Avid BB5 Disc Brakes - help/advice needed

[lejogger]

Hi,

I've had a Boardman CX for 6 months (over 2,000 miles), and one area where I'm not totally satisfied is the brakes... Last year, one of my colleagues bought the Bman Hybrid Comp 2010 with the same brakes, however I believe that these are the black MTB version rather than the silver road ones. What I've noticed though, is that the stopping power between the two is massively different, and I don't understand why this would be.

I've had to get them adjusted at least 3 times because after a while the lever becomes so loose that my gear changer is wedging on the bars because I have to squeeze so hard to stop. Is this normal? My colleague hasn't done anywhere near the same sort of mileage as me, but has required no adjustment.

At present, the lever still feels pretty taught, but the stopping power is totally diminished, to the point where if it's damp and I'm on a descent I'm really throttling the things... specifically the front brake. Could this be that the pads are done? After only 2,000 miles? It's not something I want to be worrying about all through the winter.

So does anyone have any specific advice? Essentially, the questions are:
Is this amount of problems normal for the BB5 Road?
Does it sound like I need new pads?
Should I forget the pads and just upgrade to the BB7?

Apologies for the long waffly post!

 

[Globalti]

I bought a Tricross disc last month and the first thing I did was to swop the BB5s for BB7s, not because I'd heard bad things about the 5s but because the 7s are adjustable from both sides and I thought it would be better to have them. I have some experience of hydraulic disc brakes but almost none of cable discs, so far. I do know that the black BB brakes are supposed to be for mountain bikes while the silver ones are for road bikes, the difference apparently is in the pull ratios of the actuator levers, which suit either road brake or MTB brake levers. I don't know if the difference is in the length of the actuating levers or the arc of operation or the gradient of the thread.

With the little knowledge I have of these brakes it sounds as if your pads may simply be worn out. In what conditions have you been riding? Flattish? Hilly? Road? Off road? Do you know how to remove the pads? It isn't difficult - I guess they shouldn't have less than about 0.5mm of material left.

 

[steve52]

cable stretch? not just adjusting on the adjusters , i may be teaching u to suck eggs but ya never know ,i have the same bike and have no probs

 

[RecordAceFromNew]

Avid says BBx pads should be replaced when the total thickness falls below 3mm, meaning pad falls below approx 1mm.

I bought two brand new sets of BB7s including rotors from some shop in Hongkong on ebay for £60 recently - make BB5 pads look expensive...

 

[GrumpyGregry]

BB's, he said peering at the pair on the floor under my desk, are very setup sensitive on drop bar bikes, whilst being merely choosy on MTB's. Everything has to be just so, and to get it just so, if it isn't out of the shop door, usually means new inners and outers. This, I think, is the definitive setup guide. I'd recommend Avid Full Metal Jackets to you whilst the underdesk ones (it''s for a long term project where everything has to be second hand) are goodrich.

But ime, first step is to replace the BB5's with BB7's just for ease of adjustment out on the road.

 

[lejogger]

With the little knowledge I have of these brakes it sounds as if your pads may simply be worn out. In what conditions have you been riding? Flattish? Hilly? Road? Off road? Do you know how to remove the pads? It isn't difficult - I guess they shouldn't have less than about 0.5mm of material left.

Cheers for your reply. I've been riding on roads only, and both hilly and flat terrain... use it as commuter, tourer, winter club bike etc so it's seen everything tarmac related. I guess my commute can be very stop/start at times.
I haven't fiddled about with them too much to be honest because I'm new to discs and I worry about tampering with things that ideally need to stop me. I'm sure I can google a user guide for removing the pads so that I can check the pad wear.

 

[lejogger]

cable stretch? not just adjusting on the adjusters , i may be teaching u to suck eggs but ya never know ,i have the same bike and have no probs

I don't think it's cable stretch this time... it was previously, causing the levers to get so loose, but this time I don't have to squeeze so hard to feel contact with the disc, it just doesn't feel like the pad is gripping the disc as well as it did... if you get me?

 

[lejogger]

Avid says BBx pads should be replaced when the total thickness falls below 3mm, meaning pad falls below approx 1mm.

I bought two brand new sets of BB7s including rotors from some shop in Hongkong on ebay for £60 recently - make BB5 pads look expensive...

Might be worth a look then if better quality, easier to set up, and better stopping power?

 

[potsy]

I'm just over a week into my BB5's and am impressed with the stopping power compared to the calipers on my road bike.
I am though expecting to have to learn how to adjust them regularly, to keep them in good order.
Will give them a chance before upgrading to the BB7's.

 

[byegad]

For BB5s 2000 miles could well mean the pads are shot, I wore some out in 1000 miles! Do yourself a massive favour and take the opportunity to change to BB7s, they are a much better brake and come in both road and MTB versions, you need the version which suits your brake levers.

BB7s are easier to keep in adjustment and have a larger pad so stop better than the BB5s for a given hand pressure. Chain reaction were selling BB7s at £55 a while back and may still be doing so. At least change the front one. Changing over is just a case removing the BB5 calliper and replacing with the B7 calliper the discs are the same, so you'll gain a spare disc!

 

[ufkacbln]

Both these brakes are sensitive to setup and require good cables.

On my Gekko the BB5s were appallingly poor, so I swapped to BB7s and had the same issue.

Then removed the two flexible armoured bends from the cable run and fitted Nokon cables. Instant revelation and imacculate stopping power!

Good stiff cables and a direct run will certainly improve these brakes

 

[GrumpyGregry]

Both these brakes are sensitive to setup and require good cables.

On my Gekko the BB5s were appallingly poor, so I swapped to BB7s and had the same issue.

Then removed the two flexible armoured bends from the cable run and fitted Nokon cables. Instant revelation and imacculate stopping power!

Good stiff cables and a direct run will certainly improve these brakes

Which is exactly what Avid specify in their specs/fitting instructions and which no OEM seems to follow....

Pad life; I've gone through a front pair of BB7 pads over a wet hilly long weekend, I always carry spares.

 

[Globalti]

Er, everybody, I've just discovered I've made a big boo boo! I sat down this evening to look at the BB7s and try to work out why they aren't working very well, why they squeal and why they aren't sweeping the whole disc. After some squinting and two attempts to align the calipers I realised that the pads were not fully home in the calipers! You have to sandwich the return spring between the two pads, slip them into their housing then push them positively in until they click into the spring clips on the tops of the calipers. Mine were only partly inserted and were cock-eyed, which explains why I couldn't get the damned things working right.

Now they are properly parallel to the discs, work much better and have that snappy feeling of a well-adjusted brake.

D'oh! And I've been fettling bikes for 45 years!

 

[RecordAceFromNew]

D'oh! And I've been fettling bikes for 45 years!

Nuffin to worry about, since you haven't been fettling bb7's for 45 years...

 

[potsy]

I have been having a little fettle of mine tonight following this guide -
http://www.ecovelo.info/2011/04/15/a-foolproof-method-for-adjusting-avid-bb5-disc-brakes/
Feel much better now, easy to do even for a duffer like me