I ran a set of BB7s on my bike without problems and they worked fantastically well. I upgraded to hydraulics recently and rather than leave the BB7s lying around I decided to turn my old bike into a more commuter orientated machine and fit the BB7s. Everything went well, rigid forks fitted, bb7s fitted and adjusted etc. I applied the brakes again just before finishing and the front BB7 locked solid and the lever wouldn’t return, I couldn’t work out what was going on, after all the brake had worked well on my other bike and I’d just fitted it to a 2 second bike. On closer inspection it turns out that the cable retention clamp on the brake arm is wedging itself against the head of a bolt that fixes the caliper halves together when the brake arm is pulled up. There’s masses of clearance between the two on the rear caliper (and afaik the calipers should be the same, it’s just the adapters that differ). The caliper that’s jamming has worked without issue on another bike; I can’t work out what’s happened. Could there be some internal wear that’s causing the arm to move in towards the caliper body.

The picture below isn’t great but you might be able to work out what’s going on. Like I’ve said there’s no clearance issue on the rear caliper and this jamming unit was working fine before. With the cable in place the retention clamp is pushed out somewhat but even with now cable fitted there’s virtually no clearance as the brake arm moves up. The bolt the arm’s wedging against isn’t loose. Any help would be appreciated as I’m flumuxed! On the rear caliper the arm is much further outboard as it passes the caliper itself.

Difficult to say without seeing it in the flesh, but wouldn’t altering the pad position using the adjusters then allow the leverarm/clamp arrangement to sit in a different position where it won’t foul?

Sorry, it’s not a great picture, basically the edge of the cable clamp is wedging itself against the head of the allen bolt (which isn’t loose and protruding) and locking the brake. It bizarre as the whole setup worked fine on the previous bike! I’ll play with pad positioning but the rotor is pretty much where it should be relative to the caliper and I think (but could be wrong) that the arm/caliper distance is fixed, I think the pads move independantly.

I’ve got another BB7 caliper from a 160mm setup (current is 185) which I could just fix on the 185mm adapter if I can’t sort this one out.

I had a look at my BB7s this morning. Sadly mine are the earlier (grey) design, and the cable clamp couldn’t reach the caliper unless the brake arm was shorter. So it seems like this will be specific to the 08 design?

All I can suggest is that the cable looks from the photo to be too close to the bolt. Is there a groove in the clamp for the cable to sit under which would allow the clamp to sit more flush to the side of the brake arm. If the cable is pushing the clamp up, it might be that the bolt feels tight but the clamp is being lifted by the cable. It looks to be like the cable should be exiting further inboard. Worth a try?

I’ve got a front BB7 in the 08 design – I’ll take a look at lunchtime.

I’ll certainly fiddle with the cable position, that’s got to be worth a try although even with the cable removed clearance is tight. I can’t work out why, after a lot of use, it’s suddenly started catching; the move to the old bike might be coincidental. I’ve got a spare caliper somewhere too so I’ll have a look at that.

why not just cut the metal cable clamper down a bit?

I’ve checked BB7 on my Kona PJay – there’s about 3mm of space between the cable clamp and the body of the brake. It’s as though the arm’s moved ‘inwards’ from your image / description.

I’ve got the older BB7s but i can see your problem. Have you set up the caliper so that the pads are dialled all the way out and the slack is taken up with the barrel adjuster on the brake lever? I’m just wondering if you can get the pads to bite the rotor before the cable clamp even reaches that bolt. If this is the case then you should be setting up the caliper using the avid video on youtube
You shouldn’t be using the barrel adjuster to take up too much cable slack – the way to get an early biting point on the lever is to use the pad contact adjusters (per video).

If this isnt the issue, you could just do what alexxx says. take off the clamp, put it in a vice and file it down. after all that bit of the clamp dosen’t actually do much. or if you’ve got an old mech with a smaller clamp on it you could try swapping them over. you could also try filing down the edge of the bolt – as long as you don’t take off too much its not going to compromise things too much.

Hope that hepls

The arm does seem to have moved inwards, on an older caliper there’s much more clearance. I’ve dismantled the arm and there’s just a big return spring inside which I’ll try and stretch a bit as the arm seems to need pushing outwards.

Well, a bit of an update for those interested. I seem to have figured out what’s going but I’m not entirely sure why, or how to fix it.

I’ve dismantled the arm which turns out to be a fairly simple set up. There’s a hexagonal spindle over which the brake arm sits and a big return spring. There’s also an hexagonal washer which sits over the spindle and rests on a lip on the spindle, it spaces the arm on the spindle and I assume that it’s steel and there to resist wear. This lip, on this particular caliper, doesn’t seem exactly square and appears slightly lower on one side, the effect of this seems to be that when the brake arm is bolted down it rests on a slightly angled washer causing it to tilt in towards the caliper body enough to hit the bolt when in action.

I don’t know whether this was caused by a tolerance error during manufacture or wear (I’m a chunky chap and it’s a bigger 185mm rotor although I can’t quite seem how this would affect things); it’s a pretty new setup. The piston material (and spindle) does seem rather lightweight and ‘soft’ (I’ve lost the nipples on the pistons on a couple of calipers), presumable to keep weight down.

I could probably heath robinson something with other washers but I’m not sure I’d trust myself with something like a front brake!