Bicycle Mechanics - loose bottom bracket?

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View Full Version : loose bottom bracket?


2mtr
08-05-09, 06:12 AM
how do i know if i've got a loose bottom bracket?

i feel a sort of clunk and hear a dull ping once in a while when i lay hard on the right crank of my Crosscheck. it's the same thing i experienced a few years back with another one of my bikes -- a Long Haul Truker. when i brought the bike into the LBS that had assembled it, they said the BB had "worked loose."

this is a new Crosscheck which hasn't been adjusted since I picked it up. i would take it back in, but i'm pretty busy with work for the next few weeks.


Panthers007
08-05-09, 06:18 AM
Bring it back in. If you don't have the proper tools, or skills, to do this work yourself - you have no option but to take it to the shop it came from. They will honor the work under the warranty I assume the bike came with.

2mtr
08-05-09, 08:14 PM
yes, thank you. but: how do i know if i've got a loose bottom bracket?


wrk101
08-05-09, 08:30 PM
yes, thank you. but: how do i know if i've got a loose bottom bracket?
Park Tool site gives a great recap of bb adjustment including whether it is loose. Is there ANY play in the crank arms?

kaseri
08-05-09, 09:18 PM
As always, Sheldon has the answer...

http://www.sheldonbrown.com/creaks.html#bottom

Panthers007
08-05-09, 11:38 PM
Put your hand on one of the crank-arms. With the bike upright, try to push and pull the crank-arm toward and away from you - left and right as if you were viewing the bike from behind. Is there any play side-to-side? If yes - the bottom-bracket is loose. Or the crank-arm is loose. Got the right tool? Tighten the crank-arm bolt and try again. No got tool?....

"....- you have no option but to take it to the shop it came from."