Clunking sound

Discussion in 'Road Cycling' started by DougOnTwoWheels, Apr 19, 2020.

  1. DougOnTwoWheels

    DougOnTwoWheels New Member

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    I feel a little silly asking this, a bike isn't that complicated a machine, and I've been riding bikes for like 30 years, but I can't quite figure out what's going on here. I ride an older, but well-maintained aluminum frame Trek Roadbike, got it new shifters last summer actually.

    Anyway, I often hear like this rattling or clunking sound, like something hitting the spokes or frame. Almost as if I have a stick stuck in the frame or something. I noticed this a little last summer and initially thought it only happened when I peddled, but it happens sometimes when I'm coasting as well. It does seem to happen more when I'm peddling hard, and or, at higher gear ratios, and or going fast.

    I've flipped it over and spun the crank a few times but cannot duplicate it. I've looked for debris in the spokes, crank, or anywhere else but have not been able to locate it. I believe I experienced the clunking sound both before and after the new shifters were installed as well. Anyone know what's going on here? Should I be concerned?

    Thanks
     
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  2. cyclintom

    cyclintom Well-Known Member

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    It is time to look closely at the wheels. Cracking will start usually between two spokes but it can also start at the brake track if the wheels are old and the brake track is heavily worn. From your description I would think it more likely to be cracks between spoke nipples on the rim.
     
  3. DougOnTwoWheels

    DougOnTwoWheels New Member

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    You're saying the rim may be cracked?
     
  4. Mr. Beanz

    Mr. Beanz Well-Known Member

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    Sometimes the clunking comes from the floating of the cassette gears in the back. if you hold up the rear wheel and spin the pedals to get the wheel going fast, let it coast then you will see the gear set look as if it is floating. I have read on forums that this has made a clunking noise. Though it is pretty normal though some more than others.

    But if it is too loose, it will make different noises in different ways.

    I once built a rear wheel, installed it and it clicked like crazy. I thought it was the wheel I had just built so I stripped it down and started over. Same noise. Click while my left pedal was at 11 o clock. Then I started to think it was my crank. Re lubed, cleaned blah blah blah!

    Noise still there. Ended up taking the rear wheel off to clean then realized the lock ring on my rear gear set had somehow worked loose. Got the little tool and a wrench tightening it. NOISE WAS GONE!

    So it could be your rear cassette lockring is loose. Letting the cassette float around a little too much causing the knocking noise. Cheap fix, about $5 when I bought the socket looking tool. Make sure you get the correct tool if you get one.

    Or it could be the prawls inside the hub. I think they have been known to cause knocking type noises if I remember correctly.
     
  5. cyclintom

    cyclintom Well-Known Member

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    I have seen this make a clunking sound like this. But Mr. Beanz also has a good point. I also had a noise I couldn't trace and it turned out to be the cassette lockring was loose. Though this causes phantom shifting. Another similar source - the BB cup under the drive side cranks. Usually they can't back out enough to allow the crank to move much but I looked down and saw it.
     
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  6. Yojimbo_

    Yojimbo_ Well-Known Member

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    Check for loose or broken spokes.
     
  7. Froze

    Froze Well-Known Member

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    While it could be lots of things but I think, like everyone else is telling you, that you need to either inspect the wheels yourself, if you know how, if not take them to a bike shop and have them inspect them and check the spoke tension.
     
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