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Crank Arm Thread Gone

  • 20-02-2021 4:04pm
    #1
    Registered Users Posts: 79 ✭✭ choicer


    I must have not correctly installed my left-hand pedal and it fell off a few weeks back.

    The threads within the crank arm are badly worn. The threads on the pedal are fine.

    Has anyone repaired their own crank arm? I've seen videos on a Unior kit but not sure you can get it, or something similar, in Ireland. Or, is it better to ask a bike shop to repair?

    Its a Claud Butler Exp 1.0 and Shimano Crank.

    Thanks!


Comments

  • Registered Users Posts: 29 MrFireCoalMan


    Check out Helicoil kits. They get used for the likes of stripped spark plug thread etc, might be worth a look. Hope this helps.


  • Registered Users Posts: 3,428 ✭✭✭ TheBlaaMan


    Depending on whether it is the drive side, or non-drive side, and the version (Sora, Tiagra, Ultegra etc) a replacement arm might be worth looking for .........?


  • Registered Users Posts: 289 ✭✭ f1000




  • Registered Users Posts: 6,548 ✭✭✭ Eamonnator


    O.P.
    Is this similar to your bike?

    https://claudbutler.co.uk/product/exp-1-0/


  • Registered Users Posts: 2,700 ✭✭✭ Type 17


    If it's a square-taper crank (or even a not-too-expensive Hollowtech one), most decent LBSs will have a few spare used ones (people get a whole new chainset when the rings are worn, so the LH crank is replaced). Cheap new (probably non-Shimano) ones are also available as a part.

    Tell them it's a Shimano, so they know to check if the one(s) they have have the square-taper hole 45 degrees from the line of the crank arm, not zero degrees (many other makes).

    Call and ask them if they have one (save a visit 'cos of Covid).


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  • Registered Users Posts: 79 ✭✭ choicer


    Eamonnator wrote: »
    O.P.
    Is this similar to your bike?

    https://claudbutler.co.uk/product/exp-1-0/

    That is the bike.


  • Registered Users Posts: 79 ✭✭ choicer


    TheBlaaMan wrote: »
    Depending on whether it is the drive side, or non-drive side, and the version (Sora, Tiagra, Ultegra etc) a replacement arm might be worth looking for .........?

    TBH, I've no idea what drive sides are.


  • Moderators, Sports Moderators Posts: 42,365 Mod ✭✭✭✭ magicbastarder


    it's non-drive side, as you mentioned it's the left hand side. 'drive side' just means the side all the gearing apparatus is on.


  • Registered Users Posts: 79 ✭✭ choicer


    it's non-drive side, as you mentioned it's the left hand side. 'drive side' just means the side all the gearing apparatus is on.

    Ah right, thanks! I assumed that but better to be safe than sorry.


  • Registered Users Posts: 5,341 ✭✭✭ LollipopJimmy


    Anybody else open this thread wondering why the mods deleted a thread about crank arms?


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  • Registered Users Posts: 3,770 ✭✭✭ MojoMaker


    Yep, I did :)


  • Moderators, Sports Moderators Posts: 42,365 Mod ✭✭✭✭ magicbastarder


    i hadn't spotted that.
    if i deleted this thread, would we have 'crank arm thread gone thread gone' thread?


  • Registered Users Posts: 1,902 ✭✭✭ Paul Kiernan


    Are we any closer to working out what exactly the OP is looking for (BB type, crank model, colour, size, etc.)? I might have one lying around in the garage!


  • Registered Users Posts: 79 ✭✭ choicer


    Are we any closer to working out what exactly the OP is looking for (BB type, crank model, colour, size, etc.)? I might have one lying around in the garage!

    Howdy. Its a left side pedal arm for a Claud Butler Exp 1.0. From looking at the spec its this: Shimano 170mm Alloy Crank, 48-38-28T Chainrings

    But I'm also wondering if I can just repair the existing arm rather than replace it. I haven't used the bike as much as I'd like so the arm is in good condition, bar the threads gone.


  • Registered Users Posts: 8,616 ✭✭✭ grogi


    choicer wrote: »
    Howdy. Its a left side pedal arm for a Claud Butler Exp 1.0. From looking at the spec its this: Shimano 170mm Alloy Crank, 48-38-28T Chainrings

    But I'm also wondering if I can just repair the existing arm rather than replace it. I haven't used the bike as much as I'd like so the arm is in good condition, bar the threads gone.

    You can repair it and I really appreciate the non-consumptionism attitude, but it will be much more hassle and probably cost than a simple replacement.

    Click

    Repair makes sense when you have vintage or high performance cranks, not the simplest square tapers.


