I just bought a set today and they told me they were 2.05x12 rear and 1.85x12 front. May be something different but they were listed as Pitster Motard wheels? If they turn out to be 2.15 in the rear I'll just be that much happier
I am definately not an expert but I've been researching this rim and tire thing for a few weeks now and I think your setup should be perfect for either one of those sets of tires. I believe the widest rim made in 12" is 2.5 by cyclone (but only in 36 spoke version) at least that's what I heard. Someone feel free to correct me if I'm wrong?