Bikram

I'm about to pickup a new bike with Shimano hydraulic disc brakes. During a test ride of the floor model, I noticed they made a "friction-y" noise when I applied the brakes. NOT an annoying squeal. Just a noise that sounds like "shhhh".

This is my first experience with disc brakes. My old rim brakes were practically silent. While disc brake noise is not super annoying, I'd prefer it not being there.

Is this noise normal?
Will it go away after break-in?

PS: this is my first post--Hello!

RPK79

I don't have any experience with disc brakes, but I imagine that is normal considering the materials and forces involved.

obed7

I have only had one bike with hydraulic disc brakes, I sold it after about 6 months, but do not remember any noticeable noise from the brakes.

topflightpro

There should be no noise from the brakes when you are not actively engaging them - even then, there should not be considerable noise. It could be that the brakes are poorly adjusted and rubbing the disc.

bt

disc brakes can make a nice sound when using them.

almost like a flutter sound.

RJM

Well...my xt brakes on my mountain bike do this every so often when it gets dirty and my friend's disc brake equipped cross bike does it seemingly all the time. Tell the shop to see if the rotor is slightly bent when you get your bike...that's a possible fix.

UnfilteredDregs

Front wheel?

The disc isn't aligned with the caliper.

Can be for any number of reasons, improper QR torque being typical, pads dialed in too close to the rotor, caliper wasn't properly aligned when installed...can be temporary while riding because of rotor heat buildup, flexing the frame, road schmeg, etc..

Rotor should spin freely and silently through the caliper, no rub, or grab. Make sure your shop goes over the brakes, and it's something you should learn how to adjust yourself.



My car does it..."shhhhhhhh" very lightly, like a jazz drummer using a brush on a cymbal. Dealership says it's fine. Annoys me.

Bikram

Thanks everyone. I wasn't clear enough, sorry: the noise only comes about when the brakes are APPLIED. In a way, it wasn't unexpected; there's greater force needed to slow something down when it's concentrated so close to the hub. It's just that it was more noticeable than I thought it'd be. Bike store says the noise will go away after a while.

It's just that I've been spoiled by the near complete silence from my very old (original pads!) cantilever brakes even when braking moderately hard.

Also, I noted that I slagged the wrong company. The brakes are by Shimano, not Tektro.
I've edited my original post. --what a lame 1st post!

bt

yes, that's true and it's also when the squealing begins.

CafeVelo

Welcome to the disc era.

DirePenguin

I've got Tektro Novella's (lower-end mechanical discs) on my Trek hybrid and after about 2,000 miles they still make a somewhat audible "shhhhhh" when applied. But, they don't squeal and don't make a sound or rub when not applied.

hairnet

Organic pads are usually quiet while metallic pads have more of that "shhhh" sound.

UnfilteredDregs

Pads need to be broken in , that's for sure but, brake noise should be minimal. there is a right sound, and plenty of wrong sounds.

bt

lololol

UnfilteredDregs

I'm sorry you don't know how to maintain disc brakes.

Stucky

Here's a graphic on comprehensive bicycle disc brake maintenance, which will solve all problems:

winston63 

My experience with metallic pads is that they always make noise when you brake. And, if they get road grit in there (which happens quite frequently when riding in the rain) they can scream pretty loudly. Despite this, I do like the braking performance they provide.

I haven't tried organic brake pads though, they are supposed to be quieter.

bt

lol they all squeal, just pick which pitch of squeal you like best.

UnfilteredDregs

They don't have to.

...and no.

bt

I'm sorry.

winston63 

I forgot to welcome you to the forum -- Welcome!

One thing that I didn't say is that (again, in my experience) the noise will get quieter after the brakes are bed in. They can get much louder if and when grit gets in, but they can be cleaned. Even if you don't clean them, this doesn't seem to affect braking performance.

Rowan

How "delicate" are the holes in the discs themselves. I've found that the more "delicate" the pattern, the more noise the brakes are likely to make because of the greater amount of edge going past the pads.

However, judging on recent experience, disc warp does have influence on the amount of noise the OP is discussing. I have one disc out of the eight on the family's bikes that makes more shhhh noise than all the others, and that is the one that is warped the most.

Also, bedding in the brakes is another factor -- speed up, brake hard; speed up, brake hard; speed up, brake hard; or just ride a steep downhill with the brakes applied will do the trick.

I like the concept of disc brakes because replacing rotors and pads are cheaper than replacing and relacing rims. Plus, with the right actuation set-up, they really do work reliably and consistently.

Also, further questions perhaps should be directed to the MTB forum where disc brakes have been in use for ummmm.... a long time.

bt

fixed

DanelleF

so you don't like disc brakes? I just ordered a bike with disc brakes. I heard that all bike will eventually have disc brakes. Disc brakes were also better for down hills?

Stucky

Disc brakes are over-kill for road bikes. Unless you're descending literal mountains in a very wet climate, regular rim brakes work every bit as good; add less weight to the bike; less expensive; offer greater compatibility; etc. There' nothing wrong with discs, per-se; it's just that for 95% of riders, they are unnecessary; and it's like the bike industry is just pushing them so that everyone will want that which is "new and different"; and to foster incompatibility [i.e. planned obsolescence of older stuff]. But, I mean, they'll work just fine on your new bike, so you needn't worry about it.

Hey, enjoy that new bike!