Part 1 Rim Brakes – Caliper Style
If you have rim brakes, then you have probably suffered from brake squeal. Like the cry of a banshee being eaten by a sphinx, it may be one of the most unpleasant sounds ever know to human kind. And unfortunately it is not a mythical beast from the lore of years gone by, it is a very real and terribly annoying symptom of a bigger problem: maladjusted and/or poorly maintained brakes. Here in this very blog, step by step we will look at diagnosing and fixing the piercing squeal of brakes.
Cheap rims and Cheap brakes: the exception and why you may never find silence
Unfortunately there are some brake and rim combinations that are next to impossible to silence. Inexpensive steel rims and less costly caliper brakes sometimes just make noise. The compound of the brake pads just don’t jive with the rim material and there is little to no adjustment that will remedy this situation. These brakes also lack the ability to adjust the angle at which the brake pad contacts the rim – short of bending the arms with pliers, which still may not stop the squeal. I don’t want you to give up hope but it doesn’t look good if you have a cheap and cheerful brake set up, they may also be noisy.
Good contact and Toes in, keeping the pads adjusted correctly
One of the most prevelant causes of brake squeal is maladjusted brake pads. Make sure that your brake pads are properly aligned with the braking surface of your rims and double check that they are not diving below the rim while braking. To adjust this, which I am sure you have figured out, but just in case you haven’t and you are afraid to ask you will need to loosen the brake pad by using the set screw on the outside of the brake pad by turning it counterclockwise, I find a tri-key is the easiest tool for this job.
Also ensure that the pads contact the rim at the same time. Now is a good time to double check that your wheels are sitting properly in the frame dropouts, trust me, it sounds simple, but is commonly missed. Open the quick release and and lift to ensure that the axle is sitting evenly in the fork drop outs. If the wheel is all good and one brake arm is contacting earlier than the other, you can adjust the brake tension with a small set screw(s), just one for caliper style brakes and one on either side for V or linear pull brakes. These screws can either be a small allen key size or a smal Phillips head screwdriver. Turn it clockwise to increase tension and pull on that side.
Next check to see if the pads are properly « toed in. » What this means is that when adjusting the pads you should ensure that the front of the pads contact the rim before the rest of the pad, the force of the wheel contacting the pad will flatten it out when you go to stop, but this can really get rid of the squeal.
A dirty rim, why things keep slipping by
Did you know that your rims are porous? How about that when you are braking they will remove tiny, little parts of your brake pads which will build up on your rims surface? At the same time your rim will give up little pieces of itself to the brake pads when being used. Over time this chummy give-and-take creates a slippery situation that can be difficult to remedy. Sooner or later your brakes can actually eat through the wall of your rims, it sounds crazy but it’s actually true. Don’t be scared it takes a decent amount of time to totally kill a set of rims, but the lack of this danger is certainly one of the draws that disc brakes present.
How do you fix this? I’m glad you asked. Have a look at your pads, if they are shiny then take some fine grit sandpaper and remove the sheen. If while you are looking at them you also notice that they have well defined shelf or lip at the bottom then you can use a fine toothed file to flatten the pads and remove the sheen at the same time. Once they are flat and clean, make sure they are adjusted properly for rim contact and toe in, as discussed above.
Going down: are your pads diving below the rim
Get to the rim of the problem
Isopropyl alcohol aka: Rubbing Alcohol, is just what the doctor ordered (figuratively of course, there are no doctors at Axiom) for cleaning your rims.