[Aussie Mike]

I'm running 315/35/17 Sumitomos on the rear 17"x11" rims. Since there isn't much sidewall you need a wider rim as they pull in on a smaller rim. I've seen them installed on 10" rims and they look OK but are starting to pull in.

Tyre widths are measured from side wall to side wall and since the 315 has basically straight sidewalls with little or no bulge this translates to a fairly huge tread contact patch.

The fronts are 235/45/17 on 17"x8" rims. They are both similar rolling diameters and whilst they don't fill up the guards like a 15" tyre you can always lower the suspension a bit to get that look.

They may not be the stickiest tyre available but they are great value for money and will probably hang on better than any 15" tyre apart from race compound tyres.

My theory is they will do fine for the street and I'll keep a set of dedicated race rubber for the track. It's only about $80 to get them swapped over at my local tyre shop. I plan to buy a spare set of rims eventually though.

Initially I was thinking about using race rubber for the street but from talking to people who have used them, race rubber on the street is just dangerous. They don't seem to work till they get warm and they only have a limited number of heat cycles till they are stuffed.