Hi Bob, I am not sure of the earliest date of manufacture, but I have an identical pair of these levers. I purchased them new in 1977 for a PRN10 Peugeot and moved them onto a PX10 this summer. They were on display at Allin's cycle shop in the UK and may have been in stock for a while before I purchased them. So, although this is not an accurate date of manufacture, it at least informs us that this variation existed at that time.
I have a later pair of retrofrictions and I did not notice the difference until I read your email!!
I hope that this helps.
All the best, Peter Rogers
Barrie, Ontario, Canada
> Here are three photos from a recent eBay auction (Item number:
> 310174417074). Excellent photos by eBay seller "driftwares" and
> for this reason perhaps deserving of the very high $129 final bid.
>
> http://i368.photobucket.com/
>
> http://i368.photobucket.com/
>
> http://i368.photobucket.com/
>
> These show a Simplex retro-friction shifter set with less commonly
> seen "feet" at the bottom edges of the lever arms. These were
> supports for slots which held the ends of the internal springs. Most
> models had slots cut into the upper sides of the lever arms, just above
> the mounting bolts, which serve the same purpose.
>
> Placing the slot at the bottom minimized the potential for moisture
> and dirt to fall into the spring chamber. Perhaps a nice idea, although
> not as graceful in overall appearance.
>
> Would this be the very earliest version? Can anyone give the correct
> production date for this particular variation?
>
> I would love to see any catalog images which show this minor feature.
> Perhaps Daniel Rebour observed these in an early trade show and
> presented them in "Le Cycle"? My earliest US catalog illustrations
> show the "final" version - although forged with the same lever arm
> design pattern.
>
> I believe the retro-friction levers were first introduced in 1973,
> although they were rarely if ever seen in the US for perhaps
> another 2 years.
>
>
> BOB HANSON, ALBUQUERQUE, NEW MEXICO, USA