Bottom Bracket misery

deank said:

Hello,

The bottom bracket thread in my pace rc200 mountain bike frame has given up the ghost. Whilst investigating a creaking problem it looks like I've managed to cross thread it and now the bottom bracket will not tighten fully without slipping.

I am wondering what my options are. I love the frame and don't want to replace it. Are there any bottom brackets on the market that do not require a thread in the frame?

Any other alternatives? My bottom bracket unit is shimano BB-UN72.

Regards,

Dean

If it's totally buggered, english threads can be rethreaded to the larger Italian thread. Your BB choices will be more limited. Mavic may still market a BB that requires no threads. But the frame has to be specially preped for it.Check with Sheldon Brown at www.harriscyclery.com

deank said:

Hello,

The bottom bracket thread in my pace rc200 mountain bike frame has given up the ghost. Whilst investigating a creaking problem it looks like I've managed to cross thread it and now the bottom bracket will not tighten fully without slipping.

I am wondering what my options are. I love the frame and don't want to replace it. Are there any bottom brackets on the market that do not require a thread in the frame?

Any other alternatives? My bottom bracket unit is shimano BB-UN72.

Regards,

Dean

Are you sure the frame is stuffed, or is it the BB?

I thought I'd done the same thing last week, also with a UN72, on an alu frame, but it turned out that I had slightly flattened thread on the BB.
UN72s have alu cups.

boudreaux said:

If it's totally buggered, english threads can be rethreaded to the larger Italian thread. Your BB choices will be more limited. Mavic may still market a BB that requires no threads. But the frame has to be specially preped for it.Check with Sheldon Brown at www.harriscyclery.com

Thanks for the response boudreaux. By 'specially prepared', do you mean I'd need to take it to an actual engineering firm or something or would a bike shop be able to do this. What sort of preparation is it?

nutbag said:

Are you sure the frame is stuffed, or is it the BB?

I thought I'd done the same thing last week, also with a UN72, on an alu frame, but it turned out that I had slightly flattened thread on the BB.
UN72s have alu cups.

Yep, it's the frame all right 🙁

deank said:

Thanks for the response boudreaux. By 'specially prepared', do you mean I'd need to take it to an actual engineering firm or something or would a bike shop be able to do this. What sort of preparation is it?

The Mavic threadless BB requires the faces of the BB shell be beveled to accept the matching beveled lockring on the BB unit. Not sure the average shop would be set up to do it.Same goes for rethreading to Italian.Both are probably best left to at least a qualified frame builder.

I have a similar problem actually
I've been overhauling a really nice old (1979) kuwarha... or something like that.

The bottom bracket threads on the lock ring side (non drive side) are not completely stripped, but they are damaged pretty bad it seems prevent the bearing cup to thread all the way in.
I assume this is a pretty standard right hand thread.

Can anyone give me any suggestions?
I'd like to try and save the frame if possible, I only paid $20 for the bike, but it's the first bike I've sat on in a long time that actually seems like it was built for my legs (25" frame). Everything is built really well except for someone at one point installed caged rollers in the BB and they eventually rusted to nothing..and that's when i discoverd the damaged threads.

Need help
Thanks