loose bb

veb

New Member
my bottom bracket works itself loose , then amazingly after another ride has tightened again with no movement at all.This has happened more than once, so what do you reckon?
 

e-rider

crappy member
Location
South West
A pixie is entering your shed at night with a very large BB tool - impossible!
 

Globalti

Legendary Member
When you say BB, presumably you mean the bearing cups screwed into the bottom of the frame? They are handed, with one being a reverse thread, the idea being that they should self-tighten. However they shouldn't be loose in the first place and the longer you allow this to go on, the more the threads will wear and the more sloppy the fit will become and the more difficult to fix.
 
OP
V

veb

New Member
its possible alright, and no pixies involved. Your right globalti its the bearing cups that i see the play in, they're fine at the moment after 28 miles this evening.
 

Globalti

Legendary Member
Get them sorted though. If nothing else, tighten them in with a gentle grade of threadlock. I can't advise but there must be a special assembly compound for this job. If you continue riding with them loose you risk damaging the frame irrevocably; they will self-tighten but not to the same torque as they need to be properly fitted.
 

Steve Austin

The Marmalade Kid
Location
Mlehworld
Remove the cups and lightly grease them. then tighten, until its quite tight, as tight as it will go with just using arm strength. if it loosens off again, you need to tighten some more.

You could use some threadlock (i use red) but its not really needed unless your bb is italian
 

Manonabike

Über Member
My BB requires a 50 - 70Nm which is quite a lot of pressure. I have to use a long spanner to get that kind of pressure.
 

gbb

Legendary Member
Location
Peterborough
Had something similar on a cheap BSO i was doing for someone. BB was loose, so adjusted it up...only for it to come loose again in a day :smile:
BB shell was cream crackered. ( at that point we agreed it was a write off, so i suggested welding the cup and cone type BB in place...that didnt work very well either) :smile::biggrin::biggrin:
 
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