Lewis is a difficult brand to understand. The derailleurs are relatively common for a minor brand of the 1930s or 1940s. But catalogues, adverts, reviews in magazines etc. are extremely rare. So people make up plausible stories for the brand - which may or may not be true.

Here is my version of the story of the Lewis touring models - which I think may be called 'Le Lewis Route'. Treat my story with a great deal of caution.

First off, these derailleurs share a number of key features:

• They are twin pulley devices with the guide pulley concentric with the p-pivot.
• The operating mechanism is a rod sliding in a cylinder.
• It is a direct-pull device with no toggle chains to break.
• A Bowden cable is fed up the inside of a sliding rod. The cable nipple is on the very inside, close to the spokes of the rear wheel. The cable exits the outer side of the cylinder and entering the outer cable. The cable is clamped at the lever.
• Lewis derailleurs are generally well made and decently finished, at least for aluminium products of the time.

I believe that these derailleurs were manufactured between about 1936 and, perhaps, 1948. The war years may account for some of the lack of catalogues, adverts etc.. There were many versions, that may have been produced in a sequence something like the following:

• I think the story starts in 1936 with a pleasantly over-engineered model that ran the cable over a pulley wheel mounted in the cap at the outer end of the cylinder. This model has a toothed guide pulley with no chain pusher plates around it.
• Shortly afterwards, perhaps in 1938?, the pulley wheel at the outer end of the cylinder was replaced by simpler, cheaper, cap with a tunnel shape that covered a shaped washer with a radius to ease the cable around the 90 degree corner.
• Shortly after this, possibly around 1940?, the toothed guide pulley was replaced by a plain circular pulley and two chain pusher plates were added either side of it. This plate assembly covered an arc of about 120 degrees.
• Then, maybe in 1942?, the arc shaped pusher plate assembly was replaced by simpler, cheaper round plates.
• Finally, possibly some years later in 1948?, the cast aluminium tunnel shaped cap on the outside of the cylinder was replaced by a simpler, cheaper dome shaped cap.

Throughout this sequence there may have been options offered to have various, otherwise identical, parts in either steel or aluminium.

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This is an impressive, unused, example of what I have called the third (1940?) version of a Le Lewis Route. Some of its attributes are:

• It clamps to the chainstay.
• The main mounting arm is polished aluminium and holds the sliding cylinder mechanism in a circular clamp.
• The brackets for clamping onto the chainstay are steel and black.
• The pulley cage arm is polished aluminium.
• The chain guides around the guide pulley form a shaped arc and are made of plated steel.

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• Derailleur brands: Lewis
• Country: France
• Date of introduction: 1940?
• Date of this example: unknown
• Model no.: unknown
• Weight: 214g including mounting brackets
• Maximum cog: 26 teeth (this size of sprocket is pictured in my only set of instructions)
• Total capacity: unknown
• Pulley centre to centre: 78mm
• Index compatibility: friction
• Chain width: 3/32”
• Logic: low normal
• B pivot: none
• P pivot: sprung
• Materials: aluminium mounting arm, cylinder and pulley cage, steel chain guide and sliding rod

Ref. 1933