This fine catalogue marks one of the key points in derailleur history - the introduction of the Terrot Modèle H, a serious derailleur bike produced by a serious company in serious volumes. It was the first time the derailleur had moved out of the ‘craftman’s workshop’ and into the ‘production engineer’s factory’.
This catalogue is also packed with information, not least about the bewildering range of transmission options Terrot offered:
- The most prominent pages in this catalogue, Page 3 to Page 8, are concerned with Terrot’s 6 different variable gears systems for bicycles - clearly the jewels in their crown. The derailleur system fitted to the Terrot Modèle H is described, on Page 8, as a ‘sensational novelty’.
- The section from Page 16 to Page 19 is devoted to Terrot’s Rétro-Directe models. These use a double freewheel and looped chain set-up that gave one gear ratio when pedaling forward (directe) and a different (usually lower) gear ration when pedaling backwards (rétro). If the pedals were kept still the bicycle freewheeled. Terrot also offered this rig with their 2 speed hub gear - giving four ratios - two when pedaling forward and two when pedaling backwards.
- Page 20 and Page 21 feature the amazing Terrot Modèle H, with its 3 speed derailleur system. It is described as the ‘dream bicycle for cycle touring’. The Terrot Modèle H had a static chain tensioning arm and a set of rear sprockets that moved from side to side to change gear. It appears from the gear ratios shown that the system might have used something like a 14 - 28 tooth 3 speed sprocket cluster.
- Page 22 and Page 23 show the Terrot Modèle TCF. In its basic, 2 speed, configuration this had a chain, freewheel and chainwheel on each side of the bicycle, with different gear ratios on each side. A cable controlled clutch mechanism determined which ‘side’ was transferring power - and hence which gear ratio was in use. Added gear ratios could be incorporated by using a double chainwheel and double freewheel on one or both sides. Doing this on one side gave 3 gears in total, doing it on both sides gave a 4 speed system. If the sum of the sprocket sizes was the same for both transmission sets on a given side of the bike, the same length of chain could be used on both. The chain on a given side was swapped between chainwheels and sprocket sets on that side by hand. It sounds mad, but systems like this were the preferred choice of Paul de Vivie for much of his life.
- Page 26 and Page 27 describe Terrot’s Levocyclette system. At this point in its long history, this was a 5 speed lever drive system. It was, perhaps surprisingly, a commercial success.
- Page 38 shows the legendary Terrot chain - with the ‘teeth’ on the chain and the ‘rollers’ on the chainwheel and sprocket. By 1905, this marvel was reaching the end of its commercial life - but it had been Terrot’s signature product before the advent of variable gears.
- Page 48 shows a very early gear table - the earliest that I have in my collection.