I posted this over in the ITR forum with no response. I thought maybe people here would be interested in discussing.

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I know lots of people that run different tire sizes on wheels with the same width (225f 205r for autox) and I know that some cars use wider wheels (matched with a wider tire) in the rear of the car...

While reading through SCC this month I noticed an interesting twist to the above scenarios. They were test driving a few EVOs and WRXs (both track and street) tuned by BOZZ Speed in Japan. One thing this tuner did was to run wider wheels in the front of the car and narrower wheels in the rear - but they would run the exact same size tires both front and rear. The reason for this is to get more grip in the front by changing the shape of the sidewall of the tire with the wider wheels and in the rear get a nice progressive breakaway/rotation with the narowwer wheels. This made perfect sense to me.

Has anybody thought about or tried this? I imagine it would would perfect for the 205/50/15 Falkens on 7" wheels in the front and 6" wheels in the rear...

 

Yeah I read that too and I was thinking of doing this back 2 years ago. Since tire shape can change with the wheels you use. I know someone using 225 on a 7" wheel and the tires was all bowed and he complained of a sloppy handling car. Then went to a 7.5" wheel and the turn-in was much better.

 

Hrm... 225/45/15's on a 6" wheel?

Thats what i'm running for autocross. I figure its not as bad as trying this with a street tire due to the stiff-sidewall nature of an r-tire..

RJ