Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 04-02-12, 08:21 PM   #1
1 guy 1 bike
Junior Member
Thread Starter
 
Join Date: Oct 2011
Bikes:
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Avid BB7 Chirp

I recently built a bike with Avid BB7's and after riding the bike for about 20 miles, my front disc brake started chirping when braking. I've ridden the bike for over 200 miles now and the front disc still chirps when braking. The rear disc never makes any noise, practically silent, though I do admit I haven't used it anywhere near as much as the front disc.

The front disc brakes very well, the noise seems to be the only problem. I've re-installed it to make sure I didn't do anything wrong but the noise persists. Does anyone know what the problem might be, or is this normal?
1 guy 1 bike is offline   Reply With Quote
Old 04-02-12, 08:25 PM   #2
BobLoblaw
Dough Mestique
 
Join Date: Feb 2009
Bikes:
Posts: 349
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Try cleaning the disc with rubbing alcohol and a lint-free cloth.

BL
BobLoblaw is offline   Reply With Quote
Old 04-02-12, 08:25 PM   #3
sirtirithon
Senior Member
 
sirtirithon's Avatar
 
Join Date: Apr 2011
Location: Spokane
Bikes:
Posts: 279
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
My Avid BB7's do it too. Im looking forward to reading the replies. My Avid 5's never chirped or chattered.
sirtirithon is offline   Reply With Quote
Old 04-02-12, 08:48 PM   #4
reptilezs
Senior Member
 
Join Date: Sep 2004
Location: boston, ma
Bikes:
Posts: 2,852
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
did you bed in the pads correctly? 10-20 lever pulls without coming to a complete stop? a complete stop puts more pad material in one spot during break in.
reptilezs is offline   Reply With Quote
Old 04-03-12, 11:11 AM   #5
SlowCrank
Senior Member
 
Join Date: Mar 2011
Location: Portland, OR
Bikes:
Posts: 76
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If you have the bike in a stand (or upside down) are you seeing the rotor rub the pads when you spin the wheel? In addition to cleaning the rotor and checking pad placement, you may also want to check the wheel placement. My front hub is a little off and my BB7s will make a little noise if I don't have the wheel installed just right.
SlowCrank is offline   Reply With Quote
Old 04-03-12, 11:22 AM   #6
MileHighMark
Old. Slow. Happy.
 
MileHighMark's Avatar
 
Join Date: Jan 2010
Location: Boulder County, CO
Bikes:
Posts: 1,798
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Are you running the stock pads? If so, you may want to consider replacing them with Avid's organic pads. Much, much quieter.
MileHighMark is offline   Reply With Quote
Old 04-03-12, 11:29 AM   #7
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 22,233
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1156 Post(s)
I only get noise at very low speeds, in front , then I use the back one..

Avid ships the organic pad type in them , when new?
not the metallic sintered type?

Last edited by fietsbob; 04-03-12 at 03:48 PM.
fietsbob is offline   Reply With Quote
Old 04-03-12, 11:45 AM   #8
MileHighMark
Old. Slow. Happy.
 
MileHighMark's Avatar
 
Join Date: Jan 2010
Location: Boulder County, CO
Bikes:
Posts: 1,798
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by fietsbob View Post
I only get noise at very low speeds, in front , then I use the back one..

Avid ships the organic pad type in them , when new.
not the metallic sintered type.
Really? Every single set of BB7s that I've purchased over the past 4-5 years have come with the metallic pads.

Avid shows metallic pads as OE on their site:
http://www.sram.com/avid/products/bb...th/term-id/289
MileHighMark is offline   Reply With Quote
Old 04-03-12, 01:43 PM   #9
Leebo
Senior Member
 
Join Date: Aug 2009
Location: North of Boston
Bikes: Kona Dawg, Surly 1x1, Karate Monkey, Rockhopper, Crosscheck , Burley Runabout,
Posts: 4,059
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 191 Post(s)
Qr tight? Hub tight? Headset tight? Did you use new rotor and pads?
Leebo is offline   Reply With Quote
Old 04-03-12, 02:15 PM   #10
1 guy 1 bike
Junior Member
Thread Starter
 
Join Date: Oct 2011
Bikes:
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've done everything everyone has mentioned, there's no rub when spinning the wheel. Everything was installed brand new. Mine came with metallic pads, I might change over to organic pads in the future but I don't think that's the problem, because the rear disc makes no noise at all. fietsbob mentioned his front disc is noisy at low speeds, mine chirps a lot at low speeds, the chirp quiets down at higher speeds and the noise becomes a light squeal. I'll try re-torquing the disc bolts to see if that does anything, I'll report back.

I'm sure there's a reason, I hope I find it soon enough
1 guy 1 bike is offline   Reply With Quote
Old 04-03-12, 03:40 PM   #11
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 22,233
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1156 Post(s)
Are the pads them selves color coded , which is which?

