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  1. #1
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    Stripped Suntour Cranks

    If you could only hear the long string of profanities that just escaped my mouth!

    I'm working on cleaning and tuning up my old GT, which I've given to my son. In order to give the chainset a good cleaning (which it requires) I decided to take it off. No problem, right?

    I threaded the crankpuller into the old SR Suntour CR210 PFF. No problem. I started to tighten up the stud, and I was thrilled when it actually started to move. I'm a woman, and not a strong one at that. I was very pleased that I wasn't going to have to call one of the boys to strong arm it for me.

    Instead of popping off the crank, it stripped out the threads! Big problem! The thing is on there so tight that the threads don't have enough fortitude to support the removal of it. Wow.



    It didn't loosen at all, so I can put everything back together for the time being, and it will be safe. However, I have a new chainset coming for this bike (Shimano Alivio M410 . . . which I think will work with the BB on this bike). I need to figure out how to get the old one off.

    Even if I can't do it myself, hopefully a bike shop can.

    Suggestions?
    Know your limitations, and then defy them.

  2. #2
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    I assume a sqare taper?

    Unless the crank has defective material, the removal thread on the crank should suffice to pull several tons worth of freight. This is very resistant thread and at all times I have seen them damaged was from cross-threaded tools or very shallow insertions.

    Clean the crank removal socket and see if there are any threads left. Usually there are.

    If the thread is really totally gone, then the easiest solution is to simply thread the crank bolt back, loosely, and ride the bike for an hour or two. This usually causes it to come loose.

    Other means of removal require a shop to do and usually involve heat and/or bearing removal tools.

  3. #3
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    Yeah, a bearing puller is the easiest solution, especially if you don't care about the old crank. Most shops should have one.
    I'm a member of NSMBA and IMBA Canada

  4. #4
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    Thanks, folks.

    From what I've been reading online, what happened isn't unheard of for these old (garbage) SR Suntours. One help thread that I read indicated that this should almost be expected from them. While that may be an exaggeration, at least one person has seen it often enough that I don't particularly feel to blame or embarrassed.

    Yes, it is a square taper, and the new chainset is supposed to be square taper as well. There are around 1/4 of the threads left.

    The riding it to loosen it trick is a great one! I don't want to risk going at it again with the puller: for fear that I'll eliminate the remaining threads. I'd like to leave the threads for the bike shop in the event riding it doesn't work. There are two shops that I deal with. I'll call ahead to see if one of them has a bearing puller: if it needs to go into the shop.

    Thanks again! I feel a bit better now.
    Know your limitations, and then defy them.

  5. #5
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    An update on my dilemma.

    After trying to loosen the cranks by riding, and then by trying to remove them with a gear puller, and then bashing them with a mallet (I didn't expect that to work, but it sure felt good!). . . what finally worked in the end was fire.

    As a final act of desperation, I picked up a cheap propane torch, and heated the cranks until they were far too hot to touch.

    They fell off.

    The new cranks were installed on the old bottom bracket, and they work great.

    Thanks again!
    Know your limitations, and then defy them.

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