Shimano Alfine Crank

OrangePro
OrangePro Posts: 28
edited August 2010 in The workshop
Heading home tonight and the left hand crank arm slipped resulting in a very weird pedaling feel- took a while to work out what had happened. Arm has been a little loose recently and re-tightened. The probelm is - having re-tightened- have i done this too much as the threads now appear to worn?. Have stripped the crank, cleaned thoroughly, re-greassed but still slips when pressure applied.

No i didn't use a torq wrench and yes will buy one very soon.

Is there a way to ''re-thread' the crank arm or is it totally goosed with a new crank arm or even crankset needed? Have tried to locate replacement alfine crank arm but to no avail as yet.

Any suggestions ( apart from buying a torq wrench) would be greatly appreciated.

OP

Comments

  • nicklouse
    nicklouse Posts: 50,675
    there are no threads on the cranks arm, other than for the pedal and the crank puller threads.

    the fitting bolt has threads as doe the BB axle.

    if the bolt has stripped, get a new one and hope the BB is fine.

    if the crank has been ridden on lose have it inspected as you may have killed it and it will never stay tight.

    also you should not grease the tapers.

    Torque wrench not really needed.

    long spanner or long allen key and three grunts tight tends to do.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    Agree with Nick, FT is the only torque setting for tapered cranks.

    If (as I assume) its square taper, then you have a massive choice of arms, nothing special about one used with an Alfine.

    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.
  • OrangePro
    OrangePro Posts: 28
    Thank guys,

    Thought i'd got it sorted last night but on ride in this morning crank arm slipped. The BB is goosed so no hope- managed to get a replacement 20% off.

    Lesson learnt.
  • nicklouse
    nicklouse Posts: 50,675
    the BB could be fine but i bet the crank arm is dead.

    get it looked at.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    The hardened steel of the BB is probably fine, while as Nick says the soft alloy crank arm is probably what is dead.

    Pictures of arm, BB and bokt if you really are unsure of what is the issue.

    Having said that a friend of my daughters had this, replaced the arm and 2 weeks later the BB axle snapped.

    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.
  • OrangePro
    OrangePro Posts: 28
    Detailed inspection confirms all is not well. Crank arm without question is totally gone. The BB has some life left in it but has been severly compromised and as such may in the long-term potentially lead to a repeat problem of loosening crank arm. I want my communte bike to be dependable- i ride ss, stripped the dics to replace with v's and kool stops to get it as maintenance free as possible. Dont like riding my bike when you know its not what it should be- very unsettling especially in traffic.

    The upside is i've read tech sheet and now know what i'm looking at and doing ( i think)

    OP

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