M950 XTR advice
- Thread starter AWK
- Start date
Barberossa79
Retro Newbie
Interesting, hadn't thought of it that way round. Was thinking the other way round that the 950 would cover the wider chainring distance slightly better.
pwebb
Senior Retro Guru
biggest issue is top pull versus bottom pull front mech surely? - as no option to mix/match when it comes to braze-ons and cable routing. I would also express some caution on chainring compatibility - be careful what you buy on ebay etc as some of the newer XTR chainrings have a peculiar off center inner 4 bolt pattern that isnt interchangeable with earlier XTR but looks the same from a distance ( sorry I dont have the technical dimensions stored in my head like the gurus here) I would say that provided you get the correct fitting ( octalink) the BBs from lower down the shimano range also work aok - if that means you can secure the correct width for your chainline more easily/cheaply though pukka XTR BB weighs a lot less. great info in this thread already though for XTR hoarders ;-0 Finally, for the very brave, I did find a shade of Halford's rattle can car paint that exactly matches the darker grey and managed to restore a very scuffed non driveside crank - plus decals can be sourced on ebay too.
Barberossa79
Retro Newbie
Not sure about top v bottom pull so if anyone can advie that would be appreciated.
I managed to get hold a genuine 950 bb after i got the chainset. It's been a bit of a journey of ignorance for me, hadn't realised there even was a V1 Octalink as my first one if note was a slightly later LX V2. And to be honest when I got the bag of XTR swag I didn't full appreciate the differences between what I ended up with.
A 96 Zaskar is a 31.8 BP.
pwebb
Senior Retro Guru
Yes, sorry should have been more explicit that bottom pull has gear cable routed underneath the BB and so the cable joins the front mech from below. Top pull routes the gear cable along the top tube down the seat tube and joins the front mech from above.
Newer mechs can be both top and bottom pull and latest are often side pull now. It's easy enough to check your cable routing by the position of cable stops brazed onto the frame and on older frames the cable guides under the BB.
Newer mechs can be both top and bottom pull and latest are often side pull now. It's easy enough to check your cable routing by the position of cable stops brazed onto the frame and on older frames the cable guides under the BB.
Barberossa79
Retro Newbie
Understood yes its BP, will have to check the FD's and see what they are.
Ok, so some more info.
The 4 arm middle chain rings are a specific BCD iirc and so you can't bolt on any old 104bcd chain ring, or even the modern and confusing 110bcs 4 arm.
There was a DH outer ring, but that required it's own spider to work with the bcd of the ring which iirc was 112mm 5 arm.
There were 3 iterations of the brakes. Though 2 carried the same model number of m950. One variant had ti cut out linkage things, the other black and solid. I think the linkage mounting changes between these two.
A further linkage change for m951 which also had a tension spring on the linkage.
Other things I've come across.
M952 BB not fitting an m950 crank. I've had others that did so not sure why in that case.
The m950 front mech isn't that great. I'd use an m953 if it were me (and I do).
Cranks have 3 spiders by Shimano, the integrated outer ring version, the 5 arm 110bcd and the dh one.
Aftermarket options for 104bcd and 94 BCD were available from various brands once upon a time.
M950bb is rebuild able if you can find the spare bearing parts. I have seen someone convert one to use sealed bearings. You can if you are brave enough, take an m952 BB apart and service. Never tried.
Brake levers didn't change model number and were m950 throughout.
There is also a bar end shifter that allows you to shift the rear mech from the bar end. Works quite nicely actually.
Shimano flight deck was compatible with m950 and m952 shifters.
When fitting the BB to the cranks, it is best to remove the bolts and self extractors so you can slot it together otherwise you are blind. It only engages a little with the bolts in situ and you can damage the crank splines.
If I think of anything else I'll add.
The 4 arm middle chain rings are a specific BCD iirc and so you can't bolt on any old 104bcd chain ring, or even the modern and confusing 110bcs 4 arm.
There was a DH outer ring, but that required it's own spider to work with the bcd of the ring which iirc was 112mm 5 arm.
There were 3 iterations of the brakes. Though 2 carried the same model number of m950. One variant had ti cut out linkage things, the other black and solid. I think the linkage mounting changes between these two.
A further linkage change for m951 which also had a tension spring on the linkage.
Other things I've come across.
M952 BB not fitting an m950 crank. I've had others that did so not sure why in that case.
The m950 front mech isn't that great. I'd use an m953 if it were me (and I do).
Cranks have 3 spiders by Shimano, the integrated outer ring version, the 5 arm 110bcd and the dh one.
Aftermarket options for 104bcd and 94 BCD were available from various brands once upon a time.
M950bb is rebuild able if you can find the spare bearing parts. I have seen someone convert one to use sealed bearings. You can if you are brave enough, take an m952 BB apart and service. Never tried.
Brake levers didn't change model number and were m950 throughout.
There is also a bar end shifter that allows you to shift the rear mech from the bar end. Works quite nicely actually.
Shimano flight deck was compatible with m950 and m952 shifters.
When fitting the BB to the cranks, it is best to remove the bolts and self extractors so you can slot it together otherwise you are blind. It only engages a little with the bolts in situ and you can damage the crank splines.
If I think of anything else I'll add.
bikeworkshop
Old School Grand Master
Iirc Xtr octalink isn't the same as the cheaper mtb units.
If you mismatch the splines you'll ruin the chainset. It's been done many times, making an xtr m950 chainset a risky buy.
Symptoms? Creaking and falling off, like square taper
Iirc Xtr octalink isn't the same as the cheaper mtb units.
If you mismatch the splines you'll ruin the chainset. It's been done many times, making an xtr m950 chainset a risky buy.
Symptoms? Creaking and falling off, like square taper
Only V1 105 is a substitute but it’s the wrong lengths.
If folk insist on using a XTR chainset then they can’t complain about £40-50 for a BB to fit it in my opinion.
All the others have different splines which damage the cranks splines
