Chainset Repair

Pross
Pross Posts: 43,538
edited July 2010 in Workshop
I went to put new chainrings on my old Ultegra 600 chainset a few months back and one of the bolts was seized. Having tried all the suggestions from people on here I still couldn't get it off and my father-in-law tried to hacksaw through the bolt. Unfortunately he got a bot carried away and started to cut into the spider, going about a third of the way through one of the arms. Firstly, is this likely to cause a problem or should the remainder be strong enough to cope? Secondly, is there an easy way (short of welding) to repair the damage? I've tried picking up a second hand Shimano square tapered chainset on ebay but they keep going for more than I would have to pay for a new budget one but if anyone has one lying around they fancy selling let me know. I had a clubmate who was going to let me have his as the crank on the non-chainring side broke but his cranks were 170mm whereas mine is 175mm :(

Comments

  • unixnerd
    unixnerd Posts: 2,864
    Lay the bike on it's side and very firmly support the rear of the bolt on something solid. Then thump the cr*p out of the top side with an impact screwdriver and hammer (tenner from Halfords, wonderful tool).
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  • balthazar
    balthazar Posts: 1,565
    I wouldn't consider using a crank which had been sawn a third through. The spider arms transmit considerable torque, and though a failure may not be catastrophic, it would probably be assured. You could use a chainset from any manufacturer – Campag, Stronglight, etc as well as Shimano: NOS kit from a few years ago is pretty freely available.

    FWIW, I've ridden a bike for months with a 170 crank one side and 175 the other without noticing. If it'll get you riding then take the offer and put a new chainset on later!
  • Weejie54
    Weejie54 Posts: 750
    If only your father-in-law had drilled it out.....
  • Pross
    Pross Posts: 43,538
    Weejie54 wrote:
    If only your father-in-law had drilled it out.....

    Thought of that but a bit tricky when the outer part of the bolt was free turning bit the inner was seized solid. I've seen just the thing on ebay - keeping an eye on it so hopefully I'll be sorted out soon. Failing that I'm going to get a cheap new compact chainset.
  • Wamas
    Wamas Posts: 256
    Sounds a bit like my father-in-law. You should see the mess of the bottom of the doors to my dining room when he offered to cut them down when I fitted hard wood flooring in the hallway.

    Anyway, back to your thoughts, I would definately replace them. You can get hold of a cheap second hand crankset and BB for about £35, or is this above your budget.
  • Weejie54
    Weejie54 Posts: 750
    Thought of that but a bit tricky when the outer part of the bolt was free turning bit the inner was seized solid.

    You stick an allen hey in a vice with about 5mm protruding. Put the chainring bolt over the allen key (hex end first) and drill from the other side.

    Bit too late now though...
  • beverick
    beverick Posts: 3,461
    Just buy a new spider?

    Bob

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