I've already drilled out the back of the fork, so I'm good to go on the brakes. The reach on the 27" rim is ~60mm, so he tektros should be more than adequate. I don't have a 700cc wheel to measure the reach on, however, and my math skills aren't up to calculating the difference. Is there a formula I could use, or has someone else used one of these brakes on a 700cc?