Mountain Biking - noisy disc break

I have an 04 Specialized Stumpjumper FSR with M525 brakes and XT rotors -

The front break does not really even work- you get on it really hard and it just screams out a horrible loud squeek... I tried everything... changed the pads - cleaned everthing - the rotor seams to be straight... and it is still the same...

I don't want to buy new breaks if I can help it...

What can I do?

its spelled brake.
What are you cleaning this stuff with? Isopropyl alcohol is best. Are you using these in wet conditions? Any disc brake will squeak in wet

take them off, and send them to me.

my rim brakes squeaked when they were wet :(

yeah, but rim brakes are inferior to disks.... period!

YEAH BUT THEYRE OLD SCHOOL
AND THUS

SUPER AWESOME

disc brakes also scare me what with the technology involved and all. They also add bling to my bike and I'm afraid I will attract thieves! :D:D:D:D

disc brakes are super easy to work/ adjust.... there is nothing to be scared of exsept your rim brakes *said in a spooky voice*

its spelled brake.


i was wondering if it was just me, but seems everyone spells it wrong! its either, disc break, disk brake, disk break.. never Disc Brake.....

Right, Brake... OK

:o

I used windex to clean the rotor, and sanded the newly replaced pads with 250 grit sand paper ... and it is still the same - it is like the pads are just getting glazed... it does the same thing even to a new set of pads right out of the package... I keep thinking that there is something wrong with the rotor, but I have been puting off replacing it, the bike probably has less than 20 hours riding on it... I moved shortly after I purchased the bike, otherwise I would have just taken it back to the dealer...

Right, Brake... OK

:o

I used windex to clean the rotor, and sanded the newly replaced pads with 250 grit sand paper ... and it is still the same - it is like the pads are just getting glazed... it does the same thing even to a new set of pads right out of the package... I keep thinking that there is something wrong with the rotor, but I have been puting off replacing it, the bike probably has less than 20 hours riding on it... I moved shortly after I purchased the bike, otherwise I would have just taken it back to the dealer...
Never use Windex to clean rotors! You should ONLY use denatured alcohol to clean them. You've contaminated your pads. You have a couple of options.

Buy new pads
Try to cook the old ones usually this involves a blowtorch or your wife's oven. It's probably safer (for everyone) if you spent the $30 on new pads

Don't drag his wife's oven into this.

Don't drag his wife's oven into this.
Yeah I probably shouldn't have mentioned that, but windex? :rolleyes:

Never use Windex to clean rotors! You should ONLY use denatured alcohol to clean them. You've contaminated your pads. You have a couple of options.

Buy new pads
Try to cook the old ones usually this involves a blowtorch or your wife's oven. It's probably safer (for everyone) if you spent the $30 on new pads


HA! Wife's oven

+1 for something I laughed at

Really now, if it squeaks, just oil it. :D

Really now, if it squeaks, just oil it. :D
I KNEW someone would say that! Doesn't make it right, but I knew someone would say that

When we first took our tandem out, at every stop, people would come over to have a closer look. You'd be amazed (or not) at how many guys felt they had to put their damn grubby, greasy, oily fingerprints on my titanium rotors! Yeah, they looked cool, and were really expensive. Why the hell do you need to touch them?! They're a braking surface!

When we first took our tandem out, at every stop, people would come over to have a closer look. You'd be amazed (or not) at how many guys felt they had to put their damn grubby, greasy, oily fingerprints on my titanium rotors! Yeah, they looked cool, and were really expensive. Why the hell do you need to touch them?! They're a braking surface!
People are stupid like that. Of course watching someone do that after a long downhill would just about be worth cleaning the scorched flesh off

I wish. They were Ti, so they never stayed warm for very long. But why did they feel the need to touch them? Geez!!

I wish. They were Ti, so they never stayed warm for very long. But why did they feel the need to touch them? Geez!!

Looking at Ti rotors does not justify its beauty.

Everyone wants to touch it first hand and be able to say "I touched a ti rotor"

Looking at Ti rotors does not justify its beauty.

Everyone wants to touch it first hand and be able to say "I touched a ti rotor"

Hey, they can touch the damn frame! That's a big hunk of Ti too. I just wish people would keep their grubby digits off my braking surface. Anyhoo, as I've posted 100 times before, the rotors were crap anyway. Maybe I had so many issues with them because of all the morons that had to touch them.

Windex leaves residue, always fun. Thats probably why your brakes are screaming like a school girl who has just seen a frog

Think of Ti rotors as a hot naked chic laying in your bed; what are you going to do?

yeah, but rim brakes are inferior to disks.... period!

Explain. Except for immediate stopping power, rim brakes are cheaper, lighter and have less parts to worry about installing, breaking, replacing. Disc brakes are good for their immediate stopping power and thats about it.

Explain. Except for immediate stopping power, rim brakes are cheaper, lighter and have less parts to worry about installing, breaking, replacing. Disc brakes are good for their immediate stopping power and thats about it.
Oh you forgot about the whole stopping in rain/mud/slush, all kinds of other good crap part....

