Raleigh Bottom Bracket Woes

[NigelBlakey]

My touring bike is an old Raleigh frame (originally with a 'Mercury' decal, now obliterated by re-spraying) with a non-standard thread in its bottom bracket shell. In the past the fixed cup (which in the Raleigh world had no outer flange) had dragged into the shell so tightening up the whole assembly inexorably. My bike shop forced in an oversized fixed cup with an outer flange that stopped the over-tightening but in the process trashed the fixed-cup thread. Accordingly it will no longer accept a modern sealed bearing and the axle runs on old-style ball bearings.
The triple chainset I have is an ageing Stronglight-80 for which replacement chain rings are no longer available. At some time in the future the teeth will wear to the point that the chain will start jumping. When that happens I will be stuck because modern triple cranks are designed to fit on a sealed bearing that has a recessed profile to allow the crank to be pulled inside the edge of the bottom bracket frame shell. To fit such a triple crank onto an axle long enough to keep the crank clear of the fixed cup would leave the outer ring too far from the frame for the front derailleur to engage it and it would not allow the chain to run in a reasonably straight line.
So, my bike shop has suggested sending the frame off to a frame builder to have the bottom bracket shell cut out and a new shell (with a standard thread) to be brazed on and (re)sprayed. That would allow a modern sealed bearing to be fitted with a modern triple chain set. Cost: about £70-£80 as opposed to a new steel frame-set at upwards of £400.
Something completely different would be to have a new rear wheel built with a Rohloff hub, and put a single chain wheel on the front, provided of course that I can get a crank compatible with an old style fixed cup.
Your comments would be appreciated, not however the suggestion that I simply spend a thousand pounds on a brand new bike!

[gaz]

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[Brucey]

in addition you can usually bond a fixed cup into a damaged frame using epoxy resin. Choose the right BB system and the bearings, axle etc can be renewed without disturbing it ever again. If it does have to come out, a liitle heat will soften the adhesive quite well.

cheers

[Bicycler]

http://sheldonbrown.com/raleigh26.html
Sheldon says that 26tpi Raleigh bottom brackets were normally 71 or 76mm. If yours is 71mm he says this threadless one works: http://store.velo-orange.com/index.php/ ... ckets.html