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BB install questions(4 posts)

BB install questionsgirodebirdman
Aug 23, 2001 12:12 AM
Hi. I had lots of difficulty installing a BB on a frame today. The BB was Ultegra, Italian thread, onto a used Aluminum frame (new to me). Anyways, should I have had this frame tapped before I installed the BB? One had been in there recently, but there must have been some crap in the threads, because I had to constantly thread-unthread-rethread a bit more to get the cups in (I used a bit of lube to help it along). It is now installed correctly, after much effort. Should I pull it apart and retap it though, to clean out the threads and prevent future siezure when I remove the BB? I figure I basically chased the threads with my cups (the hard way, there was definitely hard residue in there) For some reason, I only though retapping was necessary on a cross threaded frame, not one that was new 6 months ago and recently had a BB installed. Will my BB now get stuck, or am I good to go? Thoughts?
What lubricant did you use on the threads??Cima Coppi
Aug 23, 2001 5:05 AM
Also, how difficult was it to pull the old bb out? If I were in this situation, I'd pull the BB again (after being fully installed and carefully inspect the threads on both the BB shell and the cups. If they look fine, clean out the BB shell once more with a wire brush and compress air to get any remaining gunk, metal shavings, etc. from the shell, and re-install using anti-sieze for the lubricant.

A BB cup should install very easily until you get it near the shell. Assuming the threads were correct, the fact it was so difficult to install yours means one of two things; the threads were not clean, or it was cross threaded. Check it out, esp. to make sure your new bb does not get siezed into the shell.

Good luck,

CC
What lubricant did you use on the threads??girodebirdman
Aug 23, 2001 10:23 AM
I used Finish Line chain lube (the same thing I use when threading a steerer tube with a die). Anyways, I definitely did not cross thread the shell, as the BB went in by hand-turning until it was halfway installed, plus now that it is fully installed, the line is correct. What it looks like is that perhaps the old cups weren't as deep as the ones that it was replaced by, therefore the crap in the threads. I was just hoping that by putting in the BB, and chasing the threads in doing so, I could avoid taking it to a shop and having them chase it for me. But if seizure will be a problem later down the road, then I will take it in.

Scott
What lubricant did you use on the threads??G
Aug 23, 2001 10:52 AM
I would recommend using thicker lubricant for the bottom bracket. I've used Finish Lines' white lubricant(it's a thick grease-can't remember the exact name). Now, I use a copper-based anti-sieze from 3M since I have a ti frame. Just my opinion.