Chattering disc brake?
 

I know that cars, when the rotors are worn, will have brake chatter. Can bike disc brakes?

I thought it was a loose headset and it was a bit loose (there was a clicking when I put on the front brakes or even at a standstill) which I fixed yesterday (Thanks Bicycle Mechanics forum!). However, there is still a chatter so I'm suspecting the front rotor.

Is it possible to see or, with my hands, feel changes in the rotor?

the screaming sound when you are wet braking is a high frequency audible version..

It's not possible for ME to see, from Oregon, I can say that much .. make an LBS visit.



inspect pad surface , sand off glazing , clean off disc , Hold brake on and while gripping the disc , loosen and retighten the post mount bolts .

the frame tab to ISO adapter should be tight .

Ooops, sorry, let me hold it up a bit higher! :lol:

OK, I'll do/check those things.

Define 'chatter'. What does it sound like? Does is make it all the time,or intermittently?

Maybe chatter isn't the right word as it implies a sound but there really isn't a sound, just a vibration in the front fork when I engage the brakes. It happens every time I engage the front brakes, but not at any other time. The rear brakes are smooth.

Yesterday on my dry commute home, I had the same brake shudder/judder/vibration for the first time on my fork from the BB7 front brake. I have had shudder on my cantilever brake of my Surly LHT before, but after I changed out the stock pads I haven't noticed anything. I would really like to get some feedback on this as well.

Oil on pads can cause something like this.

Getting oil out of pads, well, that's the bad news. Not likely... swap pads, wear gloves, and keep the oil off.

That's a cheap "solution" and they are old enough on my bike that this should be considered.

My BB7s were doing that about a year ago. Pads weren't that old, -just one winter's worth of use. Replacing them solved the problem.

I must say that as a relatively new user of disc brakes, they aren't as great as you all had lead me to believe. ;)

They stop well enough but I've had the above problem along with horrible squealing when wet. The rotors have needed some truing and initial adjustment (on install) was a pain to get right. Why wasn't I informed?

Is this a common issue? Mine are silent when braking in the wet. Is this issue more common with certain rotors or pads?

Could be the pads. Have you checked to see if anything's loose? Check the skewer,caliper,and rotor just to be sure. Also check to make sure the rotor is straight.

Depends on the pad/rotor combo. My M495's with Shimano pads are silent unless they get really cruddy,then pne good stop shuts them up. My BB7's only squeal at first when wet,then they scrape themselves clean and quiet down. I converted my Pt Reyes to BB7's but left the stock Hayes rotors on. They squeal a little even when dry,it just isn't bad enough for me to bother with swapping the rotors or pads.

i did a little happy dance when i junked my bb7s and switched to deore lx hydraulics (now multiple upgrades later i'm running 775s). the local co-op did not even want the bb7s because they had a free/cheap part box full of used ones.

Did you break in your pads by braking hard a few times? I usually remember to do this, but forgot on my new bike (BB7s) and got the chatter. I was able to fix the problem by braking hard 2-3 times after the problem appeared.

Don't give up on the discs, tjspiel. Remember what a pain it was to adjust caliper brakes with only two hands. You'll appreciate them when you have to do a panic stop with a lot of weight on board.

I've been trying to inform people about discs since I signed up with the Bike Forums in 2004. I get barbecued every time I bring disc brake shortcomings. I can hear the wood being gathered right now. I've had discs since 2001 and I have yet to find anything superior about them.

And, having just done a bleed job and looking at having to do the seals on a brake lever, I find nothing redeeming about hydraulics. I can repair anything on a bike and I have done everything you can do to a bike short of welding but I would seriously consider paying a mechanic to do a bleed and/or rebuild job.

No local co-op that I know of would refuse any parts. My local co-op will take any bicycle part made from 1870 to present. I also find a "free/cheap parts box full of them" hard to believe. I live in a bicycle crazy area that has a huge of mountain bike riders and my local co-op sees very few used disc units of any kind. Any that do show up are quickly snatch up...even your hated BB7s. If anything, a BB7 will be snatched up faster than anything else.

They simply said they did not need them. And as proof they brought a huge box full of disk brakes including multiple bb7s that were in better condition (mine were quite scuffed and worn). There is a bias against disk brakes in PDX and this shop even removes disk brakes when reconditioning the bikes they sell/give. This co-op also also suggests (requires) a "donation" of $25 for giving them a perfectly function bike...Portlandia at its finest!

I'm not planning to give up on them. I just hate squealing brakes. They will quiet down if I pedal for about 30 yards with the brakes lightly on, - until something else gets splashed on them.

The chatter came after a few months of use, - winter use. I wasn't too happy because the pads were basically new and I made sure to get organics after hearing they squealed less. It didn't happen this year so maybe I just got a bad set of pads.

I do find them more reliable than rim brakes for stopping in sloppy weather, but I had really been expecting something an order of magnitude better than rim brakes. For me the expectations included near silence. They're pretty much a fail in that regard unless you only ride in dry weather. And if you only ride in dry weather, rim brakes work just fine.

I'm now scared of hydros in extreme cold because of what happened to SRAM. Many folks have said there is a night and day difference between hydros and mechanicals but I doubt hyrdos squeal any less. Plus there was supposed to be a night and day difference between discs and rim brakes and I haven't really seen that either. They are better in wet weather and that is important enough to me that I'll be holding on to them. I'll just grit my teeth through the squealing.

Put new Disc pads , Kool Stop, organic type , cleaned the discs an the calipers , and put them back together ,

(bike friday Pocket llama 20" wheels, 160 discs) and the BB7 brakes have been working fine , since..

