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self extracting crank arm bolts...

Discussion in 'The Shop' started by jonKranked, Mar 5, 2008.

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  1. jonKranked

    jonKranked Press Button, Receive Stupid

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    Ok... so I have an old set of XTR cranks that have Shimano's old self extracting bolts. The system is on an octalink BB. I was wondering if it is possible to replace the self extracting bolts with stand crank arm bolts (and if anyone has done this)? I get an odd creaking from the cranks occasionally when I pedal; I have tried a diff BB to no avail. This is about all I can think of that would cause it - other than the splines on the crank arms themselves being worn out.

    Thoughts?
     
    #1 -   Mar 5, 2008

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  2. Dartman

    Dartman Old Bastard Mike

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    The only part that makes them self extracting are the rings screwed into the dust cap threads and they don't come into play when the bolts are tight. When you unscrew the bolts they push against the rings to remove the crank. Other than that they are just regular bolts.

    You could try removing the rings and their washer with a pin spanner to see if they are causing the squeak. It's important for the washers to be there so the bolt slips easily against the ring.

    I'd take everything apart and give it a good cleaning, use teflon tape on the BB threads and then lube the BB splines and install the cranks. Use a torque wrench to 35-40ft/lbs on the bolts.

    Check the chainring bolts too. Might want to do that first since it's easy. :p
     
    #2 -   Mar 5, 2008
  3. r464

    r464 Turbo Monkey

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    Grease... tons and tons of grease.

    That is always the answer.
     
    #3 -   Mar 5, 2008
  4. jonKranked

    jonKranked Press Button, Receive Stupid

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    word. thanks for the heads up y'all. I'll also check the spider... since its one of the ones that's bolt on.
     
    #4 -   Mar 5, 2008
  5. caputo1989

    caputo1989 Turbo Monkey

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    Strip it/ clean it. Don't use tefflon tape. Greasethe threads, and spline. If it is square teper do NOT put grease on the taper. Check the frame for cracks around the welds especially at the BB area. Remove the pedals and lube the threads there too. If they are clipless pedals squirt some tri-flow on the springs. If the BB is Octalink make sure it is not wasted, chances are it is.
     
    #5 -   Mar 5, 2008
  6. Dartman

    Dartman Old Bastard Mike

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    12345
     
    #6 -   Mar 5, 2008
  7. jonKranked

    jonKranked Press Button, Receive Stupid

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    ...


    :lighten:


    It was a brand new BB that I tried, so that eliminates that possibility.


    Frame is fine, I didn't have this problem when I had other cranks installed on the frame, but I had this problem when I had these cranks installed on other frames, just now getting around to addressing it.


    Thanks for the advice tho :thumb:
     
    #7 -   Mar 6, 2008
  8. binary visions

    binary visions The voice of reason

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    My experience with the Shimano Octalink bottom brackets is that they are very prone to creaking unless you over-tighten them. I know it's not good practice, but I usually just torqued the hell out of the bottom bracket and it would go away. Came up with no other solutions, and believe me, I tried. Regular tightening of the BB was the solution.

    That's from 3 different frames and 2 different sets of Octalink BB/cranks. The self-extracting crank bolts are not the cause since they went missing for one of the installations and I used another set. As a matter of fact I never found a loose crank bolt to be the cause, it was always the bottom bracket backing out a little.

    Doesn't really help, I know, but at least you know you aren't the only one who has seen the problem :p
     
    #8 -   Mar 7, 2008
  9. Dartman

    Dartman Old Bastard Mike

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    I have that same XTR crank setup on my M1. I had swapped out the BB for the original XTR octalink BB with the lock ring on the left side. It has deeper threads for the chainguide boomerang. It has never creaked. I'm the only thing creaking on the bike. :p

    Unfortunately they are very hard to find now if not impossible.
     
    #9 -   Mar 7, 2008