This Huret Competition rear derailleur was equipped on the Mercier Meca Dural bicycle I have been restoring. When I removed the derailleur from the frame, I wondered whether it was original to the bike. And, I really didn’t like it – with it’s rigid connecting arm and weird large upper opening which is supposed to connect to the space above the frame’s vertical drop outs. Perhaps I am a Simplex snob.
This plunger/pull-chain derailleur is similar to the Simplex TDF and Simplex Juy derailleurs of this era. But there is an important difference: there is no upper pivot on the derailleur arm, so it cannot move under chain tension. During this era, Simplex offered this extra feature on its plunger/pull-chain derailleurs, and I have enjoyed restoring a number of fine Simplex derailleurs from the early 1950’s which work well out on the road. Instead, this Huret derailleur mounts with a rigid arm extending from the chainstay. But because this Mercier Meca Dural has vertical dropouts, is the derailleur in the correct position? The Daniel Rebour drawing shown above shows this derailleur mounted on a frame with semi-horizontal dropouts. The position of the upper pulley in Rebour’s drawing, allows for more chain wrap, as opposed to my project, with its vertical dropouts pushing the derailleur down, with less engagement of the freewheel cogs.
Even so, I decided to overhaul the derailleur and keep my misgivings at bay. The pulleys have ball bearings – a really nice feature – which I overhauled by removing the pulleys from the cage, and cleaning and lubricating them. Each pulley has a set of cones under which the ball bearings reside, which can be tightened or loosened. I decided to leave the cone adjustment as found, but I did note that one pulley’s cones were quite a bit looser than the other’s.
I also cleaned and lubricated the pull chain – removing it completely from the derailleur and, cleaning and greasing it, then re-threading it. The re-threading is a little challenging – it takes patience to get the threads to re-engage.
One of the challenges with these types of derailleurs is to get the pulley cage in the correct position. Simplex even offered a drawing in its owner’s manuals to help cyclists install these derailleurs correctly. Generally speaking, the derailleur should be installed so that the monikers appear upright and/or readable, as shown below:
I’m not enamored with this derailleur, but after researching its origins, I believe it may be original to the bike. Even so, I may decide to replace it with a nicer Simplex model from this same era. First, I’ll test this derailleur to see how it performs.