Tandem Cycling - Avid BB7 Pad Wear Adjustment

I moved the post, below, over from Bicycle Mechanics since there is a good deal of disc discussion on this forum. I should add that the reason I need to adjust for pad wear after only 900 miles is the incredible squeal from my front v-brake which causes me to overuse the disc. My wife/stoker has threatened to ground us until it's fixed. While I'm working the squeal problem my chances of finding a hot, young, hard-of-hearing stoker are greater than those of fixing the squeal.

Avid BB7 post follows:

"I've looked at both the Avid and Park Tool instructions. Everything makes perfect sense except the adjustment for pad wear. The instructions say to set up the gap to be 2X on the inner (fixed) pad. Once the pads have worn the Park Tool instructions direct the reader to turn the inner adjustment knob 2 clicks for every click on the outer. If the inner and outer pads wear equally I would expect an equal number of clicks on the two knobs to restore the original pad gaps. Am I missing something?"

Here's a photo someone took of the outer (LEFT) and inner (RIGHT) adjument knobs from an Avid BB7 caliper, albeit an older model and both knobs were painted black (the things people do). Anyway, if you look at the two knobs I think you'll figure out why it takes two 'clicks' on the inner and only one 'click' on the outer.

http://farm3.static.flickr.com/2123/2423795361_776c655d8a_o.jpg

Here's a photo someone took of the outer (right) and inner (left) adjument knobs from an Avid BB7 caliper, albeit an older model and both knobs were painted black (the things people do). Anyway, if you look at the two knobs I think you'll figure out why it takes two 'clicks' on the inner and only one 'click' on the outer.

http://farm3.static.flickr.com/2123/2423795361_776c655d8a_o.jpg

TandemGeek, FWIW, the small knob is outboard while the large knob is inboard nearest the spokes. No big deal.

I read this late last night and have no idea why they say two for on clicks. Normally, I set the outer to just lightly touch a spinning disc, then come out a click or two. I bring the inner pad to the point where the lever travel is good.

PK

TandemGeek, FWIW, the small knob is outboard while the large knob is inboard nearest the spokes. No big deal.

Dyslexia sucks... Thanks for pointing out my mental mis-fire and it's now FIXED.

As for the 1 vs. 2 clicks, I suspect because it's a reasonable way to ensure whoever is reading the instructions is adjusting both pads (not just one) and moving them in to what amounts to about an equal distance at each adjustment interval. If you don't adjust the inner pad you will eventually find the rotor rubbing on the caliper body (metal on metal) and that's a bad thing.

As it turns out after only 900 miles my pads are at the 3mm wear limit. I'll have to round up some new pads tomorrow. Does anyone happen to know the dimension of the pads when new? I'd be interested in how much material I wore off in these few miles.

The 3 mm guideline includes the metal holder.

Understand the 3mm includes the holder. I don't have micrometer, but I'm certainly below 3.5mm. I have no slack in the cable and even when I adjust the pads correctly I have way too much brake lever travel and no stopping power. We are probably 390 lbs including loaded bike and while we don't do long, technical descents there is little truly flat around here. Still, I'm surprised we could have worn the pads out so quickly.

Still, I'm surprised we could have worn the pads out so quickly.

Your pad wear sounds better than what we were getting with Avid organic pads....about 500miles. I switched to the Avid metal pads with the vented Hope rotor and have not had to make an adjustment in 250 plus miles. We do most of our riding in the south bay and while not in the USPSpro category most rides will include a hill or two.

We did Hassler Pkwy* (after climbing Metcalf) in San Jose Monday on the tandem, I did it last night on the single I thought the tandem braked as well or better than the single.

*Hassler Pkwy in San Jose is a 7.25% grade over .92 miles that ends at a T intersection.

After buying a new set of pads and seeing how thin the material is to start with I'm convinced my pads are not worn to uselessness, but need proper adjustment. I'm going to work on this tonight. I hadn't adjusted the pads in 900 miles and the braking went from good to non-existent probably based on running out of brake lever travel.