[greglepore]

Ed-
I'm talking cantilever slicks-the "standard" size for a 15x7 wheel is 9.5x23x15, a 245 tire is 9.6 inches, so you give up almost no contact patch. The sidewall is very bulged, hence the "cantilever" name, to give a useful contact patch on a narrow rim for various roadracing applications with wheel restrictions. The tires are extremely low profile, and run on 15's so you get a greater gearing advantage, which was a stated goal. The cookies are heavier than Fuchs, but not by much, and this is entirely offset by the weight advantage of the tire.

The other plus is cost-you can get a set of used 15x7's for 2-300 bucks, and used canti slicks are readily available in everything from 25 to 55 compound for 300/set or so, with 70% or better "tread".

Edit-what I did miss was the 930 brakes-you would need spacers and longer studs to use cookies with 930 brakes-I have this setup on the 914-6-but the expense is offset by the wheel cost. For the street wheels, you just run open lugs to clear the longer studs.