13 inch is the diameter to the outside edge of the wheel.
It's the smallest inside diameter that you need to be sure about. The discs are 260mm which is around 10 inches then you would obviously need a bit if wiggle room around this as well just in case of emergencies.
It could be a close call, possible get a hold of a cheap wheel or borrow one to make sure.
Why 13 inch wheels anyway, looks wise 15's is about the smallest I think you should go and helps with tire price, 13's are just too small, even with a 60 profile tire you would struggle to make them look right under the wheel fender.
Started 22/6/11 Finished 13/8/12 487 Hours Build time. Now on the road, weather dependant.
If you can get the 13" wheels to fit then that's going to lose a big chunk of unsprung weight and give a better choice of tyres so definitely worth doing if it's going to spend a lot of time on race tracks. But for the road I would use 15" as Iv'e not yet seen a guard that looks neat on a 13" tyre. I'm planning to have mine quite track bias so will be looking into using 13"s, I'm using Hispec uprights with 280mm discs and don't really want to go any smaller on the disc size.
Can anyone tell me the rolling size for the tires? I just need something in the ballpark
you could use the Power of Maths! 13" is about 330mm diameter, plus the profile of the sidewall, lets say you've got 55/165/13 tyres, that's 55% of 165 = 90.7mm. Gives you a radius from centre of the hub to edge of the tyre of ~210mm.