('Hirondelle' by the Manufacture Francaise d'armes et cyles St. Etienne ca 1925)
(c) 2004 m.s.gerritsen

Hirondelle headbadge Hirondelle

Occasionally we get an old bike in the workshop, and this four speed retrodirect from around 1925 is special enough to be shown here. This post-war quality bike has two forward gears and two in reverse! Not that the reverse gears result in driving backwards, as the crossed chain restored drive in the preferred direction. The front changer follows the trend in providing upshift if you pedal forward, and in allowing downshifts if you pedal back and doubles the gears provided by the two freewheels!

The frame is, as with more french bikes from this era, constructed in lugless gaswelded construction, and the finish was nickel plated, as you can see on chainwheel which was protected by lubricant.

retrodirect sideview Les vitesses

Here you can see how the driveline works. Pedal forward and the chain rotates the smallest freewheel in the normal manner. The chain then runs over the idler and back over the larger freewheel towards the chainwheel up front. As the large freewheel spins slower than the smaller one, the freewheelpawls will do their thing.

Pedal backwards and the situation is reversed and the crossed chain will drive the largest freewheel. The small freewheel will spin backwards 

retrodirect driveline Curvature

On this picture you can see the curved chainstay, necessary to clear the crossed chain

The rearbrake must have inspired later designs


There is also a front changer: this is the control lever

featherbed predecessor Clever cogs

And here are the mechanics. The arm rotates around the bracketshell and is provided with two conical protrusions which lift the chain from one chaiwheel and direct it to the next one. To change up you rotate the arm up while pedalling forward, to change down you reverse the procedure while pedalling backwards.

Cartridge bracketaxle
The cartridge bracketaxle is easily removed if you unscrew the lockring. The hole in the RH side of the housing corresponds with an oiler in the bracketshell. The flange on the left is part of the frontchanger. 
The bearingtracks of this 75 year old cup and conebearing still look a lot better than many current offering new!
The same can be said for the headset (not shown)
Yes, it is an early cassettehub with outboard bearing on the RH side. The cogs slide on the hexagonal hub-end and are secured with a lock-ring. Only here the freewheels form part of the cogs, necessary because two independent freewheels are needed for the different speeds 
The spokenipples have their own logo. The prestavalves gave me another surprise, as I hadn't seen valves with a lefthanded thread before!