uoficowboy

I have an '07 Jamis Aurora that has served me really well. The only problem I've had with it is the brakes - they've just been troublesome since I got the bike. Right now the front brakes are screeching when I brake with them. I pulled the pads off and noticed that they had some bits of metal embedded in them. I removed those with a knife and reinstalled them. The screech seems to be quieter now but definitely still there.

I noticed that they were not made of the material that I think most brake pads are made of. I think of most brake pads as being essentially rubber. These were quite hard as if they were half carbon and half rubber. I believe they are these: Amazon.com : Shimano M70R2 Severe Condition V-brake Pads Pair : Bike Brake Pad Inserts : Sports & Outdoors since on the inside they say "Shimano severe condition use". I also noticed that my rims have a definite groove in them that I'm assuming is from my brakes over the years. Note that these pads are not original - I think I installed them about a year ago.

Does anything sound worrisome here? I should mention that, after doing some adjusting today, I can pretty much stop on a dime. So they absolutely are effective. But they're also noisy. And I'm worried that they could be eating through my rims.

dabac

The groove MIGHT be a wear indicator line. When the side of the rim has worn smooth it's on the way of splitting open and needs to be replaced.
Or you've managed to get something really nasty lodged in the pads.
First line of defense against squeal is to set a proper toe-in.
Severe condition pads are usually SOFTER than average condition pads, to provide sufficiently friction when wet.
But even those will feel really firm to the touch. If they didn't, they'd wear out in miles.

Panthers007

I hate brake-pads that, for all intents & purposes, seem to be made of concrete. Unfortunately many of them do. May I suggest Kool Stops? Take a look...

Kool Stop International - High Performance Bicycle Brake Pads Since 1977

Back in the 1980's a new brand of brake-pad hit the stage. They cost more than the average ones, so they were sort of a cult item. At first. These were the Mathauser brake-pads. Beware of googling these - seems Shimano is now claiming they invented them! That's a big, fat lie. They were made by Scott Mathauser and patented. But here's a set of them:

Scott Mathauser: Cycling | eBay

And they looked like:



A decade or so ago, Scott sold his formula to a new company and it was called Kool Stop. Their pads are made of very similar material. And they are the best. Throw the Shimano concretes' in the trash. Kool Stop's website claims they have been around since 1978, but they can get away with that as they bought the rights from Scott.

Andrew R Stewart 

I'll add to Panthers007 good advice that really clean pads and rims compound the squeal problem. A solution i have often used is to stuff some vegetation between the pad and rim then ride the brakes. Wood chips or a clump of dirt work well. This will reduce the friction between the rim and pads which makes the grab and release cycles FAR less. And it's these cycles happening at sooo many times a second that drives the noise. Andy.

fietsbob

Dueling hearsay .. I heard the reverse..

Kool Stop was who molded the pads used for Scott Matthauser's products, as a subcontractor...

they did the same for Magura.

uoficowboy

About getting stuff lodged in the pads - I pulled out a lot of chunks of metal from my pads with a knife. Nothing huge though - most were a mm or two long at most. That absolutely has cut down on the noise. Is that normal to find chunks of metal embedded in pads?

I forgot about toe in - right now my brakes are hitting pretty flat. I think toe in means that the front of the pads (ie the end of the pad closer to the front of the bicycle) hits the rim before the back of the pad, right?

dabac

Dunno about chunks, but flakes, sure.
And yes, toe-in means the pads alignment should have just a hint of snowplow over them.

uoficowboy

Hmm I think my last pads were Kool Stop pads. I think they were red - does the color mean anything? I can't remember how I chose these Shimano ones - I think they may have been the ones that fit at REI

Out of curiosity - why do you suggest switching immediately to the Kool Stops? I mean, my stopping ability is a non issue. The squeal I'm working on, but may be able to improve. Are these pads potentially damaging my rims?

Andrew R Stewart 

We see pads with "chunk' often. Actually the chunk is a build up of tiny shavings from the rim. A piece of grit or whatever gets in-bedded into the pad and then starts to shave down the rim. The tiny chips collect together at the spot of the original offending bit. This collection is pretty much a "chunk".

The worst pads for this were the black Campy NR ones back in the 1970s. With the softer alloy used in rims then I learned to bring my Swiss Army Knife to dig out these chunks. In fact it is this issue that drove me to Scott Matthauser pads to begin with. Still have a bunch of "C" inserts on my shelves. Andy.