Originally Posted by
TandemGeek
Hmmm. I'm guessing the problem is with his front brake, moreso than the disc. In the wet, the rear discs typically have more 'bite' than the rear wheel has traction to use it and you simply skid the rear wheel.
Regardless, I'd suggest having him check the "freshness date" on his brake blocks (if they're old, consider new ones with more bite), do the brake track cleaning think, and also check rear disc for proper adjustment, pad wear, and proper rotor centering per Avid's instructions.
Those are good suggestions. I'll pass them along. He's also going to replace cable and housing. Never hurts.
When I brake in the wet, it always takes maybe 40' for the rim brakes to start really grabbing, so it's important to start braking much earlier than we do in the dry. He may have just waited until too late. One of the things I noticed with the alcohol is that this distance seems to be less. He said the disc "didn't do anything." But they finished the ride fine, so it must do something.