I'm a commuter with a ~13m daily round-trip. I've been riding this on an MTB for 8 years, but I'm looking to upgrade. I recently tried out a 2012 model Specialized Tricross; this having been recommended as a road bike that retains the commuter niceties (rack/mudguard mounts, etc) and can handle the light gravel tracks that form part of my route.
I love the bike, but I found one fundamental problem: The cantilever brakes set off this (initially) terrifying judder under pressure. On one downhill section, I couldn't brake enough to stop accelerating without this vibration running through the whole bike (and me), massively increasing my stopping distance. As a commuter in Oxford, being able to stop quickly and confidently is a must; something I've always been able to maintain with the V-brakes I'm used to.
Back at the shop I was told that the judder is something that all CX bikes share, and that it might have been accentuated by the fact I was on a fresh bike on wet roads. I've also read that softer shoes and toeing in can help reduce the level of vibration, but that nothing can be done to remove it completely.
So, can anyone point out a way to address this? Is it something I'd simply have to get used to, or have I just picked the wrong kind of bike for my needs?
Thanks to 'grivooga' at Reddit (via Cyclo), this is an ideal description of the issue:
What happened is that the fork blades and your headtube flexed. Just a little but enough to change the distance between the brake cable stop and the brake arms. This caused the brakes to pull harder. Something had to give, either the tire will skid, the brake pad will skip, or you'll go over the bars and crash. In this case the brake pad skipped on the rim. That released the pressure momentarily the frame and fork flexed back then the pad caught again and the process repeateded. The whole process happens very quickly, many times a second.
I'll try one of the recommended fork-mounted hangers, along with some better toe-in and maybe softer compound pads.
For future readers: After a couple of telephone discussions and a short wait, I took it out again with a fork-mounted hangar attached as shown:
The red circle shows roughly where the original hanger was situated. With the drop significantly reduced, all I feel now is the occasional soft vibration, and only when I lean fairly hard on the front brake. Enough of an improvement that I bought the bike.