Originally Posted by DuaneC63

Really not going to make much difference in performance (might even make it worse). A 275 is taller, lowering your rear end ratio. They weigh more increasing both rotational and un-sprung mass. Assuming you get 10mm more of tread width (which you may or may not as the width number is the section width not the tread width) it's not going to make that much of a difference in handling or hooking up. Admittedly the 265 are too narrow for the drive train, but unless you punch out the rear wells and shove some 315 under there, hook up is always going to be a problem. You'll get more result in handling by upgrading to more robust coil overs. Did all the 507 come with LSD? If not, put a Quafe in. It like doubling your tread width.

Originally Posted by DuaneC63

Really not going to make much difference in performance (might even make it worse). A 275 is taller, lowering your rear end ratio. They weigh more increasing both rotational and un-sprung mass. Assuming you get 10mm more of tread width (which you may or may not as the width number is the section width not the tread width) it's not going to make that much of a difference in handling or hooking up. Admittedly the 265 are too narrow for the drive train, but unless you punch out the rear wells and shove some 315 under there, hook up is always going to be a problem. You'll get more result in handling by upgrading to more robust coil overs. Did all the 507 come with LSD? If not, put a Quafe in. It like doubling your tread width.

Originally Posted by WESLEY KAY

Why would the 275s be taller? I would still be going with 30s, not 35s. And this would be coming from a 255/30 setup, so possibly 20mm difference. I believe the rears are 30. I forget. I figured anything would be better than the 255s. The LSD was an option only on the 507. Mine did come with one. It helps tremendously.

Originally Posted by WESLEY KAY

Why would the 275s be taller? I would still be going with 30s, not 35s. And this would be coming from a 255/30 setup, so possibly 20mm difference. I believe the rears are 30. I forget. I figured anything would be better than the 255s.

The LSD was an option only on the 507. Mine did come with one. It helps tremendously.

Originally Posted by m a x i m u s

the 30 is a % of the width, so 30% of 275 is more than 30% of 265, = taller.

Originally Posted by WESLEY KAY

Soooo....507 guys and gals. I am debating the 265 vs 275 option in the rear as well. Any objections against the 275s in hard cornering on the stock 507 wheels? I will be going with the Michelin PSSs. I am thinking 265 to be safe because I do hard cornering for shizzle!! Anyone?

Originally Posted by Diabolis

Yes. During hard cornering, a 275-size tire mounted on a 9" wide rim will have way too much sidewall flex. Go with a 255 or 265. You won't notice the difference in grip, but you will definitely notice the back of the car squirming around with a 275 on the OEM rims.