MAVIC 631 crank help

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?

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

"Baird Webel" wrote in message
...
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.

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

I believe I may have one in my spare stuff stash at the shop. I'll look
and get back to you tomorrow.
Jim

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

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.

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

"Johnny Parks" 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

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