Hammering in new crank arms

Discussion in 'Cycling Equipment' started by Risto Varanka, May 24, 2003.

Thread Status:
Not open for further replies.
  1. I am replacing my Nexave crankset with an Alivio one. I managed to remove the old cranks, but now I
    have trouble with the new ones which don't seem to want to go in. I applied some copper paste on the
    axle and smoothened it to as thin a layer as I could. Should I apply something more slippery
    instead? I tried heating the crank arms with a hair dryer and hammering them in using a solid hammer
    and a block of wood as a cushion... no apparent progress, even with pretty heavy hammering...

    How do you do it?

    --
    Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html varis at no spam please iki fi
     
    Tags:


  2. Richard Ney

    Richard Ney Guest

    [email protected] writes:

    > I am replacing my Nexave crankset with an Alivio one. I managed to remove the old cranks, but now
    > I have trouble with the new ones which don't seem to want to go in. I applied some copper paste on
    > the axle and smoothened it to as thin a layer as I could. Should I apply something more slippery
    > instead? I tried heating the crank arms with a hair dryer and hammering them in using a solid
    > hammer and a block of wood as a cushion... no apparent progress, even with pretty heavy
    > hammering...
    >
    > How do you do it?

    I would try a 4 lb--or even 20 lb--sledge hammer.
     
  3. Russell Yim

    Russell Yim Guest

    >I am replacing my Nexave crankset with an Alivio one. I managed to remove the old cranks, but now I
    >have trouble with the new ones which don't seem to want to go in.

    It's likely that the new Alivio crank has a different chainline requirement than the Nexave crank,
    so you need to change the sealed cartridge bottom bracket to a shorter axle in order to correct the
    chainline. I believe you can check Shimano's website to determine which cartridge you will need.
     
  4. Russell Yim

    Russell Yim Guest

    >I am replacing my Nexave crankset with an Alivio one. I managed to remove the old cranks, but now I
    >have trouble with the new ones which don't seem to want to go in.

    It's likely that the new Alivio crank has a different chainline requirement than the Nexave crank,
    so you need to change the sealed cartridge bottom bracket to a shorter axle in order to correct the
    chainline. I believe you can check Shimano's website to determine which cartridge you will need.
     
  5. Russell Yim <[email protected]> wrote:

    : It's likely that the new Alivio crank has a different chainline requirement than the Nexave
    : crank, so you need to change the sealed cartridge bottom bracket to a shorter axle in order to
    : correct the chainline. I believe you can check Shimano's website to determine which cartridge you
    : will need.

    According to Sheldon, Alivio MC16 is 110-113 while Nexave (T400 something maybe) is 117.5 mm spindle
    lenght. So... unless I change, my chainline will be screwed and not even my front derailleur will
    work? Didn't occur to my LBS, though, I specced the Alivio... :-(

    --
    Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html varis at no spam please iki fi
     
  6. Frank121

    Frank121 Guest

    Threading isn't a problem for very long...

    > : I would try a 4 lb--or even 20 lb--sledge hammer.
    >

    > And that does nothing to the threading of the bottom bracket? :-/
     
  7. S. Anderson

    S. Anderson Guest

    <[email protected]> wrote in message
    news:[email protected]...
    > I am replacing my Nexave crankset with an Alivio one. I managed to remove the old cranks, but now
    > I have trouble with the new ones which don't seem to want to go in. I applied some copper paste on
    > the axle and smoothened it to as thin a layer as I could. Should I apply something more slippery
    > instead? I tried heating the crank arms with a hair dryer and hammering them in using a solid
    > hammer and a block of wood as a cushion... no apparent progress, even with pretty heavy
    > hammering...
    >
    > How do you do it?
    >
    > --
    > Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html varis at no spam please iki fi

    I'm not sure why you're hammering so much. Something is not quite right. The heating with a hair
    dryer and greasing of the spindle are fruitless, the pressure from tightening the crank bolt makes
    all that grease disappear immediately. They're not going to affect the engagement of the crank that
    much. Step back and consider why you're hammering. If it's chainline problems, measure the BB axle.
    If the cranks simply aren't going onto the taper far enough, perhaps the taper angle is different. A
    hammer has its place, but I'm not sure this is it. You can hammer once or twice with a block of wood
    to seat the crank and tighten the crank bolt to it's correct torque, but to lay on the sledgehammer
    is not right.

    Cheers,

    Scott..
     
  8. Tbgibb

    Tbgibb Guest

    In article <[email protected]>,
    [email protected] writes:

    >I am replacing my Nexave crankset with an Alivio one. I managed to remove the old cranks, but now I
    >have trouble with the new ones which don't seem to want to go in. I applied some copper paste on
    >the axle and smoothened it to as thin a layer as I could. Should I apply something more slippery
    >instead? I tried heating the crank arms with a hair dryer and hammering them in using a solid
    >hammer and a block of wood as a cushion... no apparent progress, even with pretty heavy
    >hammering...