I rode my bike with hydraulic BB7, I mean, Juicys (thanks @fietsbob) this winter with no real problems. The only and minor issue, was that the pads were "slow" to return and by that, I mean, that when I pressed on the brake lever the first time, the brakes responded as well as they seemed to during the summer but, if I needed them again, within a few seconds, I didn't need a full pull to engage the pads, just a partial pull. However, within about 30 sec or maybe 60 sec, the pads had fully retracted.

By winter, I mean temps lower than -30C/-22F.

actual bedding in recommendations given locally, on new bikes, is 15 or so modulated braking episodes , not a few heavy ones ..


But ..... BB7 is a cable brake,, Avid's hydraulics are called Juicy ..(various models)

Corrected, thanks

ime, having two hydraulic pistons (often designed with set back) definitely provides better clearance and power.

people have been racing hydraulics in winter downhill for a long time:

Glacierbike Downhill, March 2015 - Saas Fee - Saastal

Maybe I lucked out, but I have several years now of trouble free, squeal free (except when wet, and initially only) and maintenance free (other than new pads) SLX hyrdaulic disc brakes. I'm no master mechanic by any stretch. Maybe SRAM and Avid disc brakes are inferior. I regularly swap out wheels without any adjustment. Not sure why some folks seem to have no issues, and others just can't seem get them to work. And they do provide superior braking performance in all conditions.

That's because your experiences are yours and not other people's,but you refuse to acknowledge this. You complain about how easily rotors get bent,but this hasn't been my experience at all. You've also talked about how rim wear isn't a big issue,yet other posters have stated that for them it's been a real problem. You need to understand that your experiences are not universal constants.

Power isn't really the problem. It's the squealing and sometimes the alignment/rotor trueness.

A downhill race in relatively mild temps doesn't do much to reassure me but Jrickards post did. I don't want any air getting into the system because the seals aren't flexible enough to deal with extreme cold.

What's disappointing is that I had the impression that BB7s were the Cadillac choice. Now I'm hearing that they're basically junk and that hyrdos are the real McCoy. Frankly I'm a little skeptical. If I had to guess, I'd say they're probably better, but still not a panacea.

The fact that rotor trueness, brake squeal, installation issues, etc. comes up quite often on the Forums and at my local co-op where I have to help solve these problems as well as interactions with other riders says that my experiences with disc brakes aren't just mine. If I were the only person experiencing these problems, I could be persuaded that I'm somehow special. tjspiel is experiencing the same kinds of issues that I've experienced.

Don't take what a few around here say about BB7s to seriously. While the BB7s are more like the Chevrolet of mechanical hub mounted disc brakes, there really isn't a "Cadillac" choice when it comes to mechanicals. More like a bunch of Fiats, Ladas and Yugos. The brands of mechanical discs that I've worked on that aren't Avid are really poor.

Hydraulics have their own quirks. Cold temperatures are always a problem with elastomer seals because the polymer stiffens with temperature. There are seals that might do well in cold temperatures but they are expensive.

All brakes have pros and cons to them.
Cantis clear mud well for cx riding and can be set up wide enough that an untru rim will not rub. For actually stopping a bike quickly they suck. I have never had them set up to stop with anything close to the power and confidence as v-brake. The chatter of cantis is unreal. I thought my carbon cx fork was going to shatter when i had cantis on it.
V-brakes work jsut as well as disc when it is dry, they have nowear near the power in the wet.
Road calipers, see v- brakes.
All rim brakes wear out rims, some faster than others. My mavic a319 rim is done after 2 years of ridng. Winter crud and trail riding/mud have destroyed it.

Disc brakes stop in the wet. The wheel can last as long as the hub does. Warped rim can be ridden no problem. They make racks and fenders a pain to install, they can squeal like mad in the wet ( which i will gladly deal with as I like being able to stop) cost alot more, and canbe harder to adjust. They can shudder if the rotor is not straight. Long descents can cause the pads to heat up and lose power. Long descents on rim brakes can cause rims/tires to blow.

There are many threads on BF about the benefits of all brakes. I'll take my bb7s over any rim brake for the stopping power in the snow, rain and mtb riding. Nothing better than a long technical downhill with wet vbrakes. Cantis just plain suck, have always felt anyone who claims their cantis can stop as well as v-brakes has no idea how to set up v-brakes. I got my cantis setup by a national cx rider.
They sucked.
I had some initial issues with discs, mainly the pads rubbing the rotor. I spent about 10 minutes on google and figured out how to adjust a warped rotor, align the callipers so the rotor is centred, adjust the pad distance to the rotor.

For the best stopping in all conditions disc brakes are the best choice. There are people who dont believe this, but there are people who believe the earth is flat.

I also believe the main reason people on forums, in coops and customers in shops dont like them/have issues with them is because they dont know how to set them up, which is why they are on the forums, in the coops and asking at the shop.

^^^^ Well said. Never has any problem with hydraulics in New England cold.I have 3 sets of BB7's that work flawlessly. Set it and forget it. I might look at the pads once a year or twist the barrel adjuster. I find the BB7's work best with a matched lever , like the speed dials.

Amen. I've purchased a good half dozen new bikes that I had to properly set the discs up on after I got them home. I had a client come to my clinic who was told by a local shop she needed new rotors. I tweaked them with my adj wrench,and two years later she's riding the same rotors with no issues.

A little bit of noise, squeeling, chattering doesn't bother me...I did have problems with shimano deore hydrolics, the seals would leak in winter. Had it rebuild and it kept happening again. Got rid of hydrolics and got BB7's. I like BB7's. Very simple to maintain. The only problems I had with BB7's was too much road salt getting into them and eventually making them seize up. Had to take them apart completely to clean and scrape all the salt buildup. I think the reason it happened was because I never used to rinse or wash my bike during winter. I learned my lesson, and from now on I will rinse the salt out more often.
The best thing about disc brakes is they will save your rims from wearing out.