Comparing 986 and 987 tire sizes

[stephen wilson]

Not proper setup? Most performance and racing cars have rear tires that are wider and taller. It's always harder to find grip for acceleration than for braking. The rear tires also have to provide the driving force to overcome aero/cornering drag, which reduces grip available for lateral acceleration. The Corvette and Elise even have larger diameter rear wheels.

[WhipE350]

Originally Posted by stephen wilson

Not proper setup? Most performance and racing cars have rear tires that are wider and taller. It's always harder to find grip for acceleration than for braking. The rear tires also have to provide the driving force to overcome aero/cornering drag, which reduces grip available for lateral acceleration. The Corvette and Elise even have larger diameter rear wheels.

Kewl...did not know the racing setup has taller wheels/tires. Interesting.

[stephen wilson]

Yes, you do have to be carefull with relative front/rear diameters. I put 245/40-18's on the front of my 987, whick worked well to reduce understeer, but if I raise the front pressure more than 2 psi , it's makes the PSM kick in all the time.

[stephen wilson]

To your point, I would stick with the 265/40-18 on the 987, there's no reason to go to a 265/35.

As far as the 986, the 265/40's are 1" taller than the OEM tires, I would verify that others have run them without issue. Of course, you could just swap wheels for a while, and do a little "testing" to see if there is any ABS problems. You would probably have to live with the speedo being off.