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  1. #1
    Senior Member tugrul's Avatar
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    Can non cross threaded pedals sieze to the point they rip the aluminum threads out?

    I just put a fair amount of effort (no additional leverage, just a 10" wrench) to remove pedals off a bike teetering on being too rusty to bother with, and on both sides the pedal threads took a fair amount of aluminum with them (cranks are Sugino VPs).

    Now I'm wondering whether I'm at fault for being too gung-ho about getting these pedals off before soaking them in ammonia or something (they never gave after the initial movement), or whether they were cross threaded to begin with. I've put waaaay more force into removing pedals before (me with a 6 foot pipe), and all that resulted in was a warm pedal.

    Have you seen a properly threaded pedals so seized it took some aluminum with it?



    As a side question, how much should I expect to get charged to have the cranks re-tapped? (I can thread pedals on, but not sure whether I feel good about it) Or should I just buy a set of Park TAP-6 taps for about $35 so I can be prepared and then this will never happen again

  2. #2
    Senior Member tugrul's Avatar
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    Pedals, bottom and top.


    DS Crank

    NDS Crank


  3. #3
    feros ferio John E's Avatar
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    That does not look good. Remember that the pedal shafts bear your entire drive force, and there is a natural torque moment which tries to rip them out of the cranks. If you promise never to stand/"dance" on the pedals, you can cautiously use those cranks awhile longer.
    "Early to bed, early to rise. Work like hell, and advertise." -- George Stahlman
    Capo [dschaw'-poe]: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger, S/N 42624
    Peugeot: 1970 UO-8, S/N 0010468
    Bianchi: 1981 Campione d'Italia, S/N 1.M9914
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  4. #4
    Senior Member clasher's Avatar
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    You could get a heli-coil put in for 1/2" pedals, but that limits your pedal selection, and might be more time and hassle than it's worth unless you have machinist friends.

  5. #5
    Insane Bicycle Mechanic Jeff Wills's Avatar
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    Quote Originally Posted by tugrul View Post
    I just put a fair amount of effort (no additional leverage, just a 10" wrench) to remove pedals off a bike teetering on being too rusty to bother with, and on both sides the pedal threads took a fair amount of aluminum with them (cranks are Sugino VPs).
    I bet the rust expanded the pedal axles to the point they were never going to come out without taking the cranks with them. I don't think there's enough material left in the crank to hold pedals adequately.

    My recommendation: toss it all out. There's nothing worth saving.
    Jeff Wills

    All my bikes.

  6. #6
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    Heli-coils, for sure. Done properly, they'll be better than new.

  7. #7
    Senior Member Iowegian's Avatar
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    Don't blame yourself, those were hopeless before you got to them.

    Heli-coils and a wire-brush mounted on a grinder for the pedals if it's worth it to you - or just toss the lot.

    And - I know you know this but some newbies may not - this is one reason why you always GREASE the threads.

  8. #8
    Reeks of aged cotton duck Hydrated's Avatar
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    It's called galvanic corrosion. When you put two dissimilar metals in contact they begin to corrode. They will eventually become basically welded together if you haven't taken precautions to prevent the corrosion. And when you try to remove the part, it just rips the threads right out. Pedal threads and spoke nipples always tend to be problem areas and should always get a dab of anti-seize compound.
    It is the mark of an educated mind to be able to entertain a thought without accepting it.-Aristotle

  9. #9
    Senior Member tugrul's Avatar
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    Bummer. Didn't know it could get that bad.

    It was a $5 Centurion Accordo, mid-80s sea green/gray two tone model. If there are any more surprises like this, it may just never see the road as a complete bike again.

  10. #10
    www.theheadbadge.com cudak888's Avatar
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    Ripped the pedals right out. That galvanic corrosion that Hydrated refers to is the same thing that keeps stuck seatposts bonded to many frames. These pedal threads give a pretty good idea as to the strength of such bonds.

    -Kurt

  11. #11
    rhm
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    multimodal commuter rhm's Avatar
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    Yup. I haven't had that specific (pedal to crank) problem, but on my folding bike, which is mostly aluminum, I've had several stainless steel fittings get so comfortably mated to aluminum that the same thing happened. Stainless... but not corrosion-proof. As said above, always grease the threads. And when you buy a new bike, take every every everything apart, and grease it all, and put it back together. Yes, that's a PITA, but the alternative (galvanic corrosion) is at least an equal PITA, fnot worse.

  12. #12
    Senior Member auchencrow's Avatar
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    It's not the first time I've seen pedals do that to a crank - all because someone ran them in dry.

    If you want to save the pedals, the best way is to get right and left handed 9/16 dies and run them back over the threads.
    - Auchen

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