Re: [CR]Fixed cups, why assemble so tight??

(Example: Framebuilders:Alex Singer)

Date: Thu, 8 Dec 2005 12:30:47 -0800 (PST)
From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
Subject: Re: [CR]Fixed cups, why assemble so tight??
To: Neill Currie <neill_currie@comcast.net>, classicrendezvous@bikelist.org
In-Reply-To: <009501c5fc22$0cc7b770$6400a8c0@Presario>


Theoretically, French and Italian cups shown have to be well tightened, as (in theory) they should loosen in use. In fact, most of the most difficult-to-remove fixed cups I have encountered have been French, and therefore RH thread. So much for theory. The fact that French and Italian cups are still often very difficult to remove suggests that maybe the tendency of BB cups to work loose is greatly exaggerated and that lockrings on both sides could in fact usually be adequate. Ceratinly all sorts of sealed/cartridge BB's over the years have used lockrings or mounting rings on both sides, although some like Phil Wood reccomend use of Locktite on the rings.

Regards,

Jerry Moos Big Spring, TX

Neill Currie <neill_currie@comcast.net> wrote: So venerable list members, all this talk of loosening recalcitrant fixed cups has me thinking. I know that some fixed cups are tight, maybe even siezed in there. Anyway, I have at least 2 bb's that I have had in bikes in the past. One is a TA, the other has no name on it. Both of them use a screw in cup and mere lockrings on both sides of the BB shell for adjustment and tightness. Now, I would wager that a lockring can't be snugged as tight as a generic Campy fixed cup (as the ring squishes under the lockring tool through tightening).............so it begs the question: Do Fixed Cups have to be installed as tight as they seem to be installed, or do they function quite well with far less torque applied when installed? They are threaded left-handed, at least the English threaded are, and that would seem to be so they would tighten in use anyway. one wouldn't want them moving around in there, but if a mere lockring can do that.....

Neill "n-1 bikes=misery" Currie Hillsborough, Nh, USA.

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