I'm using 26" Schwalbe Marathon Plus 2.0 width on my converted mountian bike and they've been great. I run them at the maximum recommended psi when running on pavement and 40psi when on gravel and off pavement. They feel really squirelly on pavement at 40 psi, but fine at max psi. The've been wearing great. The 35 width Schwalbe Marathons on my 700c bike haven't lasted near as long.