Explain. Except for immediate stopping power, rim brakes are cheaper, lighter and have less parts to worry about installing, breaking, replacing. Disc brakes are good for their immediate stopping power and thats about it.

I was once like you; I bought disc brakes and now I am not.

They are easier to adjust than vees. They work better, in wet and dry. The pads last longer too. They do weigh more and after using both that is the only down side.

Chics dig rotors..........I got mine because I got into MTB on the eastcoast in a valley, rotors are a MUST most of the places we ride, just because it is just so rainy here, so we always snicker whenever a new guy comes and has his intro ride with vees, cause we all know he will loose all braking, and hit somethin, THE at the bottom he will want to try someones hydros, start pedalling, brake....and flip over.......its just how it worx, I did it, and all the guys I ride with did it, its only a matter of time :D

Explain. Except for immediate stopping power, rim brakes are cheaper, lighter and have less parts to worry about installing, breaking, replacing. Disc brakes are good for their immediate stopping power and thats about it.


You are so right. Come for a ride in the bush on my tandem. We'll take off the discs and just run some V brakes.

ha, you know I thought of that before. All of a sudden I was like, woah, if you wanted to kill someone, you could just put oil on their rotors.

its spelled brake.
What are you cleaning this stuff with? Isopropyl alcohol is best. Are you using these in wet conditions? Any disc brake will squeak in wet

Isopropyl Alcohol doesn't always work. If the pads are contaminated with oil, you will need to bring out the "big guns". Denatured alcohol with break down that oil. You will also need to treat the rotor with denatured alcohol.

BTW, when you have disc brakes, consider that the end of using spray on lubricants. The disc rotors are just too close to the chain.

yeah, but rim brakes are inferior to disks.... period!

I'm a fan of disc brakes. But a disc brake is not always better than a rim. This is especially true if you have cheapo disc brakes that are poorly maintained.

In principle though, a good disc brake properly maintained will stop better in more conditions than rim brakes.

In 3 years, I don't think you'll be able to buy a mountain bike with rim brakes. We'll have to see about road bikes. Only touring and cross bikes seem to be shipping with the Avid BB7 Road.

Explain. Except for immediate stopping power, rim brakes are cheaper, lighter and have less parts to worry about installing, breaking, replacing. Disc brakes are good for their immediate stopping power and thats about it.

Lighter:
In most cases, yes you have a point here.

Cheaper:
Not for long. Economies of scale are bringing disc brakes into line with caliper brake prices.

Less parts:
I'm not sure about this. A brake is a cable anchor, a lever arm, a caliper, two pads and a braking surface. The difference in this regard is that the braking surface is integrated into the hub instead of the rim. The advantage here is that you can replace the disc rotor without having to undo all your spokes and re-rebuilding your wheel.

If you count all the washers and nuts in a rim caliper, I'll bet you'll find the part count is similar to that of a simple disc caliper.

Immediate stopping power:
Yes, they do stop faster. They also have a tendency of not melting so easily when going downhill (nobody does downhill on rim brakes). They also work in rain and mud.

MY POINTS:

Calibration:
Lets face it rim brakes are a PAIN IN THE ASS to calibrate. They require special tools (4th, 5th, 6th hand tools) to get the job done right. Centerpull, cantilever, v-brakes, they're ALL a pain in the ass!!!

Replacing disc pads is EASY. Replacing rim pads is a nightmare. ADJUSTING them is a nightmare. Adjusting discs is simple process of loosening the anchor bolts, locking down on the brakes, tightening the
anchor bolts, than backing off on the pads.

Robustness:
Disc brakes don't become impossible to operate when the wheel goes out of true. Disc brakes NEVER rip wear the rims or rip open tires.


The rim brake IS on it's way out. The roadies will cling stubbornly to their rim brakes for a while, but the disc manufacturers will keep refining their products to the point where they'll be as light as caliper systems. First the tandems, tourers and cyclo-crossers will all go disc, than the roadies will finally accept them.

Hey, they can touch the damn frame! That's a big hunk of Ti too. I just wish people would keep their grubby digits off my braking surface. Anyhoo, as I've posted 100 times before, the rotors were crap anyway. Maybe I had so many issues with them because of all the morons that had to touch them.

Maybe next time, you can bring cotton gloves and tell them they can touch them ONLY if they're wearing those gloves.

It's natural to want to touch things.

Either that, or you could wipe down the rotors in denatured alcohol BEFORE people get close to the bike ;-)

Lighter:
In most cases, yes you have a point here.

Cheaper:
Not for long. Economies of scale are bringing disc brakes into line with caliper brake prices.

Less parts:
I'm not sure about this. A brake is a cable anchor, a lever arm, a caliper, two pads and a braking surface. The difference in this regard is that the braking surface is integrated into the hub instead of the rim. The advantage here is that you can replace the disc rotor without having to undo all your spokes and re-rebuilding your wheel.