  • Registered Users Posts: 6,627 ✭✭✭ cletus


    As above, you can repair the threads, and the easiest DIY method would be to use a helicoil kit. However, if you don't have the kit, or drill bits, taps etc, the outlay is probably more than the cost of a crank

    *Edit* had the reply window open for a bit before I posted, and grogi got there ahead of me


  • Registered Users Posts: 1,902 ✭✭✭ Paul Kiernan


    I presume it's square taper (not hollowtech)? In square taper each pedal bolts on to a central spindle. In hollowtech the spindle and drive side arm are all one piece, which slides through the bottom bracket and the lhs crank then bolts onto that using two small pinch bolts.

    Your best bet is probably to just buy a cheap one like the one referenced above for 19 euro. You will probably need a tool to replace it though!


  • Registered Users Posts: 5,341 ✭✭✭ LollipopJimmy


    I like the idea of repair but they are usually quite soft and the repair may not last. Replacement will be cheap and quite easy.


  • Registered Users Posts: 6,548 ✭✭✭ Eamonnator


    choicer wrote: »
    Howdy. Its a left side pedal arm for a Claud Butler Exp 1.0. From looking at the spec its this: Shimano 170mm Alloy Crank, 48-38-28T Chainrings

    But I'm also wondering if I can just repair the existing arm rather than replace it. I haven't used the bike as much as I'd like so the arm is in good condition, bar the threads gone.

    I don't think, it would be worth the time or money to repair it.
    I reckon you should be able to get a replacement in your local bike shop.


  • Registered Users Posts: 2,700 ✭✭✭ Type 17


    Totally pointless trying to repair the thread on the old one - at this price point they are almost a consumable (in fact shops sell the whole chainset when the teeth on the (non-removable) rings is worn).

    It looks like a Shimano FC-M311, which is linked to in post 4 above. LH cranks for this come in around €20 in your LBS (I've sold perfectly fine used ones for €10).

    Make sure you get one the same length - almost certainly 170mm, but match the old one - could also be 172.5 or 175mm but unlikely at this price-point.


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  • Registered Users Posts: 6,548 ✭✭✭ Eamonnator


    O.P.
    I've just had a root in my spares box.
    I have an F.S.A. Tempo square taper left side crank arm 170mm.
    I have a suspicion, that it will do as replacement for yours.
    If you can post a photo of your crank arm or if anyone else can confirm, that it'll work, You can have it F.O.C.


  • Registered Users Posts: 2,700 ✭✭✭ Type 17


    Unfortunately, FSA is one of the brands that has the square-taper hole at zero degrees to the line of the crank arms, whereas Shimano is one of the brands with the SqTa hole at 45 degrees, so if you mix them, the crank arms will be at 135 degrees (instead of 180 degrees) to each other. Nice offer, though.

    20200916-011_1024x1024.jpg?v=1600317989

    CC-DEORE170CRANK.jpg


  • Registered Users Posts: 6,548 ✭✭✭ Eamonnator


    @Type 17
    Mine is different to that one. Mine seems to have the same profile as the Deore one, that you reference. I'll try to post a photo in a little while.
    I can't remember where I got this. I think it may have been on a Peugeot 653, that I bought here to renovate.


  • Registered Users Posts: 6,548 ✭✭✭ Eamonnator


    This is the one I have.


  • Registered Users Posts: 2,700 ✭✭✭ Type 17


    That'll be fine - note how the hole on the left is diamond-shaped, as we view it, rather than square shaped.

    Funny, most FSA stuff is square-oriented.


  • Registered Users Posts: 6,548 ✭✭✭ Eamonnator


    O.P.
    If you want this P.M. your details.
    I'm in Drogheda, so I guess, I'll have to post. I'll cover the cost.
    You can pass on the favour.


  • Registered Users Posts: 79 ✭✭ choicer


    Eamonnator wrote: »
    O.P.
    If you want this P.M. your details.
    I'm in Drogheda, so I guess, I'll have to post. I'll cover the cost.
    You can pass on the favour.

    Hi there. My apologies for not responding to this very kind offer before now. Personal life stuff happened and so my focus moved away from bikes for a time. However, I did manage to get it sorted but again, thank you so much for the kind offer.


  • Registered Users Posts: 6,548 ✭✭✭ Eamonnator


    choicer wrote: »
    Hi there. My apologies for not responding to this very kind offer before now. Personal life stuff happened and so my focus moved away from bikes for a time. However, I did manage to get it sorted but again, thank you so much for the kind offer.

    No problem.
    Glad you got sorted.


  • Moderators, Sports Moderators Posts: 22,089 Mod ✭✭✭✭ CramCycle


    For anyone who comes across this thread, I got a helicoil put in, no problem for 25 euro by my LBS. Considering the outlay and hopefully the few times I would need it, this was quite reasonable and well worth doing if you are in a rush or can't find a like for like replacement


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