Re: [CR] Stronglight cup sizes

(Example: Production Builders:Teledyne)

From: "David Snyder" <dddd@pacbell.net>
To: <classicrendezvous@bikelist.org>
References: <000901c9cdaf$592222b0$6d7ba8c0@dkbwin2k>
In-Reply-To: <000901c9cdaf$592222b0$6d7ba8c0@dkbwin2k>
Date: Tue, 5 May 2009 13:31:50 -0700
Subject: Re: [CR] Stronglight cup sizes


I have previously measured my Gitane TDF's fixed cup at just a hair under 38mm. That's 38mm minus normal clearances. With any six-point socket, a fraction of a mm out of 38mm won't affect your ability to apply full torque, these cup's rounded corners notwithstanding.

So, it sounds like the ultimate tool will be a common 1-1/2" six-point socket, unless you want to hold said socket solidly in place with an 8X1.25X50mm bolt threaded into the spindle end, in which case a pair of flats will have to be ground onto the square-drive end of the socket for your 18" adjustable wrench.

I've so far always used the 18" adjustable wrench alone, but agree a socket tool would be much better. With adjustable wrenches it is most important that any burrs are removed from the jaws, burrs which can contact the bb shell and prevent the wrench from making full contact with the entire, measly ~4mm width of the cup's flats. Holding the wrench jaws squarely against the end of the bb shell is, of course, also critical. Often I can hang my armpit over the top tube to help generate the needed pulling force to the end of the handle, while using other hand to hold wrench squarely against bb face. The longer wrench reduces any tendency for the wrench to twist off of the fixed cup, as the pulling force needn't be as high.

In the case that I cannot remove the fixed cup, it's tight enough(!) so I'll rebuild the bb from the adj cup side.

I'll list a few of the affordable tools I have learned not to do without:

--18" adjustable wrench (bb's, freewheels and as cheater bar or anvil) --6" digital caliper (used thousands of times now, for everything including chain wear guaging) --spoke tensiometer (different spoke guages sound very different) --duckbill plier (gripping things and front derailer-cage spreading) --bike cable/hsg cutter --Dremel setup (seldom used, but when it's needed, it's needed) --silicone spray, kinked cable wire and air pump (to flush/scrub out lined cable housings)

David Snyder
Auburn, CA usa


----- Original Message -----
From: David Bean



> Stronglight sizes are baffling. Why 23.35mm for crank extractor threads?
> Why 38.1mm (which is exactly 1 1/2"!) or 37.8mm for fixed cups? (And my
> caliper sez that the one on my Gitane is more like 36.8mm.) Why the heck
> didn't they specify even millimeter (or even half mm) instead of these
> oddball measurements?

>

> David Bean