Time to replace the BB on my Whippet (bought SH last year). However I can’t work out how to remove the left crank arm to start the process- the extraction ring thing which should sit in around the large bolt isn’t there. Any ideas of a way round this??

While I’m here, removing the BB and replacing seems fairly simple with the right tool, is it really just a case of knock it out and knock the new one in?

M970 xtr?

You got the extractor tool?

If not, go get one. If you have, what you say doesn’t make sense, got pics?

If it’s newer XTR I can’t help, sorry.

I don’t have the extractor tool, I wasn’t sure if I needed it so thought I would look/ ask first. Not sure on which model the cranks are I’m afraid!

This is what I have….

Untitled by northdownsouth2012, on Flickr

Untitled by northdownsouth2012, on Flickr

They’re M970s – google will sort you out the instructions I’m sure. They’re different to other hollow tech cranks so you really should read them before you break or strip something.

There’s a dedicated tool for the tension collar behind the left arm. You can get away with out that.

There’s a dedicated puller tool that threads in the arm, you then use the bolt like a self extractor. You need this tool.

http://www.chainreactioncycles.com/shimano-xtr-left-hand-crank-removal-tool-m970/rp-prod25630

Is it, but you can probably pick one up cheaper somewhere or borrow one. It’d be nearly impossible to bodge it and you run the risk of damage.

I do of course eagerly await someone’s tales of how you don’t need the tool and they just pulled the arm off with their teeth…

Yep, those are M970. You need the tool which reverse-threads into the end of the crank. Keep the crank bolt in place, screw in the tool, then undo the crank bolt – everything comes off together.

Wait, how did you get the bolt out? There should be a collar thingy threaded in around it (you use the prongs on that extractor to remove it before you flip it over and thread it in).

I just took he bolt out with an 8mm Allen key- thought I might need the tool- will hunt one down.

Is he missing collar important?

Not really – I think it just keeps the threads clean. I lost mine around 2 years ago and no real issues – I’ve taken the cranks on & off at least 7-8 times. Just make sure the threads are clean before you thread the tool in – they’re pretty fine alloy threads so the potential for damaging them is significant.