hollow knocking noise?

bobs bikes
bobs bikes Posts: 589
edited May 2010 in MTB workshop & tech
right, im a bit stumped! :shock:

my hardtail has developed a wierd noise which i just cant pinpoint.
it is a loud hollw sounding clunk on every pedal stroke when pushing hard which you can feel through the pedals, but no noise or feel when normal riding.the frame is aluminium, forks are fine. they are marzocchi dirtjam pro. so far i have done....
bottom bracket, replaced the sealed unit.
pedals
rear wheel bearings and cups
headset bearings
chain and groupset.
.......
its really peeing me off!

sod's law, i can sort any customers bike out, but mine.... feck knows!

Comments

  • nicklouse
    nicklouse Posts: 50,673
    well i would say you know the Parktools check-list well. so lets throw some things about.


    what gear is it happening in?

    and you have checked for cracks.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • bobs bikes
    bobs bikes Posts: 589
    hi mate, its happening in all gears! its litterally as soon as i put any force on the pedals, so obvious thought is bottom bracket or broken rear axle, both checked and changed. the noise is a deep clunk so has to be reverbing through the frame somewhere, the pedals were trivial, but changed them anyway. everything is tight and set up fine. the front end is fine, so no shock issues. just a bit odd. frame is also fine. the bike is smooth as you like while riding normally. it happens on or off the saddle..
  • nicklouse
    nicklouse Posts: 50,673
    only things that come to mind is lose chain ring bolts, or worn teeth causing the chain to move.

    a hard one to guess.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • spidan
    spidan Posts: 59
    Have you checked the cassette? tighten
    Giant XTC3.5 Maxis tyres, Shimano deore cranks, superstar bits and bobs
  • Thread8
    Thread8 Posts: 479
    Brake pads rocking in the caliper due to rotor rub?
    Haro Thread 8
    Please help!

    "It's like parkour, on a bike"
  • bobs bikes
    bobs bikes Posts: 589
    i have recently changed the chain and rear cassette, so thats a no. the brake pads were changed this morning, so thats a no...
    the noise is a loud clunk.

    its probably my knees! :lol:
  • The Rookie
    The Rookie Posts: 27,816
    I had that and it turned out to be a 'stiff' link in the chain, bit of lube fixed it.....I know you have a new chain, but wirth checking every link?

    SImon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

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