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Removing a sprocket

lost_in_thoughtlost_in_thought Posts: 10,563
edited May 2009 in The workshop
Hi there,

I know this has come up before in CP's thread, but that dealt more with cranks and less with sprockets.

I've obtained some second hand wheels, which have an 18t sprocket with lockring, and I want a 14t.

Now, I've used the 'hammer and screwdriver' method and managed to remove the locking, but can't get the bloomin' sprocket off.

A couple of questions:

The lockring unscrewed the 'wrong' way - ie not righty tighty lefty loosey :)

Will the sprocket unscrew the same way as the lockring or the opposite way?

How the heck do I get it off? I have a chain whip but am not entirely sure how to use it.

Also, I have a lockring-less 14t on the old wheels which I may or may not reuse - which way will that unscrew?

Any tips for loosening the darn things up also gratefully received.

Posts

  • redveeredvee Posts: 11,921
    The sprocket/freewheel should unscrew the opposite way to the pedal action, ie counter-clockwise. Pedalling tightens the srocket/freewheel onto the hub.
    I've added a signature to prove it is still possible.
  • crankycrankcrankycrank Posts: 1,830
    Here you go... http://en.wikipedia.org/wiki/Fixed-gear_bicycle Including picture of proper use of your chain whip which is shown mounted to turn the sprocket in a clockwise rotation.
  • lost_in_thoughtlost_in_thought Posts: 10,563
    Here you go... http://en.wikipedia.org/wiki/Fixed-gear_bicycle Including picture of proper use of your chain whip which is shown mounted to turn the sprocket in a clockwise rotation.

    Oooooh thanks!
  • crankycrankcrankycrank Posts: 1,830
    You're welcome, my pleasure!
  • lost_in_thoughtlost_in_thought Posts: 10,563
    OK, so tried the chainwhip technique last night, could not move the sprocket at all. Not even a little bit.

    Any tips for loosening it up?

    Is it possible to unscrew it by clamping the wheel and pedalling backwards (it's a FG) somehow?

    Also, there's a lot of conflicting information re the thread direction of a sprocket with lockring - the wiki site says it unscrews the same way as the lockring, ie clockwise, but the site it quotes as a source maintains that the sprocket unscrews anti-clockwise.

    I agree that unscrewing clockwise makes a lot more sense, but then what's the lockring for?

    Confused...
  • ride_wheneverride_whenever Posts: 13,279
    you could try sticking it in the bike, backing up to a wall and then stamping on the rear pedal to try and reverse, that might get it loose, a better idea would be to use a kettle of just under boiling water just in case it was threadlocked on.

    Or put a piece of scaffold pipe over the chain whip for more leverage. DO NOT use the hoover pipe, you'll just bend it (found that out the hard way!!!!)
  • redveeredvee Posts: 11,921
    You do need to secure both ends of the chainwhip, easy for it to jump as I found out when putting my fixed sprocket on last night with overkill of copper grease on lockring and sprocket. Can't see me using it though but it looks better than a bare thread.
    I've added a signature to prove it is still possible.
  • crankycrankcrankycrank Posts: 1,830
    OK, so tried the chainwhip technique last night, could not move the sprocket at all. Not even a little bit.

    Any tips for loosening it up?

    Is it possible to unscrew it by clamping the wheel and pedalling backwards (it's a FG) somehow?

    Also, there's a lot of conflicting information re the thread direction of a sprocket with lockring - the wiki site says it unscrews the same way as the lockring, ie clockwise, but the site it quotes as a source maintains that the sprocket unscrews anti-clockwise.

    I agree that unscrewing clockwise makes a lot more sense, but then what's the lockring for?

    Confused...

    I would guess that anti-clockwise would unscrew the sprocket. Reason being that the sprocket would continue to tighten from the pedal force and the lockring is reverse thread to prevent the sprocket from coming undone while reverse pedaling. A brilliantly simple safety device that causes sprocket and lockring to tighten against each other no matter what direction of force is being applied. So since you are using the whole weight of your body to tighten the sprocket when pedaling it may be a real brute to get off. If you do eventually get it off make sure to grease the threads when mounting the new sprocket and lockring. I would offer to help but being 6000 miles away I may be a bit late.
  • gtvlussogtvlusso Posts: 5,112
    Okay the deal is:

    Sprocket gets tightened by pedalling forward and can be loosened by pedalling backwards - hence the lockring to prevent you looseining the sprocket on a downhill if you put any back pressure on.

    If the screwdriver and hammer has failed try jamming the sprocket in a vice and turning the wheel. Use WD40 or Plus gas anti seize/penetration fluid - soak it overnight in it - then try again.

    If it still won't budge, you are looking at cutting the sprocket off, can be done with a hacksaw, but personally, the ever faithful angle grinder, metal cutting disc and a vice has done it for me.....Worst case scenario!

    Take it to your LBS and they should sort for you if you are worried about doing this.

    As for a new sprocket - plenty of coppaslip or copper grease on the threads will ensure that it does not seize on again.....
  • edhornbyedhornby Posts: 1,780
    fwiw I've tried the stand on the pedals method and it doesn't work, you can't get enough force without skidding the back wheel or toppling over like an eejit

    GTVlusso is right about the bits of wood and a vice method, after that it's off to the lbs and batting the eyelids (this will work for you and not me :) )
    "I get paid to make other people suffer on my wheel, how good is that"
    --Jens Voight
  • lost_in_thoughtlost_in_thought Posts: 10,563
    Thanks everyone!

    I will attempt the chainwhip method again, and if that doesn't work I've discovered this on t'interweb as an alternative that may give me more leverage - do you think I'd damage the wheel doing this?

    http://www.roadcyclinguk.com/news/article/mps/uan/2846

    And if all else fails, it's batting eyelids at the LBS!
  • crankycrankcrankycrank Posts: 1,830
    ^^^^^^That looks like an excellent way to gouge your chainstay and BB as well as your spokes if the chain comes off. Proceed with caution!!! You could also recruit a friend to hold the wheel while you stand on the pedals and pedal backwards or if the friend is packing a few more stones than you have them do the pedaling.
  • lost_in_thoughtlost_in_thought Posts: 10,563
    Can I just let you know that I got the damn thing off... Duck Oil is fantastic at loosening stuck things!
  • _Brun__Brun_ Posts: 1,740
    Thanks for the tip. I've never thought of ducks as particularly oily. How many did it take to free the sprocket?
  • biondinobiondino Posts: 5,990
    Have you never cooked with duck fat? Nom!
  • lost_in_thoughtlost_in_thought Posts: 10,563
    Nom indeed...

    Also, I forgot to mention, it unscrewed the normal way... ie pedalling forward would have loosened it.
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