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  1. #1
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    Road Disc Brake Squeal

    On hard descents that require lots of braking, my discs are HOWLING. Shimano RS-685 levers and calipers, 160 mm Shimano RT-86 Ice Tech rotors front and back. Brakes are fine and quiet on normal downhills that only require braking a few seconds before a curve, maybe taking 10-15 mph off the top for safe cornering. I rode some beastly hills last couple days, sustained grades 12%+ with very few curves. 45+ mph happens pretty fast once you're off the brakes. I had to slow from 52 down to 15 to take a leaf-strewn switchback, then another few sections of hard braking scrubbing off 20+ mph each time within the next minute. The last part down to an intersection was like -17% for a few hundred yards, and it was HOWLING the whole time. I could smell my brakes. What gives? I need to true my rotors now because they warped a bit and now hit the pads when out of the saddle. Do I need to do any sort of maintenance to the brake pads themselves to help with any of this?

  2. #2
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    your pads are glazed or contaminated.

  3. #3
    Forever a Student
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    I hear that blow torches work well.
    use a torque wrench

  4. #4
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    You can smell the brakes? That can't be good. Try pumping the brakes instead of dragging them. It let's the brakes cool between applications. Also, you may have cooked the pads, indicated also by the warped rotors. Change them out. Are better pads available?

  5. #5
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    Another nail in the coffin for disc brakes. :-P

    A fun hearted jab at my brothers who no doubt are 'stopping in' from the current rim versus disc thread. I would say everybody who has owned a disc brake bike has experienced the dreaded death squeal. Its kind of like the back up alarm on a Hi-Lo. ;-D

  6. #6
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    Quote Originally Posted by mfdemicco View Post
    You can smell the brakes? That can't be good. Try pumping the brakes instead of dragging them. It let's the brakes cool between applications. Also, you may have cooked the pads, indicated also by the warped rotors. Change them out. Are better pads available?
    Yup, in other words, can you smell what the Rock is cooking?

    Pump the brakes? Hmmmm, never have to do that with rim brakes. ;-)
    Last edited by 11spd; 2 Weeks Ago at 09:49 AM.

  7. #7
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    Quote Originally Posted by MMsRepBike View Post
    I hear that blow torches work well.
    Good way to cook the fluid to a low boil. I like it when a plan comes together.

  8. #8
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    Quote Originally Posted by 11spd View Post
    Yup, in other words, can you smell what the Rock is cooking?

    Pump the brakes? Hmmmm, never have to do that with rim brakes. ;-)
    These are hills that I wouldn't even try with my rim brakes. I went down a similar one right before I got this bike, and I was white-knuckling the brake levers and still moving 40+ mph and not slowing near fast enough for my comfort. Slowing down from 65+ mph is hard stuff! I sprinkled a couple drops of water on my rims after that and they flash-boiled into a puff of steam. Similarly, trying to pump the brakes on a -18% grade with wet leaves on it is not something I feel safe doing. I'll have to try to remove the pads to see what's going on with them- never done it before, and I have a big ride tomorrow, so I don't want to mess up my bike tonight...

  9. #9
    Adorable Furry Hombre
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    It is a Saturday, I'd take it by a shop. Long-range internet guesses will take longer and be less effective.

    Usually this ends up being a pad/rotor contamination issue. Given your riding, the pads should be bedded in by now.
    "Refreshingly Unconcerned With The Vulgar Exigencies Of Veracity "

  10. #10
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    Quote Originally Posted by TDFbound View Post
    These are hills that I wouldn't even try with my rim brakes. I went down a similar one right before I got this bike, and I was white-knuckling the brake levers and still moving 40+ mph and not slowing near fast enough for my comfort. Slowing down from 65+ mph is hard stuff! I sprinkled a couple drops of water on my rims after that and they flash-boiled into a puff of steam. Similarly, trying to pump the brakes on a -18% grade with wet leaves on it is not something I feel safe doing. I'll have to try to remove the pads to see what's going on with them- never done it before, and I have a big ride tomorrow, so I don't want to mess up my bike tonight...
    yes, better to leave nothing to chance.

