The Overhill 'Massed Start' gear
Author Phil Easton
Despite
the name of this gear the catalogue
shows a non-massed start setup for the bicycle. Overhill also
made a two-speed auto changer that worked via back-pedalling.
Overhill gears are mentioned in the "Dancing Chain" by
Frank Berto, and there is also an illustration in the Japanese "The Data Book".The Massed Start gear is a single wire type fork/spring arm derailleur, with the spring arm being fabricated using approx. 3/16" diameter spring wire, and adjustable sprockets, the upper one having its' own separate
spring tensioner. Supposedly the use of spring wire made it next to impossible to damage the arm. As I recall we used to call this type of derailleur a grass cutter. The sprockets on the spring arm look very similar to those used on Cyclo Standard or Ace.
The
operating cable goes all the way to the
inside end of the fork arm and simply pulls against spring pressure,
and the whole mechanism looks vulnerable to weather and road
grit. The top tube lever is simply made by folding some
shaped aluminum sheet over to double the thickness.Fabrication as you can see has the air of a school metal shop project (or at least back when I went to school), and is somewhat similar to the materials and methods used to fabricate the Bantel "Manx" brake calipers. My understanding is that these gears were only made for a few years, and I have seen adverts in "Cycling" around 1950 mentioning price reduction. On the left is an advert from Cycling (Supplement) 11 August, 1948
I have been told that Overhill Engineering Co. Ltd., Holton Heath, Poole, Dorset, remained in business for many years after the production of bicycle gears ceased, and that at least in 2006 the building was still standing, although neglected, with the last occupant using it for a business importing "antiques" from Europe.
The V-CC has an Overhill Catalogue in their archives. The scan of the advert is from August 11, 1948 Cycling, and the pdf is a scan of the catalog is from V-CC archives via Ray Miller.
Although a very simple gear, setting it up was not straightforward since it only wanted to be a 2-speed and not the 3-speed that it was supposed to be, this despite following instructions and tweaking the few available adjustments. Being short of time and a bit of a bodger I got round this problem by installing a 5/32" x 5-speed freewheel with the small sprocket removed. Although still being limited to an 1/8" chain due to size of sprockets on the spring arm this set up works well, with the large sprocket serving as a spoke protector, and with the chain line being preserved. When I get time I will try to get it to work as originally intended with an 1/8" x 3-speed freewheel.
In use it functions better than say a similar vintage piano wire Huret that I have, but due to limited ratios would not be something I would want to use on a long ride, really more about having something different, which it certainly is, at least in my part of the world. The chain used here is a modern SRAM.
The bike is a 1948 Maclean, frame number KA79 with old D Maclean, Jackson Street transfers.
 Top tube mounted single-cable
gear lever
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 Detail shot of rear changer
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