Bicycle Mechanics - movement in BB

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : movement in BB


BrokenGlass
04-19-06, 06:10 PM
today while cleaning off my bike and inspecting it all, i noticed there to be some play in the BB. when crank arms are parallel with the ground, they will move back and forth slightly. i just replaced the crankset and when i looked the BB i didnt notice any movement, and it seemed to be in good condition still. is there a chance that it could just be loose, or is it shot? its a square taper if that matters.
thanks for any help.

the picture is while looking down on the bike.


DieselDan
04-19-06, 06:37 PM
Time to replace the BB cartridge, or replace the BB bearings.

cascade168
04-19-06, 09:32 PM
today while cleaning off my bike and inspecting it all, i noticed there to be some play in the BB. when crank arms are parallel with the ground, they will move back and forth slightly. i just replaced the crankset and when i looked the BB i didnt notice any movement, and it seemed to be in good condition still. is there a chance that it could just be loose, or is it shot? its a square taper if that matters.
thanks for any help.

the picture is while looking down on the bike.

If it's a cartridge type you need to replace it. If it's a cup & cone type, it may just need to be properly adjusted. How old is this bike? It would help determine the BB type if you can post some close up pictures of the ends of the BB. If you determine it is a cup & cone type, here is the adjustment proceedure:

http://www.parktool.com/repair/readhowto.asp?id=93


BrokenGlass
04-20-06, 07:09 PM
thanks for the replies. i think its a cup & cone type BB. heres a picture of the non-driveside of it from when i was replacing the crankset. i have more pictures than this one if youd like to see the drive side too. the bike is a 2003

sorry about the delay in reply. professors decided to pile on the work.

cascade168
04-20-06, 07:57 PM
thanks for the replies. i think its a cup & cone type BB. heres a picture of the non-driveside of it from when i was replacing the crankset. i have more pictures than this one if youd like to see the drive side too. the bike is a 2003

sorry about the delay in reply. professors decided to pile on the work.

What I see in that picture looks like a typical cartridge type bottom bracket. The giveaway is that it clearly has a 20_spline ring which is typical of cartridges. Plus, most bikes new in 2003 would have cartridge BBs. You can get a new one for $15-20.

BrokenGlass
04-20-06, 08:47 PM
thanks for the help. is replace the cartridges easy? i'm still a novice in bike repair but want to be able to do most of it myself in the long term. i ride everyday (well, when i dont have too much school work). basically i dont want to screw anything up and then be out of a bike for weeks.

cascade168
04-21-06, 05:40 AM
thanks for the help. is replace the cartridges easy? i'm still a novice in bike repair but want to be able to do most of it myself in the long term. i ride everyday (well, when i dont have too much school work). basically i dont want to screw anything up and then be out of a bike for weeks.

See this page for full instructions on how to replace a cartridge style BB:

http://www.parktool.com/repair/readhowto.asp?id=94