[CR]Hetchins with the arse-about-face bottom bracket

(Example: Racing:Jean Robic)

Date: Thu, 27 Mar 2008 04:12:24 -0700 (PDT)
From: "Norris Lockley" <norris.lockley@yahoo.com>
To: classicrendezvous@bikelist.org
Subject: [CR]Hetchins with the arse-about-face bottom bracket

I have managed to keep up with the contris about this irregular Hetchins bracket, made all the more peculiar because the shells used by the company arrived at the workshop with the threads already cut, otherwise the reverse threading could have been a custom order from a cyclist who believed, as I am tempted to do from time to time, that it is better to have a clockwise thread at the drive-side - that is, of course until, like so many Italian brackets, the cups loosen themselves.

I have never experienced this problem with any English frame, but came across it regularly with certain models of upper-end Motobecanes in the early to mid 80s. The reverse threading was called SWISS pattern, and normally the threads were the French 35mm metric ones. However a handful or so did arrive with the reverse threads using BSA threads, but whether this was as a result of mistakes at the factory, I never managed to ascertain.

With the frames being upper-end models, they were usually built up to a customer's own spec, with one of the de rigueur brackets at that time being the FAG-manufactured NADAX sealed bearing unit imported by Ron Kitching.

I remember that we used to dismantle these units to reverse the axle and, in the case of the BSA -threaded ones to reverse the aluminium cartridge body in the bracket shell.. It is all some time time and many bracket shells ago, but I seem to recall that both Stronglight and MAVIC made unit brackets that relied on being screwed into the drive side of the bracket shell, and I have a vague recollection that we used to reassemble these models too, to adapt to the oddly reverse threaded Motobecane shells.

However, as has already been advised the later MAVIC unit with the chamfered locking rings that did not rely on the bracket threads appears to be the way out of th problem with this Hetchins...but the solution still does not explain how the bracket came to be oddly threaded in the first place.

Norris Lockley, Settle UK

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