I have schwalbe Marathon Duremes in both 26" and 700cc, great tires. They are awesome on the road and handle gravel and light off roading well. I also haven't had a flat on my 26" tires and I put them on in early April with plenty of miles since. I just got the 700cc bike but I would assume the same perfromance. I have road the 700x 35 on gravel a few times though and they were great.