Bottom bracket knocking

[Paul Bobby]

Any ideas about what to do about this would be greatly appreciated.

Have noticed a knocking/popping sound coming from the area of the bottom bracket. Getting worse over
the last few weeks- can practically feel
it. Knock occurs with every pedal revolution when the right foot hits 2-3 O'clock. More pronounced
when spinning at higher rpm.

Crankarms are tight. Not from the pedals (swapped pedals from another bike). Not chain related
(persists when spinning in my living room with the chain off the chainring).

 

[Mike Jacoubowsk]

> Have noticed a knocking/popping sound coming from the area of the bottom bracket. Getting worse
> over the last few weeks- can practically feel
> it. Knock occurs with every pedal revolution when the right foot hits 2-3 O'clock. More
> pronounced when spinning at higher rpm.

A knocking noise that's repeatable like that shouldn't be too touch to find. For starters, you
should grab each crank arm with one of your hands, and see if you can rock them back and forth
(laterally, perpendicular to the direction the chain moves). If you can feel it but not see where
it's coming from, have someone else help out by placing a finger on the area where the bottom
bracket spindle comes out of the frame... they should be able to detect what part's moving.

There really aren't all that many possibilities. If it's definitely coming from your cranks, and
it's not your pedals, then it's almost got to be either the axle within the bottom bracket (perhaps
shot bearings), or the bottom bracket assembly is loose on one side or the other (or perhaps both).
If it's a loose bottom bracket assembly, you need to remove both crank arms, loosen the bottom
bracket cup on the side opposite the chainrings, fully tighten the chainring side, and then tighten
the other.

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

"Paul Bobby" <[email protected]> wrote in message news:[email protected]...
> Any ideas about what to do about this would be greatly appreciated.
>
> Have noticed a knocking/popping sound coming from the area of the bottom bracket. Getting worse
> over the last few weeks- can practically feel
> it. Knock occurs with every pedal revolution when the right foot hits 2-3 O'clock. More
> pronounced when spinning at higher rpm.
>
> Crankarms are tight. Not from the pedals (swapped pedals from another bike). Not chain related
> (persists when spinning in my living room with the chain off the chainring).

 

[W A S A T C H]

"Paul Bobby" <[email protected]> wrote in message news:[email protected]...
> Any ideas about what to do about this would be greatly appreciated.
>
> Have noticed a knocking/popping sound coming from the area of the bottom bracket. Getting worse
> over the last few weeks- can practically feel
> it. Knock occurs with every pedal revolution when the right foot hits 2-3 O'clock. More
> pronounced when spinning at higher rpm.
>
> Crankarms are tight. Not from the pedals (swapped pedals from another bike). Not chain related
> (persists when spinning in my living room with the chain off the chainring).

Same problem happened to my bike. I took out the bottom bracket wrapped the threads in plumbers
Teflon tape and reinstalled. No knocking, clicking or popping

-N