I'm currently beginning an experiment with disc brakes. I'm building a 29er for a ride on the GDMBR this summer, and I'm using Avid BB7 mechanical discs. I read these forums daily and hear people championing this or that, and it gets me thinking. But I never fully believe until I try something for myself. I've been contemplating disc brakes for awhile. When I decided to try a 29er, I figured it was a good time to also try discs. I've previously had bikes with centerpull calipers, sidepull calipers, cantilevers, and V-brakes. Of those I like V-brakes the best, although my road bike has calipers and my tourer has cantilevers.

All my setups have worked fine, except when I had cantilevers on my old mountain bike. On long descents my hands would get so sore from pulling on the levers that I'd have to stop and shake some life back into them. The trend towards small, 2-finger levers didn't help. Ever try and buy brake levers that are long enough for 4 fingers? Good luck! V-brakes seem to offer enough mechanical advantage that this problem is mostly gone. I've ridden down some of the same descents that used to make my wrists burn, with no discomfort.

So now I'm going to try discs. There are couple of things I'm worrying about as the build progresses. One is that there seems to be less dish on the spoke (is that right? More or less? What I mean is the spokes have less angle coming out from the rims; they're closer to vertical) in order to make room for the disc, particularly in back. We all know that spokes are most likely to break on the drive side of the rear wheel because of less dish. I worry that I'll be even more prone to breaking spokes with the discs. This is a worry for me. I'm a big guy (200 lbs.) and I tend to carry a big load, and I've had issues with broken spokes before. I'm worried that the rough, bumpy, rutted surfaces on the GDMBR will make broken spokes more likely. Yes, I'll be using much bigger tires, but will this be enough?

The other I just read about in this month's ACA magazine. The guy, in an article on what to look for when buying a tourer, says that because discs are only on one side, they put twisting forces on the wheels that can contribute to wheel problems. Hmmm.

Anyway, after this summer I'll hopefully have some results of this experiment. Maybe I'll rave about discs, maybe I'll think they were a mistake, and maybe I'll say they're good but not that much better than V-brakes.