Proper 18" tire size for 10" rear wheels??

[ktee]

Hey there,

I ordered 18" Italian replicas (8" front/10" rear) for my summer tire set-up and installed winter tires on my factory 18s. I was planning on installing the factory rubber (265/40/18) on the new wheels, but my installer told me that those tires are not wide enough for the 10 inch rear rims. When I look at Tirerack, I don't see any 275 or 285 18s that are Porsche rated.

Need some help - thoughts anyone??

Thanks,

Steve