Mavic 631 bb compatibility

[Mike Muz]

Hi fellow retro roadies

I was, er, just wondering :roll: if Mavic 631 chainsets have dedicated bottom brackets, or whether they are compatible with either Shimano or Campag ones? If they are compatible, what length of axle do they need?
I tried Sheldon Browns database, but without success.
If they're Mavic specific, are they Engllish or Italian threaded?
All help gratefully received, but, um, for no specific reason, maybe :facepalm:

ta,


Mike

 

[onegoodbike]

Re:

Hi Mike, this is a timely question as far as I'm concerned too.
I have recently acquired a Mavic chainset and am currently running it on a Gipiemme B/B which has ISO tapers the same as Campagnolo B/B's. I've been lead to believe, by a bit of online research, that this is preferable to JIS tapers found on Shimano offerings?.
I've also read that the cranks should run on a 114mm axle (the size of the original Mavic 610 B/B) regardless of whether it is English or Italian thread, but I'd be happy to hear if anyone else can shed some more light on the subject as I'd like to get it right for my bike .

Matt

 

[mdvineng]

Re: mavic bb

The mavic chainsets all use ISO tapers and it is best to avoid any other type of taper fitting to prevent cracking. The double ring sets use 114mm axles and the triples use 119mm. Any ISO taper BB of114mm will do the job but my preference is for the original Mavic 610 BB's, as they allow for some adjustment to the chainline if needed and are very reliable and smooth. See Velobase.com for other details.

 

[Mike Muz]

Re:

Thanks for your help lads, been toying with the idea of something a bit different from the normal Shimano/Campag equipped bikes we build.
I shall start looking for a chainset now, in 175mm. Wish me luck

Mike

 

[stringfellow1946]

If you use a Mavic 610 series BB, the Bottom Bracket shell on the frame will need to be tapered, (by 45deg IIRC?) Mavic made a special tool for this job. Also the bearings used in the Mavic bottom brackets were a one off size made for especially for Mavic & they are no longer available & I've yet to find an industry standard replacement.

 

[94chas]

Re:

Hi had mavic 630 cranks and bottom bracket on mine removed the cranks and fitted campag chorus they fitted straight on no chain alignment required this was 20 years ago their still on and im still riding it

 

[mdvineng]

If you use a Mavic 610 series BB, the Bottom Bracket shell on the frame will need to be tapered, (by 45deg IIRC?) Mavic made a special tool for this job. Also the bearings used in the Mavic bottom brackets were a one off size made for especially for Mavic & they are no longer available & I've yet to find an industry standard replacement.

I haven't found an industry std one either but they are originally std but the outer diameter is reduced to the size mavic wanted. I plan to make some in the future from Std size sourced from Simply bearings Ltd and use a tool post grinder on my lathe to make them fit, I have plenty of good ones around so I'm not in a rush to do this this year. Any good machine shop could do this.

 

[stringfellow1946]

If you use a Mavic 610 series BB, the Bottom Bracket shell on the frame will need to be tapered, (by 45deg IIRC?) Mavic made a special tool for this job. Also the bearings used in the Mavic bottom brackets were a one off size made for especially for Mavic & they are no longer available & I've yet to find an industry standard replacement.

I haven't found an industry std one either but they are originally std but the outer diameter is reduced to the size mavic wanted. I plan to make some in the future from Std size sourced from Simply bearings Ltd and use a tool post grinder on my lathe to make them fit, I have plenty of good ones around so I'm not in a rush to do this this year. Any good machine shop could do this.

The ones that I found in the SB catalogue or on the Net somewhere & this is from memory so may not be absloutly 100% correct.
OK from what I remember The originals are 8 or 10mm thick with a 16mm bore & 30mm OD
The closest std bearings I could find were 30mm OD. 17mm Bore, 7mm thick, to be able to use these bearings would involve making 2 shims for each bearing (4 for the complete axel) one to sleeve out the bore & one to pad out the thickness of the bearing.
Without dismantling an axel to check I not 100& sure on the dimensions BUT the ones I have looked at all had MAVIC stamped on them so I assume they were a special order done for MAVIC??

 

[mdvineng]

Sorry for the late response but I've been away. The bearings I would use are 16mm inner diameter 31mm outer (needs grinding down to 30mm as did Mavic to theirs) 10mm width as the 9mm ones as std are no longer available. This extra width can be accomodated in two possible ways 1) remove 1mm from from each side of the axle where the bearings butt up to. 2) remove 1mm from the inner face of the bearing adjusters, though this would weaken them and is probably best avoided.