bottom brackets rethreading

gbnz · Post by **gbnz** » 13 Sep 2008, 11:01am

the bottom bracket mounting thread has finally failed on my favoured road bike, resulting in my being unable to install a new bottom bracket cartridge (It's a 2001 bike with an internal/cartridge bottom bracket)

the bottom bracket mounting is of 6061 alloy. the previous bottom bracket cartridge being fitted on a "bed" of epoxy" resin, due to insufficient thread remaining to fit the cartridge correctly

a replacement frame at R.R.P. is £350, a cost I'd prefer not to meet. however i find too much stress and movement exists to mount a bottom bracket cartridge purely on epoxy resin, as it creaks, groans and presumably will come adrift at some stage (probably when i'm 50 miles away from home, putting pressure on the pedals whilst ascending one of many hills)

does anyone know of anyone who deals with rethreading bottom bracket mountings on an alloy frame?

thirdcrank · Post by **thirdcrank** » 13 Sep 2008, 2:45pm

The solution for a steel frame once suggested to me by Ellis Briggs as an alternative to a new BB was a widish cut through the BB shell, queeze it together, braze it up and rethread.

I've no idea if that would work with alloy but it would cost nothing to ask a frame builder.

aesmith · Post by **aesmith** » 13 Sep 2008, 7:05pm

Years ago Dawes replaced my frame under warranty when the BB threads failed. What's the guarantee on yours?

rogerzilla · Post by **rogerzilla** » 13 Sep 2008, 8:31pm

Just get a bottom bracket that fits without frame threads (it's trapped between two lockrings instead). You should get the BB shell properly faced first, but any half-decent LBS can do this.

cambsos · Post by **cambsos** » 14 Sep 2008, 10:24am

Argos Cycles in Bristol do a permenant BB repair which involves a new sleeve being inserted.
Costs about 80 quid I think, might be worth giving them a ring or a look on the web

gbnz · Post by **gbnz** » 14 Sep 2008, 11:29am

Many thanks for the replies

I can see cutting and brazing would work on a steel bracket, perhaps not on an alloy one. Equally, the bikes too old, had too much use and probably one or two bodged repairs too many to fairly claim under warrenty

I'd heard of bottom brackets fitted via locknuts, however I'm seeking a repair of a more permanent nature I.e. one that'll allow future bottom bracket replacements to be undertaken, using standard parts. Argos Cycles seem to undertake some highly specialised cycle work, so I'll give them a shot, as a permanent repair is well worth paying for

While like most people I enjoy buying new, there is something particularly satisfying about keeping a fantastic bike running for another 10K. Having used the bike for an unaccustomed "commuting run" into town last week (Had to get to the bank prior to closing and my cheap town bike was punctured!), I had the equally satisfying (Initially disturbing) experience of leaving the bank to see my bike surrounded by the local hoodies

"Fab bike mate", "Where'd you get it?", "How fast does it go" (Tempted to reply, depends how fast you pedal). Appears you don't have to a cyclist to appreciate a decent bike!!