One of the tricks for the autoX setup is to use the smallest allowable wheel diameter and use short profile tires to reduce the overall diameter.  This has a similar effect to changing the gear ratio (and reduces the unsprung weight as well). 

This will throw off your speedo readings, but that shouldn't matter on the track.

As for rules on the HS - I'll leave that up to the autoX'ers out there.

Ken

Hi all

i have a 2010 mini cooper base model. I want to know what size wheels and tires i can go to and still stay is HS for solo autocross. My car has 15" wheels and the SCCA rules say that i can go +/- 1" on wheel size, however were larger wheels available as a factory option on a base mini in 2010 if they were it will give me more options and still stay in HS class

I have been told that the Bridgestone Potenza RE-71R tires are a great tire for the mini and they are available in many sizes.

what is the best wheel size, tire size, wheel offset, combination for a mini cooper base model that will keep me in HS for autox?