38mm/1.5" is about the limit with 700C, and the inside faces of the chainstays are more or less parallel over the stretch from where the bulge of a 700C would be to where it would be on a 26" rim, so you're not going to fit much bigger tyres by shrinking the rims.
38mm/1.5" is about the limit with 700C, and the inside faces of the chainstays are more or less parallel over the stretch from where the bulge of a 700C would be to where it would be on a 26" rim, so you're not going to fit much bigger tyres by shrinking the rims.