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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 04-20-12, 09:51 PM   #1
uspspro
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Reminder: Avid BB7 Caliper Maintenance

So I bought some replacement plastic adjuster pieces to replace the old melted ones, and also got some new stainless steel mounting bolts with positioning system (as opposed to the standard black coated ones).

Plastic pieces: http://www.universalcycles.com/shopp...10&category=20
SS Mounting bolts/system: http://www.universalcycles.com/shopp...30&category=20

I've never had a BB7 caliper fully disassembled. So tonight I took the whole thing apart to see (1) exactly how it works and (2) if anything could use maintenance.

Inside the mechanisms are pretty simple. There are 3 ball bearings that ride up/down tapered ramps to push the piston in/out, a spring to load of the arm, etc.

Inside everything was caked in brake dust, so I cleaned everything (including the bearings and ramps and lubed them lightly with pro-link oil. I did not use grease, since I wouldn't want it getting out and on to the pads/rotor, and because there was not grease on there before.

Also, there is a nut behind the outboard pad adjustment knob that holds the arm onto the piston. Mine was not loose, but there was not very much torque on it. I tightened it a bit more than it was.

Afterward, the arm actuation seemed smoother with the clean bearings/surfaces and with less lateral play.

Just something to think about doing every year or so.


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Old 04-21-12, 05:52 AM   #2
PMK
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Agree, the arm retention nut on all of our tandems has been less than secure. I found that tightening the nut with a slight load applied to the brakes ensured the arm was seated in the correct position.

This tandem group is often a by the book group. So to keep the engineers content, this is the official, current revision for this date, set of manuals for the brakes. Not only is overhaul located here, but also replacing the brake pads and pad break in procedures.

http://cdn.sram.com/cdn/farfuture/bN...l_bb7__bb5.pdf

We have very good results with our BB7m brakes. One concern that has happened with ours is that over time the caliper position can creep in the spherical mounts. Nothing bad or dangerous, just minor brake rub. Last night while making some changes to the bike, I installed billet brake caliper adapters, and omitted the under fastener head spherical seats. I attempted to run just spacers but did not have spacers of the proper outside diameter. Not ridden it yet, but the brakes have a more solid feel, similar to freshly bled brakes on a motorcycle with degassed fluid.

This link is from when I found the actuator arm working loose on the off-road tandem.

http://forums.mtbr.com/tandem-mounta...7s-694084.html

PK

Last edited by PMK; 04-21-12 at 06:01 AM.
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Old 04-21-12, 06:55 AM   #3
rdtompki
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This is a very timely thread. We have 8000 miles on our tandem (rear disc) and my single has two BB7. Now that I'm running a Shimano ICE rotor my LBS suggested I might adjust the alignment frequently to minimize rotor deflection. It's an easy procedure and I'm going to do it this weekend. The disassembly and clearning also sounds very, very worthwhile. Another tip I got from Bryon at Crank-2 is to use a torx T-25 to adjust the inner pad. That inside adjuster is a real pain.

I'll order some spare parts this weekend. Thanks!
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Old 04-21-12, 07:33 AM   #4
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Quote:
Originally Posted by rdtompki View Post
This is a very timely thread. We have 8000 miles on our tandem (rear disc) and my single has two BB7. Now that I'm running a Shimano ICE rotor my LBS suggested I might adjust the alignment frequently to minimize rotor deflection. It's an easy procedure and I'm going to do it this weekend. The disassembly and clearning also sounds very, very worthwhile. Another tip I got from Bryon at Crank-2 is to use a torx T-25 to adjust the inner pad. That inside adjuster is a real pain.

I'll order some spare parts this weekend. Thanks!
FWIW, if you lubricate the threads on the inboard adjuster, normally you won't need the wrench. Also, FWIW, the Torx wrench is supplied by Avid with the brake kits. We carry one in the tools on all the tandems.

PK
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Old 04-30-12, 09:21 AM   #5
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Did the first long ride yesterday with the ICE rotor. Stopping is uneventful and I clearly have more brake available at lower brake lever pressure. Pulling into the rest stop after the only big descent I did experience quite a screech from the rotor, but I'm attributing that to things bedding in; I'll clean the rotor tonight. Adjusting the BB7 mounts no doubt helped, but I see a significant improvement over the steel Avid rotor. I may even consider trying a pair of these on the Volagi, although the stock setup does seem to work very well.
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Old 04-30-12, 12:18 PM   #6
twocicle
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Not a lot of mileage on ours yet, just a couple short rides. Stock BB7 components (incl pads) + ICE rotor is working very well w/o excessive noise, albeit no killer descents yet...


Last edited by twocicle; 04-30-12 at 12:21 PM.
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