mcavana

Got my wifes new bike today. It is a Felt cafe 7.

So far this purchase isn't going well. Wife test drove it and all was good except for a loud front squeeky brake. Told mechanic that break pad prob wasn't on perfect and asked him to fix it. Well, an hour later, it was determined that there must be something wrong with brake itself.

Now my mechanic is no dummy! He tried everything... and tested bike himself several times. He adjusted pads a couple times, no luck. Pads set perfect, still squeels. He put an extra washer on the mounting screw and made it more secure. still squeeks. He greased all the hardware... still squeeks. He changed out the brake pads and started over. still squeeks. He cleaned the rim with acetone to make sure nothing was on it... still squeeks. Wheel perfectly straight.

Well, wife was excited to ride it and back brake worked fine... and it was 10 minutes to closing time. I told the mechanic I would mess with it and we agreed that if it didn't get better he would just order a new brake from factory and replace it under warranty.

So we took it home and did short ride. Got back to house and I tried myself to get the squeek to quit. Spent an hour on it! Did everything mechanic did... ALSO removed back brakes and put them on the front....

The front STILL SQUEEKS?!!!

WTF?! How is this happening? Trust me, I know how to install brake pads. I have been riding for years. It isn't one of those soft high pitch irritating squeeks... It is a loud ass squeel.

Are the welded on brake mounts defective or out of line? Is there something wrong with the wheel? It can't be the brake itself if moving the rear brakes to the front didn't fix it. Is frame bad?

Then to top things off in making sure the pads werent resting on the rim, I spun the rear wheel... and noticed a weird noise coming out of the rear hub. It is like when it gets to a certain part of the rotation it makes a soft crunching or grinding noise... WTF is that?! does that mean hub isn't right or is loose or something?

FBinNY 

It helps to understand the mechanism that cause the squeak, which is similar to why new chalk can squeal on a blackboard.

When you apply the brake to a moving rim, the motion of the rim pulls the shoes forward. Since the mounting to the fork is well behind the shoe, the forward motion causes the shoe to twist to a toe out, heel in angle. You can see this if you gently apply the brake and push the bike forward.

The twisting action digs the heel in making the problem worse until it hits a critical point and slips back. The standard cure is to to the shoes in a bit so that the twisting action brings them flat, but no more.

Canti and V-brakes can be very susceptible to this process because of play at the pivot, bit also because the brake studs are on the front of the blades, and reaction forces of applying the brake pushes the front out, adding to the twisting. Sometimes the cure is more toe-in when you mount the shoes, but I've seen brakes where you'd need a ridiculous amount of toe-in to compensate. These usually benefit from a "brake booster" horseshoe which keeps the studs from spreading.

Before you pull all your hair out, try this trick from my toolbox. Remove the wheel and use a file to break the rear corner of the shoes. Ideally you want to file a curved "ski tip" covering the rear 4-6mm of each shoe. Without a hard corner to dig in, the harmonic process is less likely to start.

mrrabbit 

1. Front brake pads need to be toed in...assuming these are old-school style regular caliper brakes. Front of pads will be 1-2mm closer to rim than rear of pads. This is accomplished by either minor bending of old-style caliper arms - or simply positioning the pads using their built in pivot washers.

2. Have the mechanic adjust the rear cones on the hub. Make sure he does it with the wheel OFF THE BIKE! Also have him double check to make sure the drive side cones/locknuts on front and rear hubs are "locked" tight.

Solid axle cones should have a slight grind...

QR axle cones should have no-grind to very slight play BEFORE quick release is closed.

=8-)

rdtompki

No guarantee, but OEM pads leave a lot to be desired. Easiest high probability fix is to change the pads. Koolstop Salmons worked on our tandem.

onespeedbiker

I seriously don't think the brake is to blame. I checked out your bike and I see it has Tektro V brakes and an aluminum fork. Toeing in can help, but for some reason toeing out a little sometimes will stop squealing ( I have no idea why this would work but it sometimes does). A brake booster should be on your A list along with taking some emery cloth and roughing up the brake surface. I rarely recommend switching brake pads unless they are the OEM pads on an inexpensive bike and the rims are cheap (sorry; what are ribbed aluminum rims anyway?); you said your mechanic changed the brake pads, but you did not say what he replaced the OEM pads with (or if replaced them with the same pads). Many OEM pads are very hard so they will last a long time, but this can create a vibration that leads to the squealing (especially on non-machined rims), so make sure you put on some softer pads; the Kool Stop Salmon colored are known to be soft and are quite popular.

PaintedSpokes

check the rim. while not likely with a new bike, the rim may be concaved. this tends to happen with bikes that have been used to years as the pressure form the pads bends the actual braking surface inwards. if the rim is defective, this can cause unstoppable noises. and I would try harder pads, not softer. while I've only had this problem with bmx running chrome rims, I've found that softer compounds (clear, gum, or red in bmx) are a lot grabbier than regular black pads, so they cause vibration on the rim. I agree koolstop makes amazing pads, but try a black compound. and if you can get another rim on there for a test ride, you may find that solves it.

fietsbob

Run by the shop and we will check it over .

Oh you are on the opposite coast ... N/M

gets the pedestrians out of the way, don't it?

SurlyLaika

I have the same problem on my front wheel. The LBS rebuilt the wheel after I destroyed the rim in an accident. (the rim was caught in a gap in the concrete) I think it always squealed, even before the accident, but no matter what I do now, it always squeals when I brake hard. And I've tried the same methods. Cleaning the rims, toeing the brake pads, etc. Not even Kool-Stop Salmons helped. Changing the brakes from Tektro Onyx to Shimano BR-R550 helped some, though. You shouldn't have to replace the brakes on a new bike but maybe an upgrade is something to consider.


The LBS adjusted my brakes and got it to at least not be so temperamental. It'll make a little noise if I press down gently. With the help of the perfect rear brake, this something I can live with, but if I slam hard on the front brake, it makes the absolute loudest, ugliest noise I have ever heard. I think the front wheel just sucks, but who knows?

Does yours make noise even when you brake gently?

mrrabbit 

Any thing to test...

Try popping in a wheel that has CNC sidewalls. A mechanic I know says that oftentimes CNC sidewalls will make cheap OEM brakes "shut up" so to speak.

=8-)