  11. #11
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    Quote Originally Posted by Marc View Post
    It is a Saturday, I'd take it by a shop. Long-range internet guesses will take longer and be less effective.

    Usually this ends up being a pad/rotor contamination issue. Given your riding, the pads should be bedded in by now.
    That is the sensible thing to do, but all my shops are so backed up with work orders they aren't even looking at a bike until 3-4 days out. I'll see what I can do with it tonight, and probably call and make an appointment for later in the week- I can't be without my bike for that long!

  12. #12
    Adorable Furry Hombre
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    Quote Originally Posted by TDFbound View Post
    That is the sensible thing to do, but all my shops are so backed up with work orders they aren't even looking at a bike until 3-4 days out. I'll see what I can do with it tonight, and probably call and make an appointment for later in the week- I can't be without my bike for that long!
    Ask the boss wrench what his favorite booze is, bring a 6-pack at close for hanging around late.

    Odds are this is an easy fix.
    "Refreshingly Unconcerned With The Vulgar Exigencies Of Veracity "

  13. #13
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    Quote Originally Posted by TDFbound View Post
    That is the sensible thing to do, but all my shops are so backed up with work orders they aren't even looking at a bike until 3-4 days out. I'll see what I can do with it tonight, and probably call and make an appointment for later in the week- I can't be without my bike for that long!
    or....just wing it and let the chips fall where they may. Just make sure you have your life insurance paid up.

  14. #14
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    disc brakes do tend to howl when they get wet. it does not affect the braking quality/effectiveness

  15. #15
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    Are they metallic or resin pads? Metallic tend to squeal. I have resin pads on mine and they rarely squeal, and when they do it's only for a few seconds and goes away.

    Buy yourself some brake cleaner and some medium grit sandpaper. remove pads. Spray the brake cleaner on the rotor and wipe it down. Maybe repeat a couple of times. Give the pads a bit of a sanding, then clean with brake cleaner. Some people use dish soap. replace the pads then loosen up the caliper bolts and reinsert the rotor with a business card folded around the rotor and in-between the pads. Clamp down and tighten the calipers, then remove the card. This should help. And before the troll 11spd starts spewing nonsense, this takes all of 5 minutes and is less trouble than the trial and error of trying to get the toe and angle right on rim brakes so they don't squeal.

    .

  16. #16
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    Quote Originally Posted by TDFbound View Post
    That is the sensible thing to do, but all my shops are so backed up with work orders they aren't even looking at a bike until 3-4 days out. I'll see what I can do with it tonight, and probably call and make an appointment for later in the week- I can't be without my bike for that long!
    There is only one screw on each set. Pull the little safety retainer and simply remove the screw and pull the pads out. The little spring clip between the pads is self explanatory. There is absolutely nothing to fear.

    I'd probably use a putty knife to open the spacing before removing the pads. You will then be able to squeeze the levers several times and self adjust the brakes when you've completed the sanding/cleaning and replacement.

    When you get it back together and have completed the adjustment lever squeezing, do several decelerations without coming to a stop to bed the pad again. It takes longer to describe the process than to do it.

  17. #17
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    Quote Originally Posted by TDFbound View Post
    I sprinkled a couple drops of water on my rims after that and they flash-boiled into a puff of steam...
    True! Rims heat up as bad as discs if rider rides down the descent on the brakes. I've heard stories of glue melting on tubular rims and the tires rolling off in the switchbacks.

    Its a good idea to not exactly pump, but brake harder in like 3 second spurts rather than riding the brake in white knuckle panic. Yes, have to watch for slick spots on the road.

    Turns are no problem. Brake hard as close to the turn as possible and take an inside line. Don't brake in the turn unless you like to gamble with fate. If done right rider has plenty of road coming out of the turn to choose his line and won't have to brake. Save the pads and rims for another day!
    Last edited by Fredrico; 2 Weeks Ago at 10:49 PM.

