This site delves into pedalling backwards on unique old bikes using
My partly recreated Hirondelle bike's gearing system
HISTORY LESSON ....Retro-Direct gears were first patented in 1869 by Barberon and Meunier: rediscovered in 1899 using a double chain setup whereby pedalling backwards drove you forwards in a low gear passing to a higher one instantly and automatically just by pedalling forwards gave a two speed bike. In 1903 Hirondelle patented a single chain idea where a single chain went around a free-wheel drive sprocket , over a idler, then back over another but larger free-wheel sprocket giving two speeds provided you pedalled backwards. Hirondelle won a gold medal at the Touring Club of France Trials in 1905 which was a test bed for bicycle design improvements through (1902 to 1949). Using two chainwheels gave a four speed bike a great improvement for those days.(1924 to 1938). Two conical pulleys on an arm rotated around the bottom bracket to make the chain shift from one chainwheel to the other. This system was used on later models only. Derived from Ron Shepherd's book The Dancing Chain by Van der Plas Publications.
MY COMMENTS....Pedalling backwards isn't as hard as you might imagine and seems reasonably easy as everybody who has ridden it has testified. Pedalling off the seat seems odd at first though. It's amazing how few people seem to realise that you are pedalling backwards or maybe they are reluctant to say anything to an odd ball cyclist. Why be normal? A few hints if you are to make up one of these bikes. I had to widen the chainstay to accommodate the new lower main chain line and add a pivot point for the idler arm and it's sprocket. Keep the idler forward as much as possible, to avoid to much chain twist. Both freewheels are secured to the hub and operating in the normal fashion. I have used a bottom bracket bearing cup, half screwed into the older type freewheel, then screwed the newer one on, then screwed the lot to the hub. Use the front derailleur to change gear only when pedalling forward. An interesting thing is that you cannot roll this bike backwards as with normal bikes because the two freewheels oppose each other. The gear ratios are 73,64,47,41 ..the 48-18 (73 inches) 42-18 (64 inches) are by pedalling forward the 48-28 (47 inches) 42-28 (41 inches) are by pedalling backwards. If you have any further information on retro direct gearing. Let me know The above photo is of me and bike set up as used on the Great Victorian 2001 Bike Ride. Velovision article.