[CR] Damaged BB fixes

(Example: Production Builders:LeJeune)

Date: Thu, 17 Dec 2009 15:53:26 -0500
From: "Wayne Bingham" <veloclassique@gmail.com>
To: <classicrendezvous@bikelist.org>
Subject: [CR] Damaged BB fixes

EDCO's Eccentric BB had steel cups, not alloy. This BB's primary limitation is that it requires 35mm clear to slide the unit in. On a damaged BB shells, that's not much of a problem because the threads are of little concern, but on non-damaged BB shells there are often "interference" issues. I've tried the EDCO Eccentric in a number of BB shells, and there have been only a few where it slides right in. Haven't yet really figured out what the mitigating factors are, but interestingly, one will slip right into the BB shell on an ALAN Record frame I have here in the shop.

There has been little if any discussion here on another "fix" for damaged BB shells. Campagnolo made "oversized" BB cups for it's Record and similar BBs, in all threadings. For example, the English "OS" fixed cup is 1.390x24 TPI, vs. the normal 1.370x24 TPI. The "OS" cups used the same internal parts as the non-OS cups. However, I can't recall ever seeing "oversized" taps. VAR catalogs don't list them. Did Campy make them? Were the OS cups made to just be driven in to damaged BB shells? Was this, indeed, a fix for damaged BB shells, or was there some other purpose?

Wayne -- Wayne Bingham Velo Classique PO Box 2069 Purcellville, VA 20134 USA 540-338-8376 http://www.veloclassique.com

Damaged BB fixes: was Re: Stronglight Bearings Question To: classicrendezvous@bikelist.org

Thomas Adams wrote:
>> Dear List:
>> http://www.velo-orange.com/grcruthbobr.html
>> For BB's with damaged/off line threading, Velo Orange now makes a
>> "threadless" bottom bracket that looks to be designed to resuce
>> hese frames. It's called the Grand Cru threadless BB, and uses an
>> expanding sleeve that is pressed into the threads, damaged or not,
>> as the adjustable cup is tightened. This looks like the BB only
>> locks onto the left side threads, but it's a neat looking fix.
>> It's also supposed to be a fix for french or swiss frames where you
>> don't want to spring for a Phil BB and/or can't find an orignal set
>> of cups. $60.00, JIS taper, lengths from 103 to 127 mm. Presumably
>> no offset, so you may have to shim the fixed cup or accept the left
>> crank being a bit further outboard.
>> However I presume a grossly out of round BB shell would not be
>> solved by this unit, and I'd worry about damage to threads in a
>> sound BB that you just can't find cups for. Anyone from V-O care
>> to comment?

The VO threadless bottom bracket, like the earlier Edco "Grip" threadless bottom bracket (http://tinyurl.com/y8qfxck), appears to have aluminum cups which would be unlikely to mar a steel bottom bracket shell. Indeed, the soft aluminum allows any existing threads to "bite" into cup material and help hold it in place.

I suspect a grossly out of round shell would only be an issue if it rendered it impossible to pass the cartridge through the shell.

-- -John Thompson (john@os2.dhs.org) Appleton WI USA