Crank removal?

[a-n-wilson]

Hi, I've got a Specislised roubaix pro 2018 with s works cranks on an OSBB. I think that a bearing has loosened, which has pushed out a collar.
I reckon that all I need to do to fix it is take the cranks off then push it back into place,but the problem is that I can't take the cranks off!
I can undo the one Allen key bolt up to a point, but then it tightens again. There's a collar over the top of it with two small indentations, I'm wondering if this needs to have something done to it.
So, does anyone have any ideas what I can do to get past the point that the bolt starts to retighten and do get the cranks off? If you can help, it would be much appreciated as I'm going stir crazy being stuck in! Many thanks.

 

[a-n-wilson]

Here are a few photos of it. Thanks all.

 

[raleighnut]

That looks like a 'self extracting' crank to me, the same bolt that holds it onto the taper pushes against the inside of that collar to remove the NDS crankarm, I could be wrong but I've seen similar on Truvativ cranksets.

 

[a-n-wilson]

Thanks for your reply. Would you know how to take it off?

 

[figbat]

That looks like a 'self extracting' crank to me, the same bolt that holds it onto the taper pushes against the inside of that collar to remove the NDS crankarm, I could be wrong but I've seen similar on Truvativ cranksets.

That would be my conclusion too. A self-extracting bolt does tighten again as you unwind it because it is pushing against the crank arm to loosen it from the axle. The bolt remains captive in the crank arm.

 

[ColinJ]

Yes, self-extracting.

I have that arrangement on the chainset that I posted a picture of elsewhere today. This one...

PS I have just noticed that one of my self-extractor caps has fallen off. Make sure that you keep yours done up tight enough!

 

[raleighnut]

That would be my conclusion too. A self-extracting bolt does tighten again as you unwind it because it is pushing against the crank arm to loosen it from the axle. The bolt remains captive in the crank arm.

Ah but as you undo the bolt it will seem to 'tighten' up as it presses against the cap ring until that force overcomes the fit onto the tapered splines.

 

[a-n-wilson]

Hi all, thanks for the responses,but what do I literally have to do to take it off?

 

[a-n-wilson]

To be fair, I think I've got it. So, I've ordered a pin spanner to take the captive bolt off, then I should be able to just keep turning the Allen key I reckon to take the cranks off. At that point i push the bearing back in, tighten the collar, whack the cranks on and BOSCH! I'm hammering down the country lanes of North Yorkshire! Anybody see any serious flaws in that plan? Thanks all!

 

[si_c]

You remove it with a hex key.

Video here should demonstrate the principle.

 

[byegad]

Hi all, thanks for the responses,but what do I literally have to do to take it off?

Keep turning after it tightens back up, it will pull the Crank off with it, hence self extracting.

 

[a-n-wilson]

Many thanks!

 

[figbat]

To be fair, I think I've got it. So, I've ordered a pin spanner to take the captive bolt off, then I should be able to just keep turning the Allen key I reckon to take the cranks off. At that point i push the bearing back in, tighten the collar, whack the cranks on and BOSCH! I'm hammering down the country lanes of North Yorkshire! Anybody see any serious flaws in that plan? Thanks all!

No need for a pin spanner - that collar has to stay in place. All you need is the correct hex socket or allen key to undo the crank.

 

[a-n-wilson]

I've definitely got the right allen key, but once it loosens it just retighten on the captive boltto the point where it won't go further. Should I just push on through? Cheers.

 

[carlosfandangus]

I have the same set up on a MTB, (octalink) just unwind, the tightening you mention is just the allen bolt putting pressure on the crank arm to push it off the crank spindle, I have an FSA crank off another bike on the shelf in the garage, that is the same, do not undo the ring (pin holes) the crank will not push off if this is removed