. I THINK 255 is too wide and you will lose your acceleration.

235/45 or 245/40.

I am going for the 235/40/18 Pirelli right now. The best size is 245 or 235. I THINK 255 is too wide and you will lose your acceleration.

255/40 is within 1% diameter of stock.. I don't see how this would decrease acceleration by any measurable amount?

235/40 is 3% less talll than stock which means when the speedometer shows 80 you'll be going about 77.

245/40 is probably the closest match for diameter in a plus size at only about 1% thinner than stock.

Does anybody know if 255 will fit without rubbing issues?

Most any tire shop should be willing to stuff 255/40 on your 8-inch wide wheels.

If you're going to keep the suspension stock, you may be alright for daily driving. You'll probably rub with spirited street driving, and definitely rub autox/track day.

The size marked on a tire's sidewall is for guidance only... actual measured overall diameter, section width and treadwidth will vary from tire model to tire model, even within the same manufacturer's line. Wheel width will also change actual size, although not tremendously.

From TireRack's specs, the Michelin is .1" taller than OEM (25" vs. 24.9"). One of my wheel/tire sets is a 225/45 mounted on 8.5-wide 17s. The specs say they should be 25.2" on a 7.5 wheel. They measured out at 25.25" on my 8.5, and they were shaved to 6/32nds!

Any performance "drop" from this taller tire was more than offset by a lighter wheel (the overall package was 7 pounds less per corner).

My street set is 245/40 Pirellis mounted on 17x8.5, and they are exactly the same height as the OEM tires worn down to 7/32nds. TireRack's specs put the Pirellis at 24.7" diameter. I measured them at 24.875" -- and they do not rub in daily driving (Eibach springs and rolled rear fenders).

Full rundown of specs and pix here. (http://forums.nasioc.com/forums/showthread.php?t=650672)

ymmv.

235/40 is 3% less talll than stock which means when the speedometer shows 80 you'll be going about 77.Keep in mind the STi speedo is already like 5mph off at that speed (says 80, you are really only doing maybe 75) - so a smaller diameter tire would make it even worse. A slightly larger tire (235/45) would help correct it a bit.

I am considering selling my set w/5000 miles.
http://forums.nasioc.com/forums/showthread.php?p=8074269

I am running 255/40/17 Kumho Victoracers on an '04 STi 7.5" rim. Fitting 255's would not be a problem on a '05 8" rim. I have no clearance issues on a completely stock suspension, but the clearance in the rear is about 3mm to the strut. For street tires, I would recommend 245/40/17. Good luck.

I am running 255/40/17 Kumho Victoracers on an '04 STi 7.5" rim. Fitting 255's would not be a problem on a '05 8" rim. I have no clearance issues on a completely stock suspension, but the clearance in the rear is about 3mm to the strut. For street tires, I would recommend 245/40/17. Good luck.

do you think 255 on an 8" rim would be usable? as in, would the sidewall squirm and everything?

the 8" rims are intended for use with a 235 tire. If i go up to a 255 i should have no problem... right?

And considering the wheel's wider I should haevp lenty of clearance with the shock.

I am considering going to STI pink springs, though.

Would a 245 or 255 Michelin PS2 grip better than 225s RE070?

Thanks,
Sean

In my understanding, the wider the tire, the more grip you get. So, 255 is better in grip.

Of course, brands and quality matter too.