Street or R-Compound Tires?

[MikenOH]

The 987 18" rears are 265/40/18 with a OD of about 26.3"; the 275/40 is 26.6".

The std. 987 18" front is 235/40/18 with a OD of 25.4"; the 245/40 runs about 25.6".

So by moving up a 245/275/40/18 combo, you keep the same rough proportions between the two tire sizes. This tire combo size is very popular with the Cayman crew.

[jsceash]

Wow! sorry I didn't know the tires between a 986 and 987 were sized so differently. Mine had the sport Boxster SII wheel option from new and came with PS2, 205-50ZR-17 and 255-40ZR-17.

[thstone]

Sorry, I should have mentioned that my wheels are also the 17" and I've been running 225/45/17 front and 255/40/17 rear which seems to be what most of the Spec Boxster guys run.

[jsceash]

The Hankook tires were an improvement. In a 28 Min sesssion they gained about 10 #. The Times Through the session did not fall off. With the exception of the first lap every lap was in the 2 min 39 sec range on the last session of day 1 Best time I ran. The second day we worked on brake points all 4 sessions. The PS2 started to fall off after 5 laps.

[Pat]

I'm surprised no one has mentioned oil starvation yet in this thread. Especially considering the "slippery slope" comment.