    You cannot get the new cranks to seat on the old spindle? Do I read that correctly? If so I wonder
    if you aren't trying to put a splined crank set onto a tapered BB axle (or the other way around).

    Tom Gibb <[email protected]
     
  9. TBGibb <[email protected]> wrote:

    : You cannot get the new cranks to seat on the old spindle? Do I read that correctly? If so I wonder
    : if you aren't trying to put a splined crank set onto a tapered BB axle (or the other way around).

    According to http://www.sheldonbrown.com/bbsize.html both should be square taper. Other than that,
    the symptoms sound just like that... Maybe I should make a few photos? :-.

    Splined BB shells seem to be only used on high-end stuff by Shimano. The BB spindle looks quite
    square, with tapered edges so it's sort of an octagon shape...

    --
    Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html varis at no spam please iki fi
     
  10. Andy Dingley

    Andy Dingley Guest

    On 24 May 2003 18:24:37 GMT, [email protected] wrote:

    >I am replacing my Nexave crankset with an Alivio one. I managed to remove the old cranks, but now I
    >have trouble with the new ones which don't seem to want to go in.

    How much do they go on ? Do they fit on the square at all ? Do they fit completely, but the
    chainline is wrong ? It's normal for some of the taper to be visible behind the crank, so long as
    they're on far enough for the bolts to go in. If they go on far enough for the axle to protrude
    through the crank socket, then you'd never be able to tighten them !
     
  11. Lol... I think I'm getting the picture...

    TBGibb <[email protected]> wrote:

    : I just measured the widest part of the taper inside a Shimano SGX crank. I got (with a moderately
    : good measuring device) 13.6 mm. I also measured a Shimano spindle on the outer end (I measured at
    : the point of initial contact between both parts) and it measured 13.0 mm. They oughta go togther
    : without a hammer, mine always have.

    Of course, the cranks slide in several millimeters! There is just this recess inside the crank... I
    mean, the axle doesn't come all the way up on the hole, and there's some millimeters space between
    the crank and the bike frame (amount depends heavily on which side is it). The old cranks actually
    seem to behave similarly... So this is actually normal? :D The crank tightening bolts need some
    space, and it's them that keeps the crank in place all the time?

    By the way, I measured my old bottom bracket spindle, and it seems to be 111mm, instead of the 117mm
    that Sheldon lists for different kinds of Nexave. That's weird, what gives? Could Nishiki have some
    kind of weird measurements on their hybrids, does some Nexave stuff use a narrower bottom bracket,
    or is it just not so critical after all? :-/

    Anyways, I'll just try putting it together now...

    --
    Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html varis at no spam please iki fi
     
  12. TBGibb <[email protected]> wrote:
    : In article <[email protected]>,
    : [email protected] writes:

    :>Of course, the cranks slide in several millimeters! There is just this recess inside the crank...
    :>I mean, the axle doesn't come all the way up on the hole, and there's some millimeters space
    :>between the crank and the bike frame (amount depends heavily on which side is it). The old cranks
    :>actually seem to behave similarly... So this is actually normal? :D The crank tightening bolts
    :>need some space, and it's them that keeps the crank in place all the time?

    : I'm going to have a real name for asking dumb questions here, but here goes:

    : How tight are you making the crank bolt?

    I'm not a real crank expert, but I tightened them as tight as I could. I mean, I could tighten them
    even more, but the tool slipped once and now the bolt doesn't look quite right any more. I'll just
    tighten them more after 100 km ;)

    Cranks seemed all ok now, 35 km of riding. Though I was underpacing myself... gotta train harder
    in June =)

    --
    Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html varis at no spam please iki fi
     
  13. Chris B .

    Chris B . Guest

    On 26 May 2003 01:34:46 GMT, [email protected] wrote:

    >I'm not a real crank expert, but I tightened them as tight as I could. I mean, I could tighten them
    >even more, but the tool slipped once and now the bolt doesn't look quite right any more. I'll just
    >tighten them more after 100 km ;)

    Really, you don't want to be chasing the cranks up the taper. If they were installed with adequate
    torque (around 30 lbs-ft) then they be fine. Unfortunately, from what I have seen, inexperienced
    people tend to undertighten crank bolts, especially with the allen head bolts that seem to be
    common now.

    Read the FAQ:

    http://www.faqs.org/faqs/bicycles-faq/part4/section-6.html

    Chris Bird
     
Loading...
Thread Status:
Not open for further replies.
Loading...