Press-fit BB - what crankset? Will m970 XTR work?- Mtbr.com
Results 1 to 5 of 5
  1. #1
    Registered Dietitian
    Reputation: tommyrod74's Avatar
    Join Date
    Jul 2002
    Posts
    1,639

    New question here. Press-fit BB - what crankset? Will m970 XTR work?

    Got my new Superfly Elite hardtail frame last week, and built it up as a 1 x 10. I used my m970 XTR crankset (the one with the funny bearing preload collar) and realized pretty quickly that the preload collar won't work - it actually contacts the frame's BB shell since the bearings are pressed in flush with the shell. So I left the collar off, and tried again. Now the bearings would bind up when the arms were snugged on.

    The only way we could make it work was to leave the orange bearing shields OFF of the bearings, as this seems to relieve the binding pressure and the cranks can spin smoothly.

    None of these issues were encountered by my teammate - same frame, but XT crankset.

    Are there just some external BB - conceived cranksets that won't play nice with the press-fit systems? Should I try a different crank, or is my current XTR setup going to be OK? The bearings are fairly cheap, but I'd hate to ruin them regularly (they held up fine for 5.5 hours of riding this past week - dry conditions).
    Registered Dietitian, Cycling Coach, Ascend Nutrition and Coaching

    www.ascendthepeak.com

    www.facebook.com/ascendthepeak

  2. #2
    mtbr member
    Reputation:
    Join Date
    Jul 2007
    Posts
    453
    Shimano has fatal flaws when it comes to XTR cranks:
    M960 - 102BCD and 146BCD
    M970 - preload collar and special crank arm removal tools
    M985 - 88BCD

    The only XTR crank that seems to work normally is the M980 crank. It's pretty infuriating that Shimano didn't get punished in the marketplace for creating solutions in search of problems. I would sell your M970 and buy a M980 instead.

  3. #3
    mtbr member
    Reputation: brentos's Avatar
    Join Date
    May 2006
    Posts
    1,787

    Bb92

    What bottom bracket are you trying to use? I had a Shimano BB92 bottom bracket, on a press fit frame, and it didn't have any orange bearing seals. It worked great. Be sure you're using a Shimano BB92 bottom bracket.

    For example:
    http://www.universalcycles.com/shopp...s.php?id=33853

    The M970 is a great crank...no need to buy a new one.

    edit: I know Trek was using their own bottom bracket standard for awhile there (BB90), but I think they sold some bikes with M970 cranks, so if it has the BB90, Trek should have adapters available.

  4. #4
    Registered Dietitian
    Reputation: tommyrod74's Avatar
    Join Date
    Jul 2002
    Posts
    1,639
    Quote Originally Posted by brentos
    What bottom bracket are you trying to use? I had a Shimano BB92 bottom bracket, on a press fit frame, and it didn't have any orange bearing seals. It worked great. Be sure you're using a Shimano BB92 bottom bracket.

    For example:
    http://www.universalcycles.com/shopp...s.php?id=33853

    The M970 is a great crank...no need to buy a new one.

    edit: I know Trek was using their own bottom bracket standard for awhile there (BB90), but I think they sold some bikes with M970 cranks, so if it has the BB90, Trek should have adapters available.
    BB95 from what I can tell - the MTB version of the Madone's BB90. From what I can tell, not compatible with the Shimano press-fit standard.
    Registered Dietitian, Cycling Coach, Ascend Nutrition and Coaching

    www.ascendthepeak.com

    www.facebook.com/ascendthepeak

  5. #5
    i ride bikez!!11!
    Reputation:
    Join Date
    Aug 2006
    Posts
    485
    I'm pretty sure that you can get a small washer that goes between the seal and the bearing. Log into Dexter (or find someone who can) and find an exploded view of a BB95 frame that came standard with the 970 crank. They have come OEM before so it's definitely possible to make fit.

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.