roadtripper1

Is it much of a problem or are there issues in using 265/40/18 tires on 18x11 rims for Cayman S rear? The tires I have looked at give 10.5" as max width in their spec.

As part 2 of the question, what changes in handling might we expect with 275/40/18 on the rear with the 11" rim (in spec), That tire is about 1/2" taller with of course a slightly wider tread, and a bit more sidewall depth. Rule of thumb would be a little more rear grip, hence oversteer tendency, but the taller sidewall would be less responsive on turn in etc. Real world effect is perhaps not detectable?

danschy

Can't give you any expert tire guidance, but I assume the issue would be that the tire might not seat properly in a too-wide rim. There is someone from TireRack that occasionally posts on forums and might have an answer (maybe he is more on the P9 forum). Also, more grip in the rear would increase understeer, not oversteer, but I doubt that small a change would much matter in the real world. If you look at revs/mile on different tires of the same size, which would correlate directly to effective diameter, there is considerable variation. I had to tweak my tire sizes slightly when I replaced them due to availability.

roadtripper1

Oops, I meant understeer, of which I am not at all fond. Thanks for the advice. Will also go to planet 9. I guess I should call tire rack also.

olegd

In my opinion 11 inch rims are too wide for Caymans. I had them on my car and didn't like the look or handling with them, BUT those also came with 305 wide tires! I think it depend on what type of driving you'll be doing. On the track you want the best possible fit of tire to rim to avoid tires falling off rims. I've seen that happen to a GT4 recently, the results were not pretty!