MAVIC 631 crank help

Discussion in 'Cycling Equipment' started by Johnny Parks, Feb 6, 2006.

  1. Johnny Parks

    Johnny Parks Guest

    I have been running a Mavic 631 crank on my rain bike for a few years
    now. I love the crank and not just because it is retro.

    Anyways...

    Recently I noticed that I was missing the bolt which threads into the
    crank itself which allows the chainring bolt to be attached to the
    crank. I'm not speaking of the chainring bolt (those of you who have
    this crank or have worked on them extensively know what I am talking
    about).

    Any idea where I can find a replacement for such a thing? Does anyone
    know of a shop or distributor that hoarded parts for these cranks?
     
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  2. Baird Webel

    Baird Webel Guest

    Johnny Parks wrote:
    > I have been running a Mavic 631 crank on my rain bike for a few years
    > now. I love the crank and not just because it is retro.
    >
    > Anyways...
    >
    > Recently I noticed that I was missing the bolt which threads into the
    > crank itself which allows the chainring bolt to be attached to the
    > crank. I'm not speaking of the chainring bolt (those of you who have
    > this crank or have worked on them extensively know what I am talking
    > about).
    >
    > Any idea where I can find a replacement for such a thing? Does anyone
    > know of a shop or distributor that hoarded parts for these cranks?



    Ouch...not a good piece to lose. I don't know of a perfect replacement,
    though what could be done is get a longer chainring bolt that will go
    through both rings and the spacer and into the crank, it won't fit as
    nicely in the outer ring, but it should hold it all together well
    enough. I assume you'll need to get a spacer as it was probably lost as
    well, but any shop should have chainring spacers that will work.

    I'm curious...what bottom bracket are you running with it?

    Baird
     
  3. "Baird Webel" <[email protected]> wrote in message
    news:[email protected]
    > Johnny Parks wrote:
    >> I have been running a Mavic 631 crank on my rain bike for a few years
    >> now. I love the crank and not just because it is retro.
    >>
    >> Anyways...
    >>
    >> Recently I noticed that I was missing the bolt which threads into the
    >> crank itself which allows the chainring bolt to be attached to the
    >> crank. I'm not speaking of the chainring bolt (those of you who have
    >> this crank or have worked on them extensively know what I am talking
    >> about).
    >>
    >> Any idea where I can find a replacement for such a thing? Does anyone
    >> know of a shop or distributor that hoarded parts for these cranks?

    >
    >
    > Ouch...not a good piece to lose. I don't know of a perfect replacement,
    > though what could be done is get a longer chainring bolt that will go
    > through both rings and the spacer and into the crank, it won't fit as
    > nicely in the outer ring, but it should hold it all together well enough.
    > I assume you'll need to get a spacer as it was probably lost as well, but
    > any shop should have chainring spacers that will work.
    >
    > I'm curious...what bottom bracket are you running with it?
    >
    > Baird


    I suggest that the OP contact Mavic USA. They've helped me out in the past.
    The part # is 631-007. You can also try contacting XXcycles in France.
    They've found some Mavic stuff for me. Also Euroasia in USA may be able to
    help. Have your shop contact them.

    Re: BB- I await to hear what you use. I had Phil send me a 113, but now I
    forget if it was JIS or ISO taper. Search this ng for some discussions on
    the topic of non-Mavic BB's for 631 canks. Mavic 631 is ISO taper according
    to what I've read. Wish I could find the right ISO spindle for my Mavic VTT
    crank.

    Gary Jacobson
    Rosendale, NY
     
  4. I believe I may have one in my spare stuff stash at the shop. I'll look
    and get back to you tomorrow.
    Jim
     
  5. Sorry, J.P., I cannot find the part that I thought I had stashed for
    this crank. I also called Euro-Asia Imports, and they do not have
    spares either. May have to find a whole crank to strip for spare parts.
    Good luck.
    Jim
     
  6. Johnny Parks

    Johnny Parks Guest

    Meccanico di Bici wrote:
    > Sorry, J.P., I cannot find the part that I thought I had stashed for
    > this crank. I also called Euro-Asia Imports, and they do not have
    > spares either. May have to find a whole crank to strip for spare parts.
    > Good luck.
    > Jim


    Thanks for checking Jim.

    A friend/teammate actually has a crank stashed away that'll he'll give
    me.

    Some people asked about what BB I use. I have been runing an old
    school (circa 1989) Dura-ace BB. Not sure what the spindle length is.
    I know that technically the taper on that BB should not work with the
    crank, but it does. I've never had a problem with it. What's funny is
    the guy who is giving me the other crank ran the same set-up with no
    problem either. I had to re-tap the threads on the right crank arm
    when I got it. They were very nasty. That is the only problem I ever
    had with the crank....until now.
     
  7. I also used a 631 on a D-A spindle on an old Miyata TT bike. At the
    time I didn't know any better, but it workd just fine and did no damage
    to the crank that ultimately did go onto a Mavic bb on a diferent
    frame. Cheers.
    Jim
     
  8. "Johnny Parks" <[email protected]> wrote:

    > > Some people asked about what BB I use. I have been runing
    > > an old school (circa 1989) Dura-ace BB. Not sure what the
    > > spindle length is. I know that technically the taper on that BB
    > > should not work with the crank, but it does. I've never had a
    > > problem with it. What's funny is the guy who is giving me the
    > > other crank ran the same set-up with no problem either.


    "Meccanico di Bici" wrote:

    > I also used a 631 on a D-A spindle on an old Miyata TT bike.
    > At the time I didn't know any better, but it worked just fine and
    > did no damage to the crank that ultimately did go onto a Mavic
    > bb on a diferent frame. Cheers.


    I understand that the Dura Ace 7400 spindle used an ISO taper, right up
    until 1992.

    Just to add a little dimensional information to the pool, I recently bought
    a Mavic cartridge bottom bracket (on ebay.fr). The axle length is 116mm.
    The total width across the shell is 78mm. The right hand ("FIXE")side axle
    overhang is 20mm and the left ("MOBILE") side 18mm. There's what I take to
    be a date code on the "FIXE" cup: 9306C.

    Fitting a 631/2 left hand crank to the Mavic axle with hand pressure, the
    axle comes to within 4.7mm of the end of the taper. With a Shimano UN72,
    the distance is 7.4mm.

    James Thomson
     
  9. A Muzi

    A Muzi Guest

    Meccanico di Bici wrote:

    > I also used a 631 on a D-A spindle on an old Miyata TT bike. At the
    > time I didn't know any better, but it workd just fine and did no damage
    > to the crank that ultimately did go onto a Mavic bb on a diferent
    > frame. Cheers.


    "didn't know any better"??

    The Dura Ace #7400 series BB is a directly interchangeable
    copy of the Campagnolo 1046a Nuovo Record BB as is the Mavic
    610 series BB.

    Sometimes riders overlook that the revisionist "shimano
    type" spindles, so pervasive now, are of very recent birth.

    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
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