Crankarm thread stripped... what next !?

Discussion in 'Observed Trials Discussion' started by Sforzando, Jul 21, 2004.

  1. Sforzando

    Sforzando Guest

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    Has anyone ever had the thread stripped in a crankarm where the pedal screws in? I got my Onza T-Raptor back from its first service yesterday and after riding for a very short while my left pedal felt all wonky. It wasn't screwed into the crank arm properly, and on closer inspection there were metal shavings where you could see it had been stripped. Now the pedal won't screw in and tighten at all.

    I rang the bike shop and they say they didn't play with the pedals, which is fair enough - I don't see why they would need to take them off in a service anyway. Now I have to take my bike back to them (which is an hour drive, because they are the closest shop that sells trials bikes) and they might have to send the part back to onza so they can say whether its covered under warranty or not. He reckons the bike might be out of action for a week or more, otherwise they can look at re-tapping it or something like that which will cost me bucks. What a pain in the arse...

    Has anyone had a similar experience or know why this could happen ? I don't even ride very hard. I've had the bike just over a month.

    Thanks
     
  2. TTownJon

    TTownJon New Member

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    A couple months ago, my bike got stolen from the basement of my dorm. Turns out a couple drunk frat boys were riding around on it and security picked them up along with my bike. Anyway, next day when I got the bike back, the pedal threads were stripped in the same way as you described. It was probably my fault for not torqueing them enough, but who knows. Anyway, I have a set of FSA Vdrive Extremes, and FSA didnt even blink before warranteeing them - didnt even need the reciept.

    What kind of cranks do you have?
     

  3. Sforzando

    Sforzando Guest

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    They are just the Onza cranks which came with the bike. The pedals are the Onza VP458A.....According to the advertisement in MBUK they are "The Best Trials Pedal you can buy"
     
  4. xxxfr

    xxxfr RCP FABRICATION

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    if theyre saying that the cranks are the best pedal you can buy, you got more probs than stripping them out. anyway, pic up a helicoil (one that has a stop, so it can only go in so far) and a tap to fix....IF WARRETNY GIVES U A PROB....
     
  5. Triple Eight

    Triple Eight Guest

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    depending on how bad the threads are messed up, sometimes you can run a tap in from the back side of the crank and straighten them up enough that you can get the pedal back on reasonably tight. if that's the case, i would (blue) loctite them just as something additional. if not, id say your friend got lucky, and i wouldn't plan on getting a warranty. worth a try though.
     
  6. Cory

    Cory Guest

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    A helicoil will work well but the best fix would be a keensert. Any good machinist will know how to put one in. This type of insert is better than a helicoil because it is a solid steel thread instead of a threadform spring. Here is a link detailing the keensert.


    http://www.jergensinc.com/infodir/catalog.asp?GroupNum=302a

    Sorry if the link doesn't work directly, if not paste it into your browser

    Cory
     
  7. durkie

    durkie Member

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    this just happened to me a couple days ago. i took it to a machinist and he drilled out a larger diameter hole where the pedal threads were, placed a stainless steel sleeve in the hole (with a lip on the non pedal side of the crank to keep it from pulling through) and then tapped the inside of the sleeve with pedal threads. tightening the pedal pulls the sleeve against the crank and keeps everything solid. works fine and cost $20.
     
  8. goose

    goose New Member

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    yo durkie,

    that sounds like a really phat pedal thread replacement method. Nice:) Do you know if the machinist was able to buy the stainless steel insert, or did he turn it himself?

    goose
     
  9. Sforzando

    Sforzando Guest

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    I took the bike in yesterday and the guy in the shop said it was covered by waranty, which is cool. He put in a helicoil for me - said its stronger now than it was. What a champion. I just hope the right side doesn't go now...

    She'll be right.