1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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Results 1 to 14 of 14
  1. #1
    Australia = phun
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    Can't disc brake problems be fixed by changing brake pads?

    Squealing, loss of power, overheating - can't they all be changed by a bit of adjustment and changing brakepad? The different shape/design/material/position can change the problems for the better, can't they?

  2. #2
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    Maybe...

    maybe not. Pad material can make a difference in noise, and they can make a difference in power. However over heating is usually not affected by pad material. Some pad materials do resist heat build up better, but their usually that pads that are more prone to squeal. As in organic pads tend to be quieter, but are easier to over heat, metallic pads resist heat better but are louder and more prone to squeal.

    Over heating is usually due to over use of the brakes. Heating up a disc brake can't be helped. The energy of motion is reduced by converting it to heat energy in a brake. There's no way around it. If you are over heating your brakes you have one of two options. Use them less, i.e. take look at your braking technique. Riding the brakes on a downhill will over heat them. Use the front and rear brake when you apply them, etc. If you have good technique but are still over heating the brakes then something needs to be changed. Usually going to a larger size rotor will help. Different pads also might if you are using organic pads shift to metallics. If that still doesn't solve the problem then a larger heavier duty brake may be in order. Unfortunately the brake pads for a given brand/model of brake will be the same shape and size no matter who makes it.

    As far as noise goes, there are a lot of factors that can cause brakes to make noise. The primary cause is set up. If the brake pads aren't hitting the rotors squarely they are more likely to make noise. If fasteners aren't properly and evenly torqued brakes may make noise. Other factors are pad glazing due to high heat, pad or rotor contamination, weather conditions, brake or pad design, the way you hold your mouth when you apply the brakes. Okay maybe not that last one, but there are allot of reasons that a brake can be loud.

    A loss of power is usually associated with three things, worn out pads, glazed pads, or contaminated pads and/or rotor. Glazing usually happens when the pads have been over heated. It's simply that you've gotten the pads hot enough to slightly melt the boding agent that holds the pad material together. It creates a glassy surface that doesn't bite well and reduces power. Glazing can be cured by lightly sanding the pads to remove the glaze, or simply replacing the pads. Solving worn out pads is simple and obvious, replace the pads. And contaminated pads and rotor is pretty easy as well. You can try baking the pads to remove contaminants, usually some sort of lube that you've gotten a little careless with. Or you can replace the pads. But you'll need to attend to the rotor as well. Pad contamination usually contaminates the rotors as well. If you don't clean the rotors you'll simply recontaminate you revived or new pads. Simple rotor cleaning simply involves a soft lint free rag and some rubbing alcohol. However the most effective method is to lightly sand each rotor on both sides until the burnish where the pads make contact is removed, the clean with alcohol. This will require that the brakes be bedded in again. But will usually solve loss of power issues due to contamination.

    It should also be noted that any one or any combination of the above can cause squeal, loss of power, and over heating. As an example, glazed pads don't bite as hard as they should. This causes you to pull harder on the lever for longer to get the bike to slow down. This causes overheating as you are staying on the brakes harder and longer. And hot brakes tend to squeal in most instances. Also glazed pads tend to squeal as well. The same can be said for any of the other problems as well.

    So, yeah your problems may be solved by simply replacing the pads. But to be certain, you have to find the cause of your problem. There are too many reasons that you could be experiencing squeal, loss of power and overheating to simply say yeah replacing the pads will take care of it. I mean if your braking technique is bad or you're using too small of a rotor for your weight/riding style, then you're just going to over heat the new pads the same way, glaze them over and be right back where you started from.

    So figure out why this is happening. Then you can figure out a solution that will work and will last.

    Good Dirt

    Oh and just a note. Knowing what brand and model of brake we're talking about here would help allot.
    Last edited by Squash; 10-28-2010 at 06:13 AM.
    "I do whatever my Rice Cripsies tell me to!"

  3. #3
    Australia = phun
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    I'm just asking a general question, not that I have a faulty brake. Thx

  4. #4
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    Thanks for the useful info. I need some more advice. I think might have cooked my front rotor and/or pads on a long downhill ride. I'm not sure though, because I've definitely cooked them worse before, and had no ill effects once they cooled down.

    During the ride, I noticed a lack of power, but figured it was because they were heating up. But the next day in my garage I was doing some maintenance and noticed the front brake had almost no stopping power. There's just no friction. The lever pull feels the same as it always does, but I can still turn the wheel with the brake fully applied. I've tried the following to fix it:
    -sanded rotor, sanded pads, 20-30 stops to bed in, still no stopping power
    -sanded rotor, tried old mostly used up pads, 20-30 stops to bed in, still no stopping power

    About the replace rotor and pads, but want to make sure I'm not missing something first.

    Any advice?

  5. #5
    Fat-tired Roadie
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    Does the lever feel weird? Did the pads look weird? What brakes do you have?
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  6. #6
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    Lever feels same as always. Pads did look glazed, but I think that happened from trying to stop after the brake had lost power. But that's why I sanded the pads anyway. This is also why I tried the old pads. They looked normal.

    Elixer 9 Trail brakes.

  7. #7
    Fat-tired Roadie
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    Odd. Front and rear rotors look different?
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  8. #8
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    No, they both look the same. They both got some black streaks on them after I did a day of downhill a few weeks ago, but were still working fine until the last few days. When the front one stopped working, I sanded it until the black streaks were gone.

  9. #9
    Fat-tired Roadie
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    Interesting. Do the black streaks reappear when you try to bed in each time?
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  10. #10
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    No, the rotors are just shiny, like you'd expect. However, they're not evenly shiny all around, probably because I didn't sand them perfectly evenly. Like near the edges, and around the edges of the holes, they're a little duller looking.

    Could this be the problem?

  11. #11
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    This is why I always ride up hill!

  12. #12
    Fat-tired Roadie
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    Sounds like they're maybe not as flat as they should be anymore. Try swapping rotors, maybe? Since your back brake is okay, if I'm right, it'll make your front brake work again, while your back brake takes a turn sucking.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  13. #13
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    Got new rotors and new pads, then came to the conclusion that the calipers weren't closing all the way, even though the lever pull felt normal. Took it to the LBS and they confirmed my suspicion. They said there might be a blockage somewhere in the line or cylinder.

    WOW, WHAT A PITA! Now realizing I probably didn't even need to go through all the sanding and replacing parts!

  14. #14
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    Update: I'm getting new front and rear brakes from Avid under warranty! Apparently this was a known problem. Sweet!

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