Bicycle Mechanics - when I brake I hear a sound.

When I apply my front or rrear brake I hear a sound, I have been trying to find out if mytires are not true/or the surface of the rims is not smoth, last night I change the brake pads on the rear and front tire the sound that I was hearing disappear, but now I am stuck w/ a not so worn out brake pads, but then I don't hear the stupid sound

If your old pads seemed to be the only ones causing the problem, they might be imbedded with sand/gravel/road grime. If they sat around on the bike for a while, like if you took a break from riding, then they might have gotten brittle. If it was my opinion, and based on the information you gave, I would say your old pads either didn't jive right with the rims or they were covered in too much mud or road grime. You could try sanding them down a little or rubbing them with a cloth to try to clean them to see if they work better without making noise.

What sound do you hear? Different sounds indicate different maintenance needs.

If you have aluminum rims, you might have brake dust accumulated on your rims (assuming we are talking rim brakes here, and not disc brakes).

Get some brake cleaner or wheel cleaner from the automotive store. Wheel cleaners that remove brake dust work pretty well. They are convenient and work well - stuff like wheel foam. Just make sure it removes brake dust.

I know that you are savvy enough to know that glazed brake pads squeek, so I will assume that it might be the rims.

kinda off the subject a little here, but I bought my little(well, not so little anymore) girl a wally world MTB, and the day after giving it to her, she come back complaining of a chirping or chattering sound when she braked. After test driving it, I noticed the 20 coats of paint they put on the wheel was the culprit. So I sat down with a small wire wheel and buffed all the paint off the braking surface on both wheels, kinda like breaking it in for the first 50 miles or so. It fixed the prob, but now it rusts like crazy when she don't ride it for a day or so, anyone know how to fix this prob. I onle did this after looking at my DS bike, and noticed that they were completely devoid of paint on the brake surface, but I have rode my bike countless miles too. And mine don't rust at all. And yes, we keep our bikes indoors in the garage.

I am guessing the problem is your wheels are aluminum, here cheap wally-world bike has steel rims. My wife got a cheap wally Mongoose when we started dating. The thing weighs like 40 lbs. I have no point to the last point, just mentioning.

As for stopping the rust, it would be a toss up. All I can see is new rims (probably 24") which would cost more than the bike did. New paint, but chatter problem, and would wear off or something like WD-40 on a rag rubbed around the rims to put a thin layer of oil down.

Originally posted by jon-w9
something like WD-40 on a rag rubbed around the rims to put a thin layer of oil down.

Oops, good thinking, but bad advice, jon-w9.

Don't put oil or any other lubricant on your brake pads or on the rims. If the brakes don't work (because you lubricated the brake surface), the wheels may rust anyway - in the junkyard along with all the other twisted metal.

Lubrication on the rims of a bicycle is like cutting the brake lines on an automobile.

Originally posted by orguasch
When I apply my front or rrear brake I hear a sound, I have been trying to find out if mytires are not true/or the surface of the rims is not smoth, last night I change the brake pads on the rear and front tire the sound that I was hearing disappear, but now I am stuck w/ a not so worn out brake pads, but then I don't hear the stupid sound
What kind of sound did it make? My Specialized Sirrus squeaks when I stop short. Under normal breaking, it's fine, but when I have to make an emergency stop (but do lock up the tires) I hear this real annoying squeaking noise. Is this normal? My rims are "Mavic CXP-21" <----not sure if it makes a difference or not.

Believe it or not, common Hairspray is a VERY good solvent to clean road film from the brake pads and rims. Loss of proper "toe- in" is often the culprit as well. As mentioned above, grit in the pads can be the problem too. Sanding the rims can be a solution but is usually uneccesary- Why lose part of your braking surface, when cleaning or adjustment and solve the problem.. of course if all else fails, What the *&%$ did I do with that @#%*wet/dry sandpaper??
A light sanding of the pads can help too!

Ride Quietly; Hufffing, puffing, gasping etc. allowed
Pat

Brakes can act strange with even the slightest loss of adjustment.

A tiny amount of toe in adjustment often times rids the sound for me.

When I started using a Burley trailer on my hybrid, the added weight really made my brakes hard to figure out. The only way to stop the chatter and squeal was to afix a couple of boosters. (Nasbar plastic cheapos at $5.00 ea. :) )

Originally posted by Cadd

What kind of sound did it make? My Specialized Sirrus squeaks when I stop short. Under normal breaking, it's fine, but when I have to make an emergency stop (but do lock up the tires) I hear this real annoying squeaking noise. Is this normal? My rims are "Mavic CXP-21" <----not sure if it makes a difference or not.

EDIT: (DO NOT LOCK UP THE TIRES)

What does "toe-in" or "proper toe" mean?

'Toe-in' is angling the pads so that the front edge hits the rim first.

http://www.parktool.com/images/repair_help/pad_toe_line.jpg

You can read detailed setup tips for different types of brakes here:

http://www.parktool.com/repair_help/FAQindex.shtml#brakes

Thx for the site. I'm sure it'll come in handy for me. :beer:

I don't like chemically cleaning rims or brake pads. Three items:
Scotchbrite pad, flat coarse file or piece of emery cloth, and dental pick. Clean the rim flats with Scotchbrite until all you see is metal without streaks of black rubber from brake pads. Use the pick to take any chips of rim metal or other debris out of the brake pads, then file or sand the glazed areas off of the pads.