For square-taper aluminum cranks:

When my drive-side crank is in the 12:00/highest position and the non-drive side in the 6:00/lowest position, there is slight play between both cranks (it rotates transversely/outward about 1mm) It's only in this one spot. Is this a bottom bracket going out? Last time my BB went out it was sliding side to side.

I've tried tightening the crank bolts but they are snug.

  • can you feel this play with the cranks removed from the spindle?
    – Paul H
    Commented Jan 10 at 20:41
  • Is this an open/loose bearing setup? I'd suspect wear in the cups/cones. Maybe worth upgrading to a cartridge-based BB.
    – Criggie
    Commented Jan 10 at 21:41
  • @PaulH I haven't removed the cranks. Currently on tour and don't want to make things worse till I'm near a city. If there is play, what does that indicate?
    – Laoshi
    Commented Jan 11 at 4:38
  • 1
    @Criggie I believe it is a cartridge. interlocracing.com/shop/ird-qb-95-bottom-bracket-4057
    – Laoshi
    Commented Jan 11 at 4:41
  • If you’re on tour, there’s nothing to be done but ride to the nearest shop and have them assess it.
    – Paul H
    Commented Jan 11 at 5:58

1 Answer 1


sounds like worn Bottom Bracket /crank bearings.

  • 1
    Welcome to Bicycles SE. We're looking for answers with more detail. Please consider editing your answer to explain why you believe the problem is worn bottom bracket bearings. A short, one-line answer like this is likely to get downvoted, flagged for moderator intervention, and possibly deleted.
    – jimchristie
    Commented Jan 12 at 14:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.