[CR] Damaged BB fixes: was Re: Stronglight Bearings Question

(Example: Framebuilders:Norman Taylor)

Date: Tue, 15 Dec 2009 12:06:52 -0800
From: "Thomas Adams" <thomasthomasa@yahoo.com>
To: <classicrendezvous@bikelist.org>, John <torup@sbcglobal.net>
In-Reply-To: <A88EE37A-1A6F-49C1-B77C-78F749C1A349@sbcglobal.net>
Subject: [CR] Damaged BB fixes: was Re: Stronglight Bearings Question


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 these 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?

Tom Adams
Manhattan, KS USA


--- On Tue, 12/15/09, John wrote:


From: John <torup@sbcglobal.net> Subject: Re: [CR] Stronglight Bearings Question To: classicrendezvous@bikelist.org Date: Tuesday, December 15, 2009, 10:10 AM

John Hurley asked if bikes (frames) even left the factory without the threads tapped and follow up questions if there is a problem what does one do?

Plenty-

And many arrived less than perfect, frames and bikes alike.

Way back the shop I worked for sold Bob Jacksons in 1972 through 1975. Some were sound, some were dreadful. My own track bike was the latter.

I did not build the bike up originally, upon its first bottom bracket repack... The bearing tracks in both fixed and adjustable cup were oval and did not match the machining. Toss that bottom bracket. Bring in the Campagnolo tool kit recently purchased to deal with these frames. Tap then face, it took 1mm off one side and 1.5 mm off the other to get aligned faces. It was assembled with new and adjusted well, but with a washer under the fixed cup to retrieve the metal lost and help the chainline.

One particularly bad frame was kept aside, Bob Jackson made a visit in 1974 and he was shown the frame, he measured and admitted that the fellow who clamped the Bottom bracket shell in the vice was a bit aggressive. A bit?

That frame did sell eventually with a Phil Wood bottom bracket. Anything else at the time would have been short lived.

There are a few cartridge bottom brackets now around to help save compromised frames.

My view on any bike is test, don't guess. Vintage bottom brackets are not getting much cheaper over time.

John Jorgensen
today in Torrance Ca USA