thanks guys.

I run 225 50 R 14 at 22.8 OD, 9 inch width KUMHO which are a bit wider than Hoosier

225 50 R15 would be 23.7 OD sames width.

At RA I run the 4.73 gears. Now I know I could go back to 4.11 which would change the rev pattern and that is an option for next year.

I ran 2.50 on Saturday, did not try and go fast on Sunday as it was my last race this season anyway and I was not running enough to challenge anyone in points. I think i could have run about 2:49 or a bit better with what I have. I run 650's in the back springs and my motor is good, but has no piggyback just a 6 year old chip at this point. In going through the carousel and Kink I would like to up my speed there and I have been pretty conservative there so I know I have time to make. My thinking with more OD, I would have less revs so be in a better power band to go into Canada and also pick up some advantages. Right now I do about 7000 into 1, 7000 into 5, but best into 12 was about 6700 on Saturday and maybe 6300 on Sunday.

So I think what you are telling me is it possible; we fixed the rub on the Kumho 14's early on; The 15 inch wheels I think are good at about 11 lbs are 35mm offset (miata). Bigger tires weigh more, but wheels keep total unspring weight gain to a minimum.

If I want to run with Midwest Council in the top three I have to be 2:48 and we did see 2:47 and even faster this year with a couple of national miata guys.

Further thoughts?