If you count all the washers and nuts in a rim caliper, I'll bet you'll find the part count is similar to that of a simple disc caliper.

Immediate stopping power:
Yes, they do stop faster. They also have a tendency of not melting so easily when going downhill (nobody does downhill on rim brakes). They also work in rain and mud.

MY POINTS:

Calibration:
Lets face it rim brakes are a PAIN IN THE ASS to calibrate. They require special tools (4th, 5th, 6th hand tools) to get the job done right. Centerpull, cantilever, v-brakes, they're ALL a pain in the ass!!!

Replacing disc pads is EASY. Replacing rim pads is a nightmare. ADJUSTING them is a nightmare. Adjusting discs is simple process of loosening the anchor bolts, locking down on the brakes, tightening the
anchor bolts, than backing off on the pads.

Robustness:
Disc brakes don't become impossible to operate when the wheel goes out of true. Disc brakes NEVER rip wear the rims or rip open tires.


The rim brake IS on it's way out. The roadies will cling stubbornly to their rim brakes for a while, but the disc manufacturers will keep refining their products to the point where they'll be as light as caliper systems. First the tandems, tourers and cyclo-crossers will all go disc, than the roadies will finally accept them.

I agree with you except for the road bike part. The amount of stopping power out weighs the traction a road tire can achieve. It is easy enough to lock-up a wheel now much less with discs.

I would hate to see what a disc brake would do to a road rim. The amount of force excerted causes(d) really light xc rims to brake, especially in the past. And really could disc brakes ever be as light as a roadie setup. I just don't see discs moving over to road bikes. They might be clinging to the past but with some good reason

I would hate to see what a disc brake would do to a road rim. The amount of force excerted causes(d) really light xc rims to brake, especially in the past. And really could disc brakes ever be as light as a roadie setup. I just don't see discs moving over to road bikes. They might be clinging to the past but with some good reason


Yeah weight is of course a factor; wheel weight at that. I don't think they are clinging to the past in any way. Road bikes are just moving in a totally different direction than mountain.

Why are discs better than rim brakes?

The difference is friction. Friction is of course the force acting against the momentum. Friction under all circumstances will be greater in a disc system than a rim system. Not even ceramic rims and their pads can compare to the sustainable friction of a disc system. Not to mention the effects of inclement conditions on rim brakes.

Let's start by taking a look at the physics involved. There's a law of physics that states how an object in motion has a certain amount of energy due to its momentum. This energy is called kinetic energy. In order for this object in motion to stop or slow down, it must lose some or all of its kinetic energy. It does this by converting the kinetic energy to heat.

It's pretty simple. At your wheel you have a metal disc and a set of friction pads. The pads squeeze or push onto the metal. When this happens, you create friction. Friction generates heat, of course. Since the wheel is turning, then the kinetic energy of your momentum is converted to heat at this point and discharged harmlessly into the atmosphere (with a slight loss of pad material), and your bike slows down. The faster it is going, the more heat is needed to stop it. The more pressure you apply to the pads, the faster it can discharge the kinetic energy.

Adding a larger disc aids in the discharge of the heat generated the increased surface area allows heat to dissipate more quickly

Rim brakes work well, but they have a hard time shedding heat well enough to prevent fade when used really hard. Brake fade occurs when the brake overheats dramatically; braking power is vastly reduced.
Facts

Disc brakes handle heat load and dissipation better than calipers.
They don't transfer the heat generated directly to the rim, like calipers.
Disc rotors are MUCH cheaper to replace than an entire rim (as low as $15). As far as being able to lock a wheel: yes you can lock a wheel much easier with a disc than you can a caliper of any type, however if your brakes are PROPERLY setup, you also have greater modulation with less effort than any caliper system ever invented.

Do I have V brakes on my road only commuter? Yes. Due, in no small part, to the fact that both my frame and fork are not disc compatible. As I plan on eventually (after my shock upgrade on the trail bike) swapping out the fork on my commuter for a rigid model that has disc tabs I will not be without the added all conditions stopping power of discs for much longer. It is also possible that I may even just get a fork with V-brake bosses as the current setup is adequate for most everything I encounter while commuting in Florida, but it's funny how things can change.


I reposted my post from an earlier discussion on the matter

GEt them rebled, clean the rotors get new pads re adjust your calipers make sure your master cylinder's adjustment screw isn't outta wack.

Hi, I have a mountain bike, its the IronHorse Warrior 21.5" and i have a really messed up back disc brake. Theres always hittage with the brakes and there is alot of squeeking, what can i do. Ive tried 99% alcohol and it didnt do anything. Any suggestions?

Use the search function of the forums, rather than reopening an old thread. I'm sure it's already been posted how to replace a bent rotor.

(nobody does downhill on rim brakes)
I did. ;) And I glazed the pads... and at the end of 8 runs on the black, my brakes smelt of something burning. :lol: Anyway, it's not a good idea, to say the least.