The Avid BB5 brakes get a bad rap, in my opinion. Yes, the BB7 are better because they have an easier alignment procedure, since both brake pads can be adjusted, whereas the BB5 have one pad fixed. But, that’s to my mind the only real advantage.
Change my mind.
Anyway. I have the BB5 on my trike front wheels, and I’m not inclined at this time to replace them. I will eventually, but that day is not today. With that in mind, I have to know how to align them so that they stop effectively and don’t rub on the rotors.
So I watched a bunch of videos on YouTube and read a bunch of bike repair articles, and have condensed what I’ve learned down to a quick-and-dirty alignment that takes all of five minutes and can even be done roadside if necessary.
You need a 5mm Allen key and a T20 Torx driver.
First, undo the two mounting bolts that hold the caliper to the frame, the two black ones in the pic below. Don’t remove them, just loosen them a couple of turns. You need to be able to wiggle the caliper.
Above and below the caliper, you’ll see a pair of thick washers. They are ball-and-cup washers, designed to compensate for the not-quite-perfect alignment of caliper mount and disc rotor.
Take the T20 driver and drive in (clockwise) the inner, adjustable, brake pad until it just contacts the rotor. Wiggle the caliper a bit to seat the ball-and-cup washers so that the brake pads are parallel to the rotor. Then, drive the inner pad in a few clicks more. You’re going to put some pressure on the rotor using that inner pad to create an air gap between the outer non-adjustable pad.
Now, alternately drive in the mounting bolts. Don’t drive one in all the way then jump to the other; the uneven pressure will cause the caliper to skew out of alignment. Once both are tight, drive out (counterclockwise) the inner brake pad until it is clear of the rotor, and spin the wheel to check there’s no brake rub. You might need to quickly squeeze and release the brake lever once. If there is, loosen the mounting bolts and start again.
Once you’re satisfied there’s no brake rub, and your mounting bolts are tight, set your brake lever to about half-pull. Not all the way to the grip, but with a half-inch (1-1.5 cm) gap. For locking brake levers, set the brake lock pin. Drive the inner pad in just until tight plus one click.
The reason for the half-pull is that you want to leave a little play, for two reasons. One, it allows for brake modulation; you have room to really pull hard on the brakes to stop fast if necessary. Two, cables stretch, and this gives you some small amount of wear before you need to take up that stretch with the caliper and lever adjustment nuts.
And, you’re done!
Tastes Like Tofu 