  18. #18
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    Quote Originally Posted by 11spd View Post
    or....just wing it and let the chips fall where they may. Just make sure you have your life insurance paid up.
    Not funny at all. Grow up dude. And btw you are out here ruining other threads again. You now have a thread for this. Please take this discussion back to it.
    Last edited by Rashadabd; 2 Weeks Ago at 06:47 AM.
    Every climb has its end, for verily with difficulty there is relief...

  19. #19
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    Quote Originally Posted by Rashadabd View Post
    Not funny at all. Grow up dude. And btw you are out here ruining other threads again. You now have a thread for this. Please take this discussion back to it.
    https://www.youtube.com/watch?v=t0hK1wyrrAU


    https://www.youtube.com/watch?v=HV-e...Y#t=31.2308187

  20. #20
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    I said, I meant it, and in case you can't see it, you are starting to engage in the same behavior that got you kicked off the site as Roadworthy. Take a few steps back and just assess your own posts over the last couple of weeks. Seriously....
    Every climb has its end, for verily with difficulty there is relief...

  21. #21
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    Quote Originally Posted by Rashadabd View Post
    I said, I meant it, and in case you can't see it, you are starting to engage in the same behavior that got you kicked off the site as Roadworthy. Take a few steps back and just assess your own posts over the last couple of weeks. Seriously....
    My posts have been impeccable. I am sorry you are offended. Identifying differences of opinion implicitly and not even overtly by my posts makes you angry which you then display which only lowers the decorum of this forum, upsets others and distracts from the subject being discussed. It is you who should take steps back and reflect on your level of intolerance. It is you who is publically criticizing me which is against forum policy.
    I have never said anything derisive toward you.
    Last edited by 11spd; 2 Weeks Ago at 09:33 AM.

  22. #22
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    Quote Originally Posted by 11spd View Post
    My posts have been impeccable. I am sorry you are offended. You don't know much about cycling and exposing this reality implicitly and not even overtly in my posts makes you angry which you then display which sadly lowers the decorum of this forum. It is you who should take steps back and reflect on your level of intolerance. It is you who is publically criticizing me which is against forum policy.
    I have never said anything derisive toward you.
    You pretty much just proved my point. Do you 11spd. It will all come out in the wash.
    Every climb has its end, for verily with difficulty there is relief...

  23. #23
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    Quote Originally Posted by Rashadabd View Post
    You pretty much just proved my point. Do you 11spd. It will all come out in the wash.
    Always does Rash. But consider working on your intolerance of others...what wars are fought over. Cycling and people that come to this forum are made up of a broad demographic. Many aren't just like you. You need to accept others. For example I accept you and also accept there are many highly intolerant people in the world which some call elitism. You can't control others and you simply make yourself upset and my personal view is this comportment is selfish because your personal attacks lower the decorum on forums such as this. So try to refrain from this behavior to make this a friendlier place to come. A forum such as this should be an escape to enjoy our passion for the sport of cycling in spite of our differences. Cycling should be our common bond and no doubt if we were out on the road and mixing it up it would be.

  24. #24
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    Quote Originally Posted by 11spd View Post
    My posts have been impeccable. I am sorry you are offended. Identifying differences of opinion implicitly and not even overtly by my posts makes you angry which you then display which only lowers the decorum of this forum, upsets others and distracts from the subject being discussed. It is you who should take steps back and reflect on your level of intolerance. It is you who is publically criticizing me which is against forum policy.
    I have never said anything derisive toward you.
    Have you noticed the pattern here? Stop being a putz.
    Get a better saddle: www.kontactbike.com

  25. #25
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    Quote Originally Posted by Kontact View Post
    Have you noticed the pattern here? Stop being a putz.
    You have been reported Kontact. Ad hominem name calling is against forum policy.

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