Hans Renold

Chain drive

The chain drive is a mechanical transmission system using a roller chain and sprockets to move torque across distance. Hans Renold’s 1880 bush roller chain solved critical wear and slippage problems of earlier pin-and-link designs—and became the basis for all modern precision roller chains. It enables adjustable gear ratios and higher torque via duplex configurations. But it inherently produces speed variation (chordal effect) due to discrete link engagement. Its first commercial validation came in James Starley’s tricycles using his 1877 differential. It remains essential hardware—not legacy tech—where reliability, torque and spacing outweigh the need for constant velocity.