Ok, BIG problem. This afternoon I went installing the tyres, but the guy at the shop wasn't able to install the 130 mm tyre I ordered. Turns out the rear rim (which is an aluminium cast, made in the '70 by OZ) is for a 500 four, not 750.
Now I put on a 3.50 tyre (110 mm), the original size for a 500, how about racing with it? Or is it too dangerous?