Bottom Bracket Problem

Forums Mountain Bike Forum Bottom Bracket Problem

--
SHARES
  

This topic contains 4 replies, has 3 voices, and was last updated by  AlexJoker 1 year, 5 months ago.

  • Author
    Posts
  • #239887

    So my friend and I have been having the same issues with our mountain bikes recently. Both of our bikes started creaking/squeaking after we did a small jump(5ft/1.5m) and it’s really annoying. Our bikes are both hardtails(aluminium) and are worth $300 each. When we landed we heard a small crack sound and after a while the bottom bracket started with the sounds. We aren’t really sure what happened.

    Also our rear wheel is rubbing against the frame when we pedal hard. We are pretty sure it’s a bent frame.

    Is this because the bikes are cheap and don’t have the best specs or does this happen to every bike?

     

  • #239892

    Definitely does not happen to every bike. It sounds like you may have broken the frame. Inspect the frame in the bottom bracket/chainstay area, paying close attention to the welds, which are more likely to fail on lower-end bikes (lower manufacturing standards, lower quality material, lower end bikes not usually meant for jumps/drops and more aggressive riding, etc.) In any case the wheel definitely shouldn’t be rubbing against the frame.

    • #239897

      I just checked my bike and the frame is absolutely fine except the rear wheel part. Other than that there aren’t any cracks and the welds look just fine.

  • #239920

    For the creaking BB…  may just mean resetting the bottom bracket.  If you have a threaded BB’s, just pull the cranks and BB’s, clean ’em up, lightly grease the threads, and but them back in.  Torque those BB’s correctly!   If they’re press fit BB’s, well, same thing, except a little more care is required to properly extract and press in the BB’s.  In either case, you’ll need the right tools.  That usually takes care of the creaking BB nuisance.  What’s interesting that it happened to two of you.  Did you both by chance go through water?  A $300 bike (if newer) may not have the best sealed BB’s.  If they’re older used $300 bikes with better BB’s, their seals my have seen better days.

    Regarding tire rub…  Are you sure tires are rubbing the frame, or are they rubbing the chain under load?  If it is indeed frame rub, like Head Over Handlebars said, could be frame damage.  That’s sometimes actually hard to see unless the frame is placed under stress during inspection.  Cracked frames hide under paint!  I’d also look for wheel flex.  After a hard landing without rear suspension to absorb the impact, your wheels may have been tweaked enough to allow flex under load.  Again, if your bike is a newer bike for $300, it would be safe to assume the wheel set isn’t up to hard landings.

    • #239936

      Both bikes were new not used. No we didn’t go through water. Also the rear wheel is not seating straight in the frame. The rear wheel is closer to the left side of the chainstay that to the right.

      Pictures : https://imgur.com/a/8NzIDSe

RELATED TOPICS

You must be logged in to reply to this topic.