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BB30

cknellerckneller Posts: 22
edited December 2012 in MTB workshop & tech
Just bought a stumpjumper fsr frame with a BB30 bottom bracket. This is my first bike build so I would be going in ignorant regardless of which BB it was using!

I intend to buy the sram bearing kit which will give me the circlips, bearings, covers and spring washer. I'll also be buying a couple of 2.5mm spacers as the specialized assembly diagram shows.
(Page 4 on here http://service.specialized.com/collateral/ownersguide/new/assets/pdf/IG0276_revF.pdf)

The one thing I don't have and can't find for love nor money is the 84.5mm spacer for placing between the two bearings. Can someone with some experience in these BBs let me know if this spacer is actually required?

I can get one made up if need be but from what I can see it's only job would be to prevent breaking the circlips if the crank bolt was done up too tight. But surely just torquing this up to the manufacturer's recommended torque would prevent this?

Cheers all
Chris

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    first read the info on parktools.

    then think do you really want a BB30?

    there are lots of alternatives that can be run.

    so do you really want a 30mm diameter axle or not.

    if you do read the fitting info for the cranks you get and do some measuring.

    the info you have linked to is NOT BB30 but Speshs own 30mm cranks to work with the BB30 bearings.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • I had looked into the park tool info on BB30s and adapters but thought if the frame had been designed for a BB30, why not use a BB30 if they considered it the optimum solution.

    I had looked into running adapters though because of the amount of crankset options it opens up; many of which being cranks I would rather have. Do you know of any down sides to running adapters in BB30 bearings? Would this add a potential second point of rotation and wear?

    Thanks for letting me know about reading the wrong assembly instructions!
  • njee20njee20 Posts: 9,613
    Agreed, if the chainset you want is available in BB30 then get that.

    If it's not (ie Shimano) then there are an increasing number of adapters becoming available. When Spesh frames were OSBB rather than BB30 (slightly different shell width), they did their own adapters, I'd be more inclined to use Wheels Manufacturing or similar though, more durable.
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