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Bottom Bracket installation(6 posts)

Bottom Bracket installationacp
Mar 12, 2003 2:02 PM
How much force should I use to thread the BB on the frame?It seems as though it is pretty tight and I don't want to damage the threads on the BB or the frame. Yes it is the correct size BB.

Thanks
re: Bottom Bracket installationCalvin
Mar 12, 2003 2:38 PM
That is difficult to explain in a note. Some resistance is fairly common. Be sure you are not cross threading the frame. If it seems difficult to install, it may need tapping. It is common on a welded bike for the shell to become deformed. Make sure the threads have anti-seize or at least grease. In some cases loctite is appropriate.
If everything is clean, they should go in by hand.Kerry
Mar 12, 2003 5:41 PM
However, you still may need to clean the grit out of both the frame and BB threads to get to this state. If this is the first install, spin them in a way with lots of grease, take them out, clean everything and re-grease, push them in farther, and repeat until they go in smoothly.
A follow-up question...t-bill
Mar 13, 2003 9:32 AM
I hear a lot of talk about facing the BB. Does this need to be done on a new bike?
A follow-up question...russw19
Mar 13, 2003 1:39 PM
I would. Most companies paint their bikes as the last step. This often leaves paint on the inside threads of a bottom bracket shell as well as on the outside face of the shell. You should always prep a new frame to make sure things are assembled properly. You should always chase the bottom bracket threads, to make sure they are clean and even so you BB goes in properly, and you should always face the bottom bracket shell as well as your headset.

Facing a surface involves cutting away paint or material from the surface to allow both outside surfaces to be exactly parallel to each other so that the bearings of the headset or BB wear evenly and properly. It just insures that the bearings line up properly with each other so they don't wear out prematurely.

Russ
If you think it's going on hard, something's wrong.Spoke Wrench
Mar 15, 2003 7:11 AM
The most common problem with bottom bracket installation is likely to be crossthreading from trying to screw the cups in the wrong way, a buggered thread at the edge of the bottom bracket shell, or not having the bottom bracket exactly square to the frame.