Bicycle Mechanics - BB5 Disc Brakes Feel squishy

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chefisaac
08-01-12, 10:59 AM
I do not know much about bike mechanics (planning on going to some classes) but the last few days my brakes feel squishy. I can pull them all the way back and the stopping power really sucks and not what it was before. I could actually get no stopping from my back brake. So this morning I was cleaning the bike up (after the rainy commute) and I decided to screw around with the brakes. Granted, I was nervous because I had no clue what I Was doing.
Here is a picture:
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I am not sure if I did this right or not so please let me know if there is something I should have done differently.
I first loosed the allen screw and then tightened the brake cable. I did this by hand. Should have used pliars. Then I tightened it back up and it was fixed but the disc was rubbing so I rotated the red nob and it worked.
Was this right?
This is the guide I use. Actually, it's quite easy to do. I cut my shim from a milk jug. It seems to be just the right thickness. The pictures aren't very clear. The shim goes to the outside of the rotor. If you follow the instructions you should have no problems. It's well worth it to buy a T25 screwdriver for this job. Makes it that much easier. After you've done it once, it is a 10 minute job. Mine come out feeling better than when the bike shop does it. I don't think they use this method.
http://bluecollarmtb.com/2006/10/30/how-to-dial-in-avid-bb5-mechanical-disc-brakes/
chefisaac
08-01-12, 04:38 PM
should i have done that instead of tightening up the brake cable?
LarDasse74
08-01-12, 08:26 PM
If the rotors and pads have not been contaminated with oil (from your hands or other maintenance procedures on the bike) then adjusting the cable and pad adjusters is sort of all you can do.
One other possible thing that may be less than ideal is the cable routing. It is hard to tell from the picture, but you may have some kinks or overly-tight bends in the run of cable housing just before the brake caliper. This can increase friction and greatly reduce power. Like I said, hard to tell, though.
JonathanGennick
08-02-12, 05:38 AM
It sounds like the OP pulled slack and/or added tension to the brake cable. Nothing wrong in doing that. The part about adjusting out the rub using the inboard pad adjuster when it is the outboard pad that is affected by the cable doesn't really square, but perhaps the rub was there all along and just happened to get noticed while doing the adjustment.
If all the OP did was to pull the cable tighter, and the brake is working, then I'd say all is right w/the world. Ride the bike and be happy.
The following is also a good read: http://www.ecovelo.info/2011/04/15/a-foolproof-method-for-adjusting-avid-bb5-disc-brakes/
I also have BB5's and use the business card adjustment method. Like it was said after doing it once or twice, it is a < 5 minute job.
One other thing that will effect the performance and feel of the brakes is the cable housing. Since mine where not original equipment on the bike I had regular spiral wound brake housing. The brakes felt mushy. I changed to compressionless housing and it made a world of difference. Nice and solid.
Good luck.
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