Clacking / Clicking noise when applying rear brake on
 

Hi,

Just bought a 2012 Cannondale CAAD10 with the Ultegra 6700 groupset, and during my first couple of rides I've noticed that when applying the rear brake there is a rhythmic, loud clacking or clicking noise coming from the rear of the bike. This only occurs when riding the bike, doesn't seem to happen when I lift the rear wheel up to spin it and apply brake.

The frequency of the noise suggests it *may* be tied to the rotation of the wheel but I'm not a 100% sure of this.

Had a search around this site and the web in general, including Sheldon Brown's site, and the only thing I've come up with is noise from bearings some people have had problems with in this model of bike, but that seems to be something that wouldn't be tied to braking (best guess on my part this).

So yeah, at a loss. Any help would be really appreciated as obviously not too keen to go far on a bike with suspect braking noise, so kind of annoying :-)

Check the rear rim for a misaligned seam or a dent or other irregularity. Also check that the brake pads are aligned properly on the rim's brake track and not touching the tire or a spoke.

Hi Hillrider,

No dents but the seam is easy to find with my finger nail. Doesn't seem misaligned though, certainly doesn't produce the noise when I've had a mate apply brakes with slowly increasing strength while I lift back wheel and rotate the pedals hard.

Brake pads are nicely aligned too.

Thanks for the suggestions though.

I'm eyeing the plastic dork disk between the wheel spokes and cassette suspiciously at the moment, wondering if that could some how be the culprit as there is something...plasticky...about the noise....

Regarding the oft-maligned dork disc (AKA spoke protector), it is unlikely to be the source of your noise and you might be glad you have it if your chain should somehow shift into your spokes. Is there perhaps a brake wire end coming into contact with the wheel? If the bike was bought from a bike shop I'd have them look at the noise as a warranty issue.

If you only hear the noise with the brake on, and not while pedaling and coasting, then it's a good bet that it's brake issue, and not related to the spoke disc, or anywhere near the hub.

Like HillRider I suspect that it's the rim joint passing the shoes, but it could be anything on the rim as it passes the shoes. Also, it might be play in the brake's pivots which click as the joint bumps the shoes.

Try this experiment. Find a hill you can coast down with decent speed. Remove the rear wheel and mount it backward (cassette on left) making sure the chain is over the hub as it normally would be. Push off and coast up to a decent speed and apply the brakes. Is the clicking better/worse or just different, if so it's the rim, and the solution is to use a file or sandpaper on a block to improve the rim seam slightly. Don't strive for perfection as you don't want to remove more metal than necessary, and the brakes will finish the job over time.

You might also check that your pads are not catching on a piece of misaligned rim label.

Hullo,

Definitely no brake wire getting into the wheel I'm afraid. Good to know the spoke protector isn't likely to be the cause though, thanks.

I think you're on the right track. Given I can't detect the problem just spinning the wheel and braking, I reckon it requires force/speed of actually being in motion to jog the brakes enough too make the noise. The brakes seem pretty solidly put together too.

The seam in the rim is detectable but quite slight, and very similar on both sides of the wheel though so if it is this, I doubt it will sound much different if I flip the wheel. I'll have a bash at it with a file though, and see if this improves things.

It's chucking down with rain today so may be a couple of days before I get some free time to experiment and come back with an update, but thanks for your help (and everyone else's too)

The idea of reversing the wheel wasn't to solve the problem (though it often does on fronts) but as a diagnostic tool to verify that it's related to the rough joint. Even if the joint is off on both sides, reversing the wheel changes how the shoe passes over it. Picture the difference sliding something up vs. down a shingled roof, or rubbing your hand up in either direction over a cheese grater to see the point.

Once you've decided it is the rim joint, hang the bike, gently apply the brake, and rotate the wheel back and forth passing the seam through the shoes and look for movement on the arms, or feeling if it snags.

Hi.
You'll have to excuse me reviving an almost decade old thread, but I recently ran into a similar problem, and this seems to be the only discussion about it on the entire internet.
I thought I should share the solution for anyone who ever runs into this problem again. Here's to the posterity, forever plagued by the same headaches, yet none the wiser...

If you ride on either WH-6500 or WH-7700 wheelsets and start hearing a pretty loud clicking sound while braking, it most likely isn't the rim joint, but the tire guide screws touching the spokes.
Under "normal conditions" i.e with new-ish brake pads set correctly, the clearance between the tire guide screw and the spokes (which on both of these wheelsets bulge out a bit, compared to normal bike wheels) is 1-2mm at most when braking.
As the pads wear down the tire guides will start touching the spokes, making a rhythmic click click click sound whenever you brake hard.

The solution is simple. Removing the tire guide screws makes the sound go away. Replacing the brake pads might also work, if you feel like doing that.
In extreme cases the brake shoe fin might start touching the spokes. I wouldn't worry about it at that point, I'm still not replacing my brake pads!!