BB7 brake issue I think

[Brucey]

the foot is pretty soft and often it is difficult to refit it without jamming/mangling the clip/ring. I've never seen one as bad as Mikeymo's though.

The problem seems to occur because the ring hangs out the side of the groove in the foot, like this BB5 one;



It can be difficult to refit the foot unless the ring is squeezed inwards as it is fitted.

The good news is that (certainly in BB5, maybe in BB7) you can strip the mechanism to overhaul the ramps etc without pulling the foot from the 'piston'.

The free tilt comes from slack between the sides of the groove and the ring; it always gets more as the caliper gets older.

cheers

[Mike_Ayling]

I think I will stick to V brakes!

Mike

[mikeymo]

I think I will stick to V brakes!

Mike

Depends what sort of bike/riding/conditions you're doing.

I put BB7s on a Ridgeback touring bike I built up, which is almost exactly the same (at least geometry, weight etc.) as another Ridgeback tourer I've got with cantilevers on. I spent a lot of time setting up the cantilevers, which were very poor at first, including putting Koolstop salmon pads on them. I made them considerably better, to the point that they're 'not bad' now. And I would still use them for steady touring.

But the discs are better, especially in the rain. And if a car pulled out in front of me I would have a far better chance with the discs than the cantis, I think.

Don't let the pictures of the BB7s put you off. They're relatively simple, and like any aspect of the mechanics of a bike, once you understand it you can understand it COMPLETELY, that's the great thing about a push bike (unlike modern cars, for instance).

It took me a while to set them up, and I might have caused that damage myself, but that's part of the learning process.

[reohn2]

YouTube is loaded with videos on BB7 how to strip,maintain and adjust them.
These brakes aren't rocket science to work with if people wish to just take a leettle time out to learn .

[mikeymo]

YouTube is loaded with videos on BB7 how to strip,maintain and adjust them.
These brakes aren't rocket science to work with if people wish to just take a leettle time out to learn .

He's right. I've also spent time setting up cantilever brakes, which needs about five arms to do it properly. After which, with expensive new brake shoes, you've got brakes which are sort of OK. Until it rains. Compared to them BB7s are a doddle. And better, as brakes.

[jb]

As above - not rocket science - first check the rotor is not wobbling by any noticeable amount
take out the pads and check over heating hasn't softened spring
Replace, and adjust the static pad so when it touches the rotor the rotor is in the middle
Tighten the moving pad until it clamps the caliper onto the rotor.
Tighten the caliper screws.
Back off both pads until it stops rubbing.
Adjust the cable length so the brake arm moves immediately with the lever, ie no cable slack.
They should work for a good few rides before needing adjustment again.depending on how hilly it is around you.

[jb]

All disc brake pads on cycles suffer from uneven wear which is why they should be changed when seemingly only half worn.
On car brakes the rotor is so rigid it helps keep the wear even.

[Brucey]

All disc brake pads on cycles suffer from uneven wear which is why they should be changed when seemingly only half worn.
On car brakes the rotor is so rigid it helps keep the wear even.

indeed. And since (amongst other things) bicycle brake pads often have springs between them, you cannot wear the pads down very far without causing problems. If you read the manual for most bicycle brakes, the wear allowance (on brake pads with ~2.4mm of friction material) is actually a little over 1mm or so. 'Half worn' is the maximum that the manufacturers permit.

cheers

[reohn2]

I've just week before last changed the pads in a rear BB7 caliper on my MTB,they were about <2mm thick and worn evenly.

[mikeymo]

the foot is pretty soft and often it is difficult to refit it without jamming/mangling the clip/ring. I've never seen one as bad as Mikeymo's though.

The problem seems to occur because the ring hangs out the side of the groove in the foot, like this BB5 one;



It can be difficult to refit the foot unless the ring is squeezed inwards as it is fitted.

The good news is that (certainly in BB5, maybe in BB7) you can strip the mechanism to overhaul the ramps etc without pulling the foot from the 'piston'.

The free tilt comes from slack between the sides of the groove and the ring; it always gets more as the caliper gets older.

cheers

Resurrecting old thread:

Brucey

I'm about to check/grease/prep the bike before summer. And was thinking of replacing that BB7 foot. But the small parts kit is £30, whereas all I want is the foot.

In your experience do you think foot should be OK? The brakes feel fine after I finally fitted them and adjusted them. And I did manage to make the ring circular again. Just considering safety, obviously.


At the moment Spa are actually doing a whole brake for £45 which makes the £30 for the repair kit seem a bit daft. As I'd get an actual caliper, rotor and pads for the extra £15.

[Brucey]

I wouldn't worry overly about that damage causing a catastrophic failure. Maybe use that part in the rear brake rather than the front?

cheers

[reohn2]

It will be OK if you've straightened out the 'c'clip and it's seated in the groove and if any burrs or roughness has been smoothed off the shaft of the foot

[mikeymo]

Thanks folks. Yes, I straightened the circular clip with a bit of dual needle-nosed plier work. Then quite a bit of cursing to get it back into the groove, then a bit more fiddling to get it back into the actual caliper body.

Thinking about it, there's no actual in/out movement going on during braking is there? In the sense that the foot is static inside the caliper. It's the caliper that moves in and out. So the only tiny bit of movement is during adjustment. So no real danger of anything much.

Like Brucey says, maybe move it to the back.

Though at £45 I might get a new brake anyway, cause I'm sometimes a bit OCD and I'll get a spare pair of pads and a rotor.

[Brucey]

Thinking about it, there's no actual in/out movement going on during braking is there?

of course there is

cheers

[mikeymo]

Thinking about it, there's no actual in/out movement going on during braking is there?

of course there is

cheers

I am thinking about in/out movement between the foot and the caliper it inserts into. Are you saying that during braking, the foot moves into (or out of?) the caliper?