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Got any ideas on how to free a stuck crankarm?

FoldingJoeFoldingJoe Posts: 1,327
edited May 2012 in The workshop
Guys,

I took my crankarm off my powertorque chainset a few weeks back, gave it a re-grease, and replaced it.

Just tried to take it off again today and it is stuck solid..no budging it with the crank puller.

Can anybody think of any ways to get the thing off?

I tried riding it for a while at lunchtime without the nut on, but even after 12 miles it is still stuck fast.

Would heating the crankarm directly give it a chance?

I'm starting to think I should switch to SRAM of Shimano!! :(

Cheers,
FJ
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Posts

  • asprillaasprilla Posts: 8,440
    I took an ultegra one off at the weekend by hitting it with a rubber mallet. Repeatedly.
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  • tgotbtgotb Posts: 4,714
    I've solved this problem in the past by heating; that's always been an aluminium crank on a steel spindle, and aluminium has a higher coefficient of expansion than steel (accentuated by the fact that you should be heating the crank more than the spindle).

    Don't know whether Powertorque has a steel spindle, but even if it's aluminium it's still worth a try...
    Pannier, 120rpm.
  • Drfabulous0Drfabulous0 Posts: 1,539
    Crank puller with a bigger lever usually does the trick, i have an old seatpost just for this.
  • rjsterryrjsterry Posts: 22,306
    Don't know about Powertorque, but I presume it's still a splined connection of sorts. I doubt it would be an aluminium spindle. TBH, if the crank puller isn't working - and you get a lot of leverage from them as a whole turn of the wrench will move the crank maybe 1mm (not sure on thread pitch 'n' stuff) - then thumping it isn't going to be any better. No harm in trying the heating idea, but be careful to not damage anything else in the process (obv).
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  • FoldingJoeFoldingJoe Posts: 1,327
    OK, sounds like heating is the way to go...

    How do you hold your bike over the gas ring on the cooker though? ;)
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  • tgotbtgotb Posts: 4,714
    FoldingJoe wrote:
    How do you hold your bike over the gas ring on the cooker though? ;)
    I waited until my other half was out :-)

    I used a heat gun, until the crank arm was too hot to touch (was probably still well under the 100 degrees the outside of my kettle gets to) and then wound on the crank puller. It popped off quite easily.

    If your crank has any sort of painted/lacquered cosmetic finish (mine didn't) you might want to try a gentler heat source, and compensate by heating for longer...
    Pannier, 120rpm.
  • Greg TGreg T Posts: 3,266
    The last time I had this problem I found that removing the crank bolt holding it onto the bottom bracket helped a lot

    I'm not kidding . . . was at it for hours
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  • FoldingJoeFoldingJoe Posts: 1,327
    Greg,

    You know what, the crank bolt had been removed, but upon further inspection I saw a washer in there.

    I thought that was my Eureka moment, and was sure it would come off after that...but alas, NO!! :D
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  • tgotbtgotb Posts: 4,714
    Greg T wrote:
    The last time I had this problem I found that removing the crank bolt holding it onto the bottom bracket helped a lot
    Ha ha! Yes, I've been there!

    If there's one thing that's harder than removing a stuck crank, it's removing a stuck crank with a stripped extractor thread...
    Pannier, 120rpm.
  • veronese68veronese68 Posts: 25,283 Lives Here
    We use some pretty big pullers at work for splitting car hubs that are on a taper. The puller works in much the same way as a crank puller. Tighten the puller as much as you can, then beat the censored out of the end of the crank with a mallet (plastic or hide would be best) if it doesn't pop tighten the puller a bit more and repeat.
    When the car hubs are done they take a lot of abuse and can eventually let go with an almighty bang.
  • centimanicentimani Posts: 467
    Just a thought...
    Having just got a Veloce clad bike with a powertorque crank, doing some homework, i read you use a plug in the hollow axle to locate the puller nose to.
    Is the plug being located properly ? If its catching the crank itself, it will of course stop the crank coming off.
  • mattcroadmattcroad Posts: 189
    TGOTB wrote:
    Greg T wrote:
    The last time I had this problem I found that removing the crank bolt holding it onto the bottom bracket helped a lot
    Ha ha! Yes, I've been there!

    If there's one thing that's harder than removing a stuck crank, it's removing a stuck crank with a stripped extractor thread...

    I've just removed one like this...



    ...with a hacksaw! The cranks metal is normally quite soft (light) so can be cut through in about a minute. However if you plan one re-using this isn't the best method :D
    There is a rule for that
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  • centimanicentimani Posts: 467
    Coming back to this one a bit late, but here's what i found...
    Granted, i was using small pullers, proper ones though, the crank didnt come off that easily, it took a bit of force to get it going...quite a bit.
  • FoldingJoeFoldingJoe Posts: 1,327
    Centimani, when you say proper ones, do you mean the park tool ones, or some you bought elsewhere?
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  • centimanicentimani Posts: 467
    FoldingJoe wrote:
    Centimani, when you say proper ones, do you mean the park tool ones, or some you bought elsewhere?
    No not Park ones...ive devised a homebrew setup, i'm going to take some photos and post a ...errr post :oops:
    Pullers are only small, something i got off a carboot a couple years ago for 50p, they only open a couple inches, small legs and about a 10mm driving screw.
    Made an aluminium plate to go round the back of the crank to protect it..and used a 3/8 drive socket, just smaller than the OD of the axle. It all worked fine.

    I am going to do a post in a few days...
  • FoldingJoeFoldingJoe Posts: 1,327
    Well, had a bash at it today, and did an "Italian Job" on it.

    As Veronese suggested, tightened the puller to the max, and gave it some *taps* ;) with a rubber mallet, which after a few more tightens on the puller it started to work it's way off.

    Thanks for all the input. Might try some PTFE tape on there next time to see if that helps free it in the future.

    Thanks again,
    FJ
    Little boy to Obama: "My Dad says that you read all our emails"
    Obama to little boy: "He's not your real Dad"

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  • godders1godders1 Posts: 750
    TGOTB wrote:
    Greg T wrote:
    The last time I had this problem I found that removing the crank bolt holding it onto the bottom bracket helped a lot
    Ha ha! Yes, I've been there!

    If there's one thing that's harder than removing a stuck crank, it's removing a stuck crank with a stripped extractor thread...
    I can testify to that. After several attempts using more subtle techniques I resorted to the angle grinder (good job it was a cheap chainset and BB!).
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