[dublinoh]

Originally Posted by Joe Weinstein

Sorry, no can do. (though the equation isn't complicated...)
The rolling diameter of front and rear have to be very close
in order to be safe for the viscous differential.

Sorry, but if I picked and chose different tire brands, I might
be able to find a particular 225-40-18 and a different 295-30-18
that would not match, and could hurt the car.

If you want simple, stick to OEM. Porsche already checked things
out for you. If you want to go wider, taller, different, you (or
someone else) must check the actual rolling diameters of the
tires, by reading the tire spec sheet.

If it suits, we can make this thread into a list of tried, successful
combos (each listing would have to have the tire brand, model, and
nominal size.)

I run Yokohama Advan Neova AD07s in 265-35-18 front, and
295-30-18 rears.
Joe

Sorry for the Hijack....Joe are you on stock 18 wheels and offsets. Do you use spacers front or rear? Thanks