Despite being about the right age to have experienced a Huret Allvit rear derailleur in my youth (they were standard equipment on Schwinn bicycles and were manufactured in the multi-millions by the mid-1960’s), I missed out on the now well-reported unpleasant experience. Due to my parents purchasing proclivities, I ended up with Sears’ (Puch) internally-geared bicycles, and then eventually a Shimano-equipped Volkscycle, that latter of which I put many miles on before figuring out that something better was out there.
I’ve been recently working on the restoration of a Robert Ducheron machine whose date of build has yet to be determined. The bike was equipped with components dating from the 1950’s to the late 1960’s or early 1970’s. It arrived with a fully matched group of Huret Allvit shifters and derailleurs. R. Ducheron bicycles come highly prized, he being one of several artisanal French builders from the golden era. So, if Allvit derailleurs were spec’d by Mr. Ducheron, it would indicate confidence in their performance and reliability.
I had started to disassemble the mechanism, while noting that the spring has two notched positions for controlling chain tension. I also noted that the pulleys have adjustable cone ball bearings, rather than bushings. Not something expected on a low-end product. I also recalled that I’ve set up a few Allvits on bikes I’ve sold over the years, and remember being surprised at how well these “low-end” derailleurs shifted.
The above drawing, from a 1962 copy of Le Cycle magazine, shows the Allvit in all its glory, and with no less than 4 chain tension settings on the pulley cage. You can also see that the parallelogram is positioned at the bottom of the arm, which means that it can match the height of the freewheel cogs to engage them without tons of chain gap.
But, here is another 1962 Rebour drawing from the same edition of Le Cycle showing 3 chain tension positions. It would appear that there were several configurations of the Allvit, even within the same model year.
And, here is a 1966 advertisement from Le Cycle magazine, with this version showing 4 chain tension options.
Here is the full page of Rebour’s drawings in the Le Cycle 1962 edition, with accompanying text. According to the narrative, at this point in history, the Allvit had been equipped on a number of racers and tandems, winning the Poly de Chanteloup on numerous occasions. If this derailleur is truly low-end, how could these results be possible?
And the answer is nuanced. As time went on, the derailleur was cheapened, a process typical of the economics leading up to the 1970’s bike boom. The steel arm, now covered, proved to be flimsy and easily bashed out of adjustment, and the pull required to move the parallelogram proved to be very high, causing cable failure.
So, with that in mind, I plan to continue my overhaul of the Allvit, aided by the above instructions, courtesy of disraeligears.co.uk, an English language version well worth having. I’m hoping that with plenty of lubrication and adjustment, I just might get performance worthy of the Poly de Chanteloup!