225/45R18

[Daiji]

Currently I am running 225/40R18s on the front of my 1999 996 C2, and 265/35R18s in the rear. Due to clearance issues on the front end getting in and out of my driveway, I was thinking of going to 225/45R18s in the front to get a little more clearance. Is this doable? I've heard that it may cause PSM/ABS problems.

[Chumly]

I went have the same wheel size on my 04 996 and I went to a 19 inch wheels with 235/35 on front and the inch difference in height made ZERO difference to PSM/ABS. That is my two cents...Chumly

[Loren]

You need to check and see how much the overall outside diameter of the tire changes.

Porsche says within 5% is okay.

[therock88]

So...To Loren's point, if you have a 5% deviation allowed the following would apply:

You have current total diameter of 18" + (2 X (.40X 225MM) = 18" + (2 X (.40 X 8.858") = 25.0864" Diameter with your existing set up.

You can add 5% which would allow 26.34072". So your suggested set up with 45 ratio tires would put you at 25.9722", so you should be OK assuming they fit in your wheel

opening OK.

Hope that helps!

DC

[Daiji]

To All,

Thanks for the information.