Wednesday, December 9, 2009

Tuesday, December 8, 2009

Out out damned cantilever chatter!

Lennard Zinn had been teasing us for weeks now with his apparent solution for all time! -- to the dreaded and hated cantilever brake chatter that seems to be so common on cyclocross bikes these days.

Unfortunately the article doesn't go into quite as much depth as I'd like but it does confirm a few things for me-- namely that the brake pads were skip-slipping on the braking surface. Erk-erk-erk-erk! Some time ago Sheldon Brown had indicated that fork-crown mounted housing stops reduced or eliminated front cantilever brake chatter. And it's for the same reason that linear-pull brakes also don't suffer from the chattering.

A prime factor is the rigidity of the front end of the bike. Van Dessel discovered that forks with a tapered steerer (1.5" at bottom to 1.25" at top) vastly improved braking action. The larger crown race plus larger fork legs created a more rigid structure that resisted flex.

But what do you do if you have a convention bike? I sure as hell don't have the budget to go buy a new bike.

Well there are a few things you can do-- number one seems to be to run a linear-pull brake. You'll need to get a "Travel-Agent" adapter to enable use with your aero (or STI) brake lever or buy an aero brake lever designed to work with linear-pulls (Cane Creek and Dia-Compe both produce such a lever). Shorten the front brake pads-- this would entail cutting off the rear end of the brake pad as mush as possible. Apparently this is something the Richard Sachs CX team does.

Fortunately this is not something that's a problem for me. My LeMond still has its OEM Kenesis aluminum fork and I'm running Paul Neo-Retros. Under hard braking from speed I do experience some front-end shuddering but it's not "scary" or "dangerous" as some other riders have reported.

Go here to read the full article on VeloNews:
velonews.competitor.com/2009/12/cyclocross/technical-qa-with-lennard-zinn-return-to-cross_101807