BB30 chain set query

stevenb
stevenb Posts: 717
edited December 2012 in MTB workshop & tech
My bike has a shimano press fit BB.
Ive seen a BB30 chain set I like but want to know if it will fit or is it just shimano only for me?
Thanks

Comments

  • njee20
    njee20 Posts: 9,613
    Depends if you have Press Fit 30 or BB91?

    If its the Superfly then no, you can't really fit BB30 without bodging
  • stevenb
    stevenb Posts: 717
    njee20 wrote:
    Depends if you have Press Fit 30 or BB91?

    If its the Superfly then no, you can't really fit BB30 without bodging
    It is for the Superfly.......Oh we'll.
    I wondered what double chain sets there were about as I want to go from a triple to a double like the 2013 model is.

    How can I find out what BB size I have as countless searching has found me anything.
  • 02gf74
    02gf74 Posts: 1,171
    the internal diameter of the bearings in BB30 are 30 mm, as is the spindle.
  • stevenb
    stevenb Posts: 717
    Just foun info on the Park Tools website that says trek use different bearings with an internal diameter of 24mm allowing fitment of shimano hollow tech II chain sets.
    My upgrade choice to a double chain set is either an XT or XTR it would seem.
  • njee20
    njee20 Posts: 9,613
    Correct, Trek alu frames use press-fit 91mm bearing cups, the carbon frames just use bearings pressed straight into the frame. Either way they're designed for 24mm HT2 cranks, or you can get SRAM compatible ones.

    So you options for 'proper' double chainsets (as opposed to fitting 2 rings to what you have) are just about anything that's not BB30: SLX, XT or XTR straight swap or anything SRAM with a new BB/bearings.
  • stevenb
    stevenb Posts: 717
    njee20 wrote:
    Correct, Trek alu frames use press-fit 91mm bearing cups, the carbon frames just use bearings pressed straight into the frame. Either way they're designed for 24mm HT2 cranks, or you can get SRAM compatible ones.

    So you options for 'proper' double chainsets (as opposed to fitting 2 rings to what you have) are just about anything that's not BB30: SLX, XT or XTR straight swap or anything SRAM with a new BB/bearings.

    Thanks.
    I assume then that with swapping to another shimano chainset it's simply off with the old and on with the new.
    Does that then mean the new bearings would be needed for the SRAM chainsets due to the slightly different internal diameter that the cranks require?
    Cheers
  • njee20
    njee20 Posts: 9,613
    Spot on.
  • stevenb
    stevenb Posts: 717
    njee20 wrote:
    Spot on.

    Cool.
    Thanks for your help.
    8)

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