The Simpson Chain or Simpson Lever Chain was an English-made bicycle chain invented by William Spears Simpson in 1895. The design of this chain departed radically from the standard roller bicycle chain. The chain was composed of linked triangles forming two "levels". The inner level was driven by the chainring and the outer level drove the rear cog. Instead of teeth, the chainring and cog had grooves into which the rollers of the chain engaged.
Mr. Simpson made, widely discredited, claims that the levers of this chain provided a mechanical advantage that could amplify the energy produced by the cyclist. Racing teams were sponsored amid much fanfare as Mr. Simpson hired top cyclists (such as Constant Huret, who is depicted in Lautrec's famous advertisement, and Tom Linton of Paris-Bordeaux fame) and the Gladiator Pacing Team from France to race for high stakes in England for the Chain Matches. His teams were largely successful.
This invention would probably have been long forgotten except that
- The Simpson Chain is portrayed in a famous work of the French art nouveau artist Henri de Toulouse-Lautrec, and
- the Simpson Lever Chain Racing Team employed the Belgian cyclist Helene Dutrieu who later became the first woman licensed to fly an airplane in Europe.
- Mr. Simpson's promotions were so wide spread and effective that much of his promotional material is collected today
Known in the French language as la ChaÎne a Levier Simpson.