Originally Posted by PapoZalsa

Even that you said that you tried, the best thing is to use a tire calculator online. That way your speedo won't be too much off. The other way would be to see if you find someone that have switch to a different size of tire and see if you like it.

Most of the time once you change the OEM tires sizes the speedo will have a very small % off.

Anyway, how wide are the base rims?