Greetings, Alistair, and welcome to the list!
Maybe instead of OZ gears, you mean Constrictor Osgear Super Champion? They were French "Super Champion" mechs, produced by Oscar Egg in France, marketed in Britain by Constrictor ("The Dancing Chain" pg.121).
Tension take-up arm and jockey wheel beneath the bottom bracket, shifting fork below the chainstay.
Try searching for references on Osgear.
> I am a new member and joined when I brought my fathers 1946 Ernie Clements
> bike from Scotland to Canada to start restoring it. I need some information
> on the bike of that era. When my Dad spec'd it out ( we was a member of the
> BLRC) it had a 531 tube frame, alloy wheels with Harden hubs, and OZ 4
> speed gear system (French make), B17 saddle, GB brakes etc.
> It is still all in great condition except that in the 60's when I used it
> to ride to High School on I had it painted and changed the gears to a
> Simplex set (the system with plastic componentS) . I would like to find out
> what the original colours were in 1946 ( it started off as a sort of light
> metallic green), locate the decals that were used in that period and source
> a set of OZ gears. I have been unable to find any references to OZ gears
> although he tells me they are very similar to the English Cyclo Ace system.
> Any input is appreciated
> Alistair Johnston
> White Rock, BC