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  1. #1
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    XT front disc brake + 180mm alligator wavy rotor ->Weird noise

    It's a mystery to me. I built up a new bike over the weekend and took it out for a ride last night. Everything seemed fine and the brakes were broken-in by today. This afternoon, I went for a ride again. On a long downhill trail, I noticed that everytime I put on the front brake (whether just feathering or applying substantial force), this weird sound is produced. The tempo changes with how fast I'm riding and sounds like one of those twist drums from karate kid but much more muted and higher pitched. Sort of like a popping wiffle sound. The sound/noise was not present earlier during the ride and started mid ride. Everything seems ok on closer inspection, nothing is loose and the brake feels fine. No clearance issues at the calipers. The noise is present all the time now and does not matter what position the bike is in relative to the ground (perpendicular, leaned, pitched downhill). And yes, it is a different and separate sound from the normal sound produced when the pads are gripping the rotor and I can hear both sounds and they are separate/distinct from each other. It would be hard to reproduce it as the bike has to be moving at a substantial speed so I can't post a video. If it was happening in the rear then I could put the bike on a workstand but the rear brake is fine. Anyone have a similar experience with other caliper-rotor combos?

    Thanks!
    Hey man, wanna go for a klunk?

  2. #2
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    nuthin' eh?
    Hey man, wanna go for a klunk?

  3. #3
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    Reputation: oldskoolbiker's Avatar
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    I used to have Alligator rotors (the serration) and XT calipers. Those rotors don't dissipate heat very well and they were making my pads VERY hot. What ended up happening was that the pads would crack right down the middle and it was causing pulsating sounds every time I hit the brakes.

    I switched to the Shimano rotors and all problems went away. Those alligator rotors are light, but I wouldn't recommend them for anything other than XC or riding where you're not heavily braking (like dirt jumping).

  4. #4
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    Interesting. I gotta pull those pads out and check them then. Although, I doubt that I had already ruined them with 1 ride with only about 1000 feet of non-sustained elevation loss/downhill.
    Hey man, wanna go for a klunk?

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