1992 Stumjumper M2 Bottom Bracket

unofficial

Dirt Disciple
Hey all I have an old Specialized M2 purple haze from 92 (I think) and I have noticed some play in the cranks. I took of the chain to confirm it wasn't the freewheel and indeed something in amiss in the bottom bracket.

The more I learn about repairing bikes the more I realise I know very little, seems like an uphill battle... :roll:

Anyway I don't have the tools necessary to remove the BB just yet but because there are 1000 factors in deciding if a BB will fit or not I wanted to check if anyone knew what BB replacement I need offhand.

The cranks are specialized and the BB shell seems to be wider than 73 but maybe I am not getting a good angle with my ruler... :oops:

Anyway anybody that could enlighten me would be much appreciated! :mrgreen:
 
From what I have found It looks like most specialized bikes of the era used 68mm English. Your best bet is to buy a BB tool and some grease that you are going to need anyway and take out the old one. Usually the size is marked on the BB and you can order a replacement.
 
Re:

73mm shell and if original cranks would hazard a guess at 122mm. Remove the cranks and measure the spindle length to confirm. Defo a 73mm shell on specialized of that era.
 
Re:

Hopefully these pictures work, the thing is I am so lost, it seems like I need a whole lot of tools, and that I need tools to open things just to see what other tools I need... I have no idea what to expect when I take this off or what I event need...

It seems like I will need a wrench to take the bolts off the pedals, a crank remover to get the cranks off, something to get that lockring off (not sure what is under the lockring and if that will need a tool too), a fixed cup remover.

I am curious what is living inside of there, when I do get those things off will I need more tools, are ball bearings going to come flying out?

I really wish there was a competent LBS around here when it comes to older bikes but there doesnt seem to be... If anyone has experience in this regard it would help a lot, otherwise I will have a go at it and see what happens!


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You need:

a crank extractor for a taper type crank. This removes the main crank bolt and then has a threaded section that screws into the crank threads, be careful and ensure it's in straight and fully home, the inner section then screws in and pulls/pushes the crank arm off.

a large adjustable spanner on the flats of the driveside bottom bracket cup will work, remember its threaded counter clockwise so turning it the opposite way from normal undoes it.

On the non driveside you'll need a good quality peg spanner for the cup. This undoes the normal direction.
For the outer lock ring you can get a lock ring tool which is like half a C with a tooth, or drifting in again the normal direction to undo, with a drift and hammer carefully should work.

No need to remove pedals and rings although it's always a good idea to make sure stuff isn't seized and threads are greased.

Hope this helps.
 
Re:

Yes thanks, that does help. I feel like at least I know what tools I will need to take things apart and then it will be another matter of replacing/ fixing the BB or whatever the source of play is,

Cheers!

ps I will have to order some tools but I will try to put up some pics when I open it up for future reference for anyone else.
 
konacarl":3m2k5lbr said:
Your need one of these to remove the arms:
http://www.chainreactioncycles.com/x-to ... -prod10181

and one of these (along with a spanner or ratchet/long pole (if its stuck) to get the BB out:
http://www.chainreactioncycles.com/park ... -prod17704

Have a look on ebay they're cheap enough.


As Kona Carl says, you definitely need the top type of tool but you have an older style bottom bracket, it doesn't use the second tool, which you will need if you replace what you have with a Shimano cartridge type BB.
 
Minifreak":30abwd5d said:
konacarl":30abwd5d said:
Your need one of these to remove the arms:
http://www.chainreactioncycles.com/x-to ... -prod10181

and one of these (along with a spanner or ratchet/long pole (if its stuck) to get the BB out:
http://www.chainreactioncycles.com/park ... -prod17704

Have a look on ebay they're cheap enough.


As Kona Carl says, you definitely need the top type of tool but you have an older style bottom bracket, it doesn't use the second tool, which you will need if you replace what you have with a Shimano cartridge type BB.

Well spotted! :oops:
 
Cheers! Speaking of replacing, I really wanted to keep the cranks and everything, any ideas of the top of the head what I should be looking for in a new BB that will still be compatible with my drivetrain?
 
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