Question about my shell threads?
 

Hey guys I'm new to this forum and my first post so I thought what better place to go ask for help. :D

First I'll give you some of the background on my repair, for a while my bike has been crunching, creaking, and creaking near the BB area. I eventually figured out it was the BB and removed my cranks with the a bottom bracket tool and bought a new BB. The old BB removed very cleanly from the shell, I cleaned the threads of the shell with a brush and they looked nice to me. When I went to screw in the BB on the drive side (with grease) I do two full revolutions by hand then it just stops in its place. The threads looked very clean to me so I was surprised. If I can't hand tighten it I thought that I shouldn't try to force it to thread with a wrench. Don't worry about the measurements on the BB they are all correct so this wouldn't be the problem on my frame. I was curious about the non-drive side, so I took the cup of the new BB and it screwed by hand like BUTTER, like its supposed to. I also tried to screw in the OLD BB back in and its stops at the same exact point as the new one. Do I need to take my bike to a LBS to have the threads chased? I do not see any other options but I am welcoming any suggestions because I do not know a whole lot. If you do think that they need to be chased and have done it before, give me a ballpark price of how much is cost you to get the job done.

Thanks.

The drive side is normally reverse-threaded. It would be helpful to give the make/model/year of your bike and the model BB you are installing. You are absolutely right not to force anything.

Your local bike shop can determine the thread pitch of your shell and ascertain if you have the right BB.

If the old bb unthreaded and rethreads in smoothly it not likely the frame's threading is at fault. It's more likely the new bottom bracket's threads are misshapen or rough.

You were right to be careful and go slow. Bottom bracket threading is very fine and it's VERY EASY to cross thread one if you're not careful.

Sometimes though, the threads on the BB are lousy and you have to give it some force. Try installing the old BB again. Does it go in smoothly? If so, your frame is fine. When installing the new BB, be absolutely sure you have it on straight, then give it the force required to tighten it up.

Sorry to mostly repeat what HillRider said, my main point is to avoid cross-threading the BB.

I know you said not to worry about sizes and such, but a mismatch in threading *is* a possibility. Most recent bikes with threaded bottom brackets use English threading (1.37 inch, 24 threads per inch), but there are other standards out there. If you've got an older bike -- especially if it's French, Italian, or a Raleigh -- then there's a good chance a common English-threaded bottom bracket won't fit.

...but if that's not the issue, sometimes it's just a tight fit. The last bottom bracket I installed wouldn't thread in easily by hand. It went on smoothly without excessive wrench force, though.

Well, the OP said the non-drive side cup threaded in with no problems so the probability of the frame being anything but English threaded is almost non-existent.

Are the 2 revolutions smooth before it stops ? Greased threads ?
Did you try "forcing" it by hand ? Get a good grip by hand and give an extra oomph. Maybe just a burr in the frame.

I assume you're turning the right direction, counter clockwise to install, otherwise I doubt you'd get 2 revolutions.

Yes they are smooth and greased and I am turning counter clockwise on the drive side. It just stops every time and is REALLY hard to keep turning.

II don't generally notice thatI've crossed the threads until I'm at least six revolutions in. Haha I think you need to apply some elbow grease, if you know what I mean.

The thing about cross threading is that it leaves filings behind. Snug it in by hand, then use your tool to move it a couple more revolutions. Now back it out and inspect the threads and bracket cup. If it's clean, reinsert and take it a bit further. It'll start moving soon enough

Thanks my friend, I was being overly cautious, but once I went passed that burr in the threads with a wrench it went through perfectly thanks again to everyone in the forums for helping me out.