I look down and all i see is the return spring tweezer.

Last edited by fietsbob; 04-03-12 at 03:50 PM.
fietsbob is offline   Reply With Quote
Old 04-03-12, 03:59 PM   #12
MileHighMark
Old. Slow. Happy.
 
MileHighMark's Avatar
 
Join Date: Jan 2010
Location: Boulder County, CO
Bikes:
Posts: 1,798
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
The organic pads come in two flavors -- steel and alloy backed. The organic ones that I've used have been marked with an "O" on the back plate.
MileHighMark is offline   Reply With Quote
Old 04-03-12, 04:24 PM   #13
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 22,233
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1156 Post(s)
Man,that means taking then apart. the mild squeak does not bother me, just the OP.
I can wait till I replace them.

saw some replacement pads banded, mixed organic central and metallic on the edges.
didn't come from Avid, I think Clarks from England, they probably source in China too..
fietsbob is offline   Reply With Quote
Old 04-03-12, 11:40 PM   #14
skiph
Senior Member
 
skiph's Avatar
 
Join Date: Oct 2006
Location: Oregon coast
Bikes: '06 Trek Pilot 5.2 SPA, '07 BikesDirect frame build, '10 GF Wahoo disc
Posts: 408
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Picked up this idea on another bike forum site:

Are the lower edges of the front brake pads hitting on the rotor 'spokes' when you apply the front brake?

That is, are the lower edges of the brake pads running below the actual braking track of the rotor?

In some other posts on another site...the caliper wasn't far enough from the axle center relative to the outer edge of the rotor, so the pads were hitting on the rotor 'spokes' when they were applied.

The guy with the problem used some spacer washers to move the caliper farther out along the rotor's braking track so the lower edge of the pads were clamping fully on the rotor braking surface, no longer hitting the rotor spokes.

To test if the pads were now riding fully on the braking track, he drew a radial line in a couple of places on the braking track with a Sharpie felt tipped marker, and could see where the black ink was rubbed off.

Then another poster said to watch the TOP edge of the pads to see they did not develop a ridge if the top edge was now off the outside of the rotor. He suggested just sanding them flat from time to time if that was the case.

Hope this helps.
skiph is offline   Reply With Quote
Old 04-06-12, 05:28 AM   #15
p2templin
Senior Member
 
Join Date: Sep 2011
Bikes:
Posts: 403
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
^^^
I discovered once that a rotor wasn't centered, so if you viewed it from the side you'd see it going up and down a bit. I removed the wheel, loosened the screws, rotated the disc against the screws, and retightened. Much better.
p2templin is offline   Reply With Quote
Old 04-06-12, 08:24 PM   #16
drbenjamin
Senior Member
 
Join Date: Oct 2010
Location: Redmond WA
Bikes:
Posts: 119
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Related question - I have a BB7 on my front wheel, and it has started making a grinding sound as if dirt/sand is trapped in the pad. Should I be cleaning the pads with any frequency? Any other explanations for a grinding sound?
drbenjamin is offline   Reply With Quote
Old 04-06-12, 11:00 PM   #17
1 guy 1 bike
Junior Member
Thread Starter
 
Join Date: Oct 2011
Bikes:
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by skiph View Post
Picked up this idea on another bike forum site:

Are the lower edges of the front brake pads hitting on the rotor 'spokes' when you apply the front brake?

That is, are the lower edges of the brake pads running below the actual braking track of the rotor?

In some other posts on another site...the caliper wasn't far enough from the axle center relative to the outer edge of the rotor, so the pads were hitting on the rotor 'spokes' when they were applied.

The guy with the problem used some spacer washers to move the caliper farther out along the rotor's braking track so the lower edge of the pads were clamping fully on the rotor braking surface, no longer hitting the rotor spokes.

To test if the pads were now riding fully on the braking track, he drew a radial line in a couple of places on the braking track with a Sharpie felt tipped marker, and could see where the black ink was rubbed off.

Then another poster said to watch the TOP edge of the pads to see they did not develop a ridge if the top edge was now off the outside of the rotor. He suggested just sanding them flat from time to time if that was the case.

Hope this helps.
Quote:
Originally Posted by p2templin View Post
^^^
I discovered once that a rotor wasn't centered, so if you viewed it from the side you'd see it going up and down a bit. I removed the wheel, loosened the screws, rotated the disc against the screws, and retightened. Much better.
That's interesting, I checked the brake mark on my front rotor and it's hitting the spokes very very slightly in three places. I'll re-center the rotor and report back if that fixes the problem.
1 guy 1 bike is offline   Reply With Quote
Old 04-07-12, 08:23 AM   #18
1 guy 1 bike
Junior Member
Thread Starter
 
Join Date: Oct 2011
Bikes:
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I re-centered the rotor and that pretty much completely got rid of the noise, thanks!
1 guy 1 bike is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:55 AM.