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83mm Chainset in 68mm BB frame

BG2000BG2000 Posts: 517
edited April 2013 in MTB workshop & tech
I'm just putting together old bits to make a complete bike. It'll be a slight bodge, but decent bits, i.e. Cove frame, RaceFace Atlas chainset

The Atlas chainset is the FR version designed for 83mm BBs. With my BB cups fitted, it's set up as 73mm. There is enough thread to put 5mm of spacers inside each cup to spread it out to 83mm, but I'd rather not do that. Does anyone know of 5mm spacers that can sit on the chainset axle, between the crank arms and BB bearings ?

What alternatives do I have ?

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    Space the axel not the cups. What chain line are you getting?

    I would not bother though.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • BG2000BG2000 Posts: 517
    Thanks for the reply.

    I'm not fussed about the chainline, as this bike is mainly to drag the kids around in a trailer. :lol:

    And I'll only have one chainring up front, so FD alignment isn't an issue. I realise it might give a 55mm chainline, but I'll live with it.

    It's worth me bothering in that I've got enough decent parts to make a bike, without having to spend extra money. It's either that of these bits sit around in the garage for eternity.

    Do 5mm axle spacers actually exist ? I realise this isn't an approved method, but it'll do for the gentle riding this bike will get used for.
  • nicklousenicklouse Posts: 50,675 Lives Here
    Engineers shops exist.

    You are looking at something not normal so don't expect to find solutions in the normal places.

    Clamping width is critical on the RF crank design.

    Spacing out he cups reduces the thread in the BB. Limited options.

    Tbh I bet you would get more for the cranks and buy some cheap HT2s.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • BG2000BG2000 Posts: 517
    Cheers Nick - they're odd cranks unfortunately. The LHS is a FR, and the drive-side is AM, and the latter needs a good dose of loctite to stay put ;)

    I know what you mean about the RF clamping width....it's got to be right, which makes what I'm doing all the riskier.

    I've currently got a cartridge bearing sat on the axle each side (they're exactly 5mm width) so I know it works. I'll see what options I've got from a machine shop.

    I did say it was a bodge didn't I ?!
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