Roy quoted ;
> As p 172 in "The Dancing Chain" says:
> "1958-61. The Huret Monobloc rear derailleur required a unique
> braze-on two-bolt mounting. Cyclo, Huret, and Simplex could never
> agree on a standard derailleur hanger."
>
This is one of these statements in The Dancing Chain that's slightly off the
mark. For what commercial reason would any of the gear manufacturers have
produced new derailleurs that could not be fitted in some way to the bulk of
the frames already on the road as well as to new builds ?. By the 1930's
there was an accepted "Standard" mount, and that two bolt extension from the
from the frame end of the Jack Taylor was it !
At least until the late 1950's not only the gear manufacturers but the frame fittings folk like Nervex, supplied either "ends" as in the JT with this two bolt hole extension, or a "gear bracket" on it's own with the same two elongated holes, to braze on to the chainstay. There was an alternative clip-on version for the chainstay for frames not built with the facility. It has little to do with the method of operation, as it was used for gears moved by single cable, twin-cable, with a spring, without a spring, with a toggle chain et al.
The bit beyond this bracket, that is missing as it was not required here, is the lower half of the bracket,which was the "non-standard" "unique to the derailleur" part that was fitted between the bracket and the derailleur body itself. Manufacturers had no need to "standardise" this part.
Parallelogram style derailleurs that required the main attachment point / pivot to be nearer the axle centre (rather than in the case of Cyclo almost 2.7/16" in front of it) seems to have put paid to this style of mounting, hence perhaps it's demise.
I'd guess either that clip on the JT, was the Bros. using up old stock or that frame is considerably older....
Bob Reid Stonehaven Scotland
p.s Can anyone (Hilary ?) tell me the link to the comments about the accuracy of "The Dancing Chain" that were produced a few years back ?