Complicated BB Installation Question/Problem
OK this might get long winded....i attempted to install an X-Type Race Face BB (External Bearing) onto my MTB today....I removed the stock Shimano Octalink with no problem....totally wiped the BB shell clean and regreased it. I installed the drive side BB cup into the frame no problem. Started screwing the non-drive side in and it wouldn't go in very easy....pulled it back out and tried again....went in a lot easier but not effortless...Pushed the left side crank arm on and then attached the right side with the crank arms.
The crankset didn't spin very well at all....would spin maybe one revolution and stop (with no chain attached). Started looking close at the BB cup on the non-drive side and noticed that the top of the Bearing-Cup was flush with the BB Shell but the bottom was about 1mm away from the BB shell. Major problem. So I pulled it all off and tried the left side BB Cup again and could not get it to line up flush on all sides of the shell.....what is the deal? Questions:
1. Could my BB threads be stripped out? If so is my frame worthless?
2. Does the fact that the cup is not in the shell square make the crank not spin freely?
Thanks for any help....as you can tell I am a little stressed.
Long haired freak.
You cross threaded it. Your frame is not completly worthless, because it could probably be tapped by a bike shop depending how bad it is.
Also because it is cross threaded, that is probably the reason its not spinning freely. But I could be wrong.
yea, i would suspect the threads need re-tapping. that would cause friction that is unwanted. take it in to the Mechanics and let them look at it.
Looks like you've cross-threaded the drive side cup. Have your local bike shop ream out the threads with their special tool (bottom bracket taps) for a small cost and hopefully you will be able to install the bb properly. If you have trashed the threads then a specialist repaired (like Argos in UK) will be able to rescue the frame for you by either recutting the threads oversized or installing a dsleeve. This would be expensive!
I doubt it's cross-threaded, it if was you wouldn't get the threaded cup more than 1/3 of the way installed before it would bind solid and tear the crap out of the threads.
Most likely, the bottom bracket shell in your frame just needs to have the threads chased and the ends faced. Many production line frames have issues like this when installing a new bottom bracket. Just go find a good LBS with the proper tools and have them take care of it.
As a side note, don't expect your new crank to spin around like a wheel - in fact, it shouldn't. Just as long as it spins without binding you are golden - bearings are packed with thick grease and seals are tight (like they should be).
Hey-Thank you all so much.....I was seriously worried that my frame may be trashed. By the way...how much should I expect to have the BB chased and faced?
Not sure, I have all my all tools. Tools are expensive so maybe...$25?
Originally Posted by SerialLadyKillr