Bottom Bracket Replacement

Mark N to Z

Hi, I have just noticed that my bottom bracket is loose and on closer inspection I have found that I have some damaged threads in the frame where the bb has been moving around.
I have stripped it all out and have two questions for you seasoned mechanics:

1) my bottom bracket is a Shimano BB-LP27 and the only reference I can find to the axle length is on the end of the shaft where "MM 11?" is stamped...I can't make out whether it's a MM110 or MM113.
I have measured the shaft which is 111.8mm long...does that constitute an MM110 or MM113 (I have used a vernier caliper to measure so it's deadly accurate !)...oh...for those of you working in Imperial...it's 4.4"

2) For my damaged threads, I have tried building up the threads with ptfe tape, a bit of a bodge-I know but shows promise!, anyone found a neat fix for this themselves ? I was trying to find a Swiss BB which should have a 0.5mm larger thread diameter (and is LHanded)..but without success ....or has anyone heard of a proprietary "recovery shell" which is slightly oversize to deal with such disasters?

I look forward to your wise counsel,

kind regards,

Mark N to Z

jeremy067390

ok i was just curious how many threads r damaged? i would seriously consider leaving it be if its not that many and finding a shop with this tool

http://www.parktool.com/products/de...48&item=BTS%2D1

chasing the threads and replacing the bb would be the best idea, especially if the threads on the bb r damaged, which i garuntee they r probably dulll from moving. nice new sharp threads would be best. try blue loctite too maybe. good luck

jeremy067390

by the way lots of frames r warranted for life

davebee

Disregarding Jeremy's reply because I can't udnerstand a word of it. Iz not kool 2 tlk n txt spk lik.

a) I have no idea about the shell width sorry. if you are upgrading the chainset wy not get a hollowtech II or X-0type system that has spacers to allow for any chain width. If not I would probably go for a 113 but that is just based on gut instinct.

b) for the stripped threads, take the bike to a GOOD lbs and get them to re-tap the threads. It is not worth purchasing the kit yourself as it costs £100s and you will likely only use it once or twice. This shouldnt be too expensive. If you take the old BB in, they will probably be able to offer you something similar, and may even install it for you at the same time. I wouldnt try to bodge the BB in because if it fails then it is end of ride.

jeremy067390

ok jerk wad. besides using bb for bottombracket u also used lbs, what did you do i didnt? oh sorry i used r instead of are i can see how small minded folk would have trouble understanding that code, tard