Correct tire for an 11" wheel
 

I just put Volk TE37 wheels on my 2000 NB 996. The rears are 11". I put the 265/35/18 tires on the wheels but they seem to be really streched. Is there a size for 11" wheels that is more appropriate for this wheel? THanks

285x30 or 295x30.

Yes, the 265s are too narrow for a 11" wheel, and I think the 285s are a bit narrow as well. You might be constrained in width choice by the overall diameter you need/want. The 265/35/18 you have now is probably about 25.4" in diameter, so the 295/30 would be a little shorter (about 25.1"). 305 and 315 are both good widths for a 11' rim. 305/35/18 has a diameter of about 26.3", and 315/30/18 has a diameter of about 25.5".

265/35/18 tires should be fitted to 9" - 10.5" wheels.