Avid BB5 or BB7 Disc Brakes?

[teethgrinder]

with BB5 and BB7 the FPA needs to be maintained so that it doesn't seize up(it will corrode in a UK winter...). With any mechanical disc brake caliper it is necessary to strip and overhaul the workings from time to time. With BB5 and BB7 calipers this is easy enough, there are only four (4) ball bearings inside, and normal service is soon resumed.

With spyke/spyre brakes there are about forty tiny ball bearings inside (because they have a needlessly complicated thrust bearing arrangement), no seals of any kind, and normally by the time the caliper is opened up (which is far from easy) it is too late anyway, they are usually f***ed.

cheers

Fair do's.
The closest I got to stripping a BB7 was having a go at my much neglected BB7s from my hybrid. Anything with moving parts needs maintenance. I let mine get so corroded that I was rounding T bits etc trying to get things undone and the whole unit was so badly corroded I didn't think it was worth the hassle.
Never had any problems with my Spyres after running 3 bikes on them for an average of over 20,000 miles each. I'd say they faired better than the 3 BB7s after a similar mileage.
I've yet to try and strip down a Spyre. Sounds like from a mechanics point of view BB7s are best. Though it was a pro mechanic who put me on to Spyres, they were only intended to last a year.
Purely from my experience so far, I prefer my Spyres but BB7s are still very good. They aren't a great hardship to adjust, just that I found the Spyres much easier. I still have some BB7s and I won't be binning them!

[zigzag]

Purely from my experience so far, I prefer my Spyres but BB7s are still very good. They aren't a great hardship to adjust, just that I found the Spyres much easier. I still have some BB7s and I won't be binning them!

iirc, on the first 1ytt i saw bb7mtn calipers with sora road levers on your bike - just curious if that was intentional for some reason or a case of using what you've had available back then?

[teethgrinder]

iirc, on the first 1ytt i saw bb7mtn calipers with sora road levers on your bike - just curious if that was intentional for some reason or a case of using what you've had available back then?

They were ordered in haste  . The only apparent difference was the mount but I just mounted the caliper onto the mounts (BB5) that were already on the bike.

[Mrs Pingu]

Hope the OP doesn't mind a little thread hijack...

My BB7 MTNs are getting a bit sad after 5 Aberdeen winters and no TLC. I see there is an internals replacement kit in theory, but they're like hens teeth. Could get a set from Germany but I really object to paying 15 Euros for the postage. Anyone know where else I could get this kit, or shall I just spring £45 for 2 new calipers off the bay of e?

[Torslanda]

Just checked the Zyro website. A full set of internals for one caliper will cost you £31.

Back ordered, 6-8 weeks lead time...

There's a 'pad adjuster knob kit' in stock which is 8 quid.

[Mrs Pingu]

Just checked the Zyro website. A full set of internals for one caliper will cost you £31.

Back ordered, 6-8 weeks lead time...

There's a 'pad adjuster knob kit' in stock which is 8 quid.

Oh ta. So can J Random Punter order off there? (Just looked and failed to find) or is it retailer only? Having said that if i can buy 2 calipers for 45 squids why bother.
Answered my own question, thanks

[Gus]

Just remembered I found 2 videos on youtube, on how to clean the BB7, and thus improve performance again :

https://youtu.be/rppADOgTNSM

https://youtu.be/hEsa-iWakdc

[Mrs Pingu]

 

[Brucey]

FWIW a rebuild kit for a mechanical caliper may not include the ramps that are press-fitted in the caliper body, or if it does they may not be easy to replace.  These parts and the moving parts can wear/corrode but IME it is rare that it is so bad that the caliper misbehaves; normally new balls is enough in a BB5 or a BB7.

There are a couple of twists that are worth knowing about

1) the foot that the moving pad bears against is located by a snap ring in some caliper designs; this allows a little articulation of the moving pad. In some cases it is useful to reset the foot to one side as far as it will go so that the movement doesn't allow the pad to contact the disc when you don't want it to; the pad springs don't always push the pads back perfectly square and this can make a difference.

2) The caliper body can wear. The caliper piston is (when applying the brake at a standstill) normally supported by the ramp balls and the pad thrust; the shaft doesn't make contact with the caliper body and the OD of the piston doesn't either, (despite the offset force arising from the cable, which is higher in a 'road' caliper BTW). However when the brake is applied on the  move, the pads move in the direction of disc travel and contact the caliper body, and sometimes the piston moves in a similar way too.

  It isn't unusual to see some wear marks inside the caliper body from both these things.  However I have seen some calipers in which the piston has worn the bore far more than the pad backings have. I think this can occur if the caliper arm doesn't return fully; this is inevitable with BB5 (because of the way it adjusts) and it may allow one of the balls to go out of position or something. A full arm return better resets the balls.

BTW apologies  if this is obvious but whatever grease is on the balls ends up being mixed with pad wear debris, so becomes an abrasive slurry, and even if it is still coating the wearing parts they should be cleaned and regreased.

My suggestion is that you clean and regrease the ramps and balls (using a high-solids, high melting point grease (not copper ease) and that the FPA threads are treated with a little anti-seize, and see how you go with that. New balls if necessary of course.

With BB7 you can split the caliper and this allows you to dismantle most of the caliper without disturbing the FPA knob. With BB5 you have to remove the FPA knob  because the caliper body is one-piece.

cheers

[Kim]

With BB7 you can split the caliper and this allows you to dismantle most of the caliper without disturbing the FPA knob.

Yes, but that doesn't matter, because the thing that's most in need of regular maintenance to prevent it seizing up on a BB7 is the FPA mechanism.

[Brucey]

I was trying to make a distinction between the FPA knob and the FPA threaded piece itself. IIRC you can wind the latter in and out of one half of the caliper body without disturbing the knob itself, which can suffer broken fingers during removal.

cheers

[Kim]

I was trying to make a distinction between the FPA knob and the FPA threaded piece itself. IIRC you can wind the latter in and out of one half of the caliper body without disturbing the knob itself, which can suffer broken fingers during removal.

Ah, fair enough.  Yes, you can.