Avid BB5's
 

Ive recently bought, a specialized Hard Rock Comp, and It came with Stupid BB5's disk brakes. The brakes worked fine for a couple of weeks, but now they are losing power, when i lock the front brake, it wont lock completely.

I serviced the brakes and tuned them up again, but the rotor still turns when clamped by the pads.

Any body got any tips to improve the stopping power, and I know your going to say buy BB7 or Magura's but I havnt got the money at the moment after upgrading drive chain, forks etc.

BB5's are very good brakes, no need to replace them. Sounds like a set up issue.

I've been trying to kill my stock bb5s for 2 years now, so that I can justify upgrading them. Unfortunately, they stop for me just fine. The main issue I have with them is the single-sided adjustment...makes tuning them for max stopping power a bigger PITA than something with dual-sided adjustment. It also exacerbates issues with a slightly warped rotor. I end up having more space than I like between the pads in order to accommodate the wobbly rotor(finally got sick of unsuccessfully trying to tweak the rotor back into shape), which translates to longer travel in the brake lever.

I'd suggest looking at 2 things:

1) You said you just got your bike...If you bought it new, perhaps the brake cable has stretched enough that your lever travel isn't enough to fully apply the brakes. Try taking some slack out of the brake cable and see if it helps. FWIW, most LBS new bike purchases include at least 1 free "tune up" which is intended to take care of such things as initial cable stretch...etc.

2) If #1 isn't the issue, go thru the instructions on setting the pad/rotor clearance. It's possible that somethings is out of whack, or the pads have worn enough to result in a gap that's big enough to cause the same type of symptoms #1 would exhibit...i.e. %100 application at levers(full lever travel) not resulting in %100 application of force at the rotors.

Put another way, it's possible that the lever travel stops before the pad has been moved close enough to the rotor to provide adequate stopping force. Solution is to either remove some cable slack, or adjust the pad closer to the rotor in the "open" position(or both).

Bottom line is that probable556 is right, bb5s stop just fine when they're tuned correctly. If they're not stopping for you(if the rotor is still spinning when you apply the max force to the lever), then they're not set up just right yet. The set-up is not allowing you to apply as much force as these brakes are capable of.

Its not that there not really stopping me. I'm quite good at bike mechanics so ive adjusted the breaks, alighned the pads, tightened the slack etc.

When I pull the levers, the two pads are in tight contact with the rotor, but If go to hop over something, or shift my weight, the rotor will slip a small bit in the pads.

Its so annoying and has caused me a few smalll embarrassing falls.

Did you break the pads in properly?

Ive done about 100miles in couple of weeks with them, all off road so I would think they are broken in at this stage, should i clean the rotor/pads?

What's the BB5 vs BB7 difference?

With my Juicy 5's I had to do about 20 consecutive hard stops before the pads were "broken in" according to Avid. Hitting the trail is not considered breaking them in. This could be your problem but I can't say for sure.

I've got the same issue with my BB 5's. This is my first set of discs and i have more to learn on set up but still i hate them. I took mine back to LBS a couple months ago to see if he could improve them. He did a little but they went right back to being squishy.

I absolutely hate disc brakes. Give me rim brakes any day of the week.

I don't really know anything about them, but I did just happen to read a good article on adjusting them on Blue Collar MTB http://bluecollarmtb.com/2006/10/30/...al-disc-brakes might help...

Nic

What???? Really????

Nevermind figured it out.

BB5 - one adjustment for pads
BB7 - two adjustment for (both) pads

technically, you can adjust both pads on the bb5s. but the bb7s have red tool-free adjustment knobs on both side of the caliper, whereas the bb5 has just one on the inside and you'd have to use an allen key to adjust the other side -> by taking up more cable and clamping it down, or using the brake lever barrel adjuster. the bike i have has bb5s.

and from what i heard (don't quote me on this) there's little or no difference in braking power... however, the bb7 shares pads with juicy 5s and 7s, but the bb5s have their own circular brake pads (which have a smaller pad surface).

I've just realised, the cause of this loss in power may due to a bit of Wd40 getting on my rotors and pads.

Anybody got any ideas how to get rid of this contamination?:eek:

This was the first thing that popped into my mind. How did you "come to realize" that wd 40 got on them?

for the rotor, use rubbing/isopropyl/denatured alcohol and a cloth/paper towel to clean any oils off of it. that's the best way to properly clean your rotors.

as for the brake pads, take them out (don't lose the little metal clips! and also, take note of the colours, one is blue and one is black for the outside and inside pads) and then boil them in water, and/or baking them in your oven, around 400 deg. fahrenheit. i've personally never tried these, though i've heard of other people doing it.

if the brake pads are still screwed up, you're out of luck. you probably have to buy new pads.

i try to never get oil of any sort on my rotors. i never use spray lube on my chain (gets all over the place) and no one ever touches my rotors (finger oil can decrease your braking performance, though not by much in my experience, though some people on forums say so).

Pete yet again, youve shown how the world is a better place with your help, Im so glad u are here to help!

I've been mountainbiking since the age of about 12, and always serviced my bikes myself and never had a major problem before. For me, my love of bikes is also about servicing them and tuning them not just riding, we dont all have trust funds to pay some mechanic every time our brakes need a tune up.

I didnt spray wd 40 on the pads intentionally u idiot, but just like your conception, mistakes do happen !!!

Practice makes perfect, learn from your mistakes!!! and so on so forth.

Anyway this thread is people sharing advice and knowledge so buzz off little man!

Funny enough, I took the calipers off there bracket to examine them a bit closer and "realized" that there was distinct smell of WD 40 (I actually like that smell)

I would suspect the WD 40 dripped from the top of my new forks when I was cutting them to fit my head set.

Im normally quiet carefull about things like this (neat freak), but theres definatly a smell of wd40.

(Cream Soda) Im a small bit aprehensive about baking my pads, where did u get that info from?
Id guess this heat treatment would cause them to shrink/exand and also affect there density, there fore there wear and stopping power.

Go buy some new pads, clean the rotors well, and you'll be fine. And WD-40 isn't something you should ever really use on a bike... there are a few exceptions but for the most part keep away from the stuff.

+1

Cue Ric0.

LMAO........:D


Anything that displaces water is the worst thing you could ever want around your bike. Find something that attracts water instead. Keep up the good work.

I find it's perfect for dressing some bolt threads or pivot points but ,personally, I wouldn't use it for much else on a bicycle, especially if there will be a good deal of potential heat/friction, such as bearing races and things like that. That's just the way I see it. You can use whatever you like. :)

Why did cutting a steer tube cause WD40 to cover the brake pads??

I usually cut them with a hacksaw or pipe cutter...

I was using a pipe cutter, a small bit of Wd 40, helps for a cleaner cut, with less burs. I know not to go lubing my bike with WD 40.