Horses in warfare of today's English saddle. Both the Scythians and Assyrians used pads with added felt attached with a surcingle or girth around the horse's barrel for increased security and comfort. Xenophon mentioned the use of a padded cloth on cavalry mounts as early as the 4th century BC. The saddle with a solid framework, or "tree", provided a bearing surface to protect the horse from the weight of the rider, but was not widespread until the 2nd century AD. However, it made a critical difference, as horses could carry more weight when distributed across a solid saddle tree. A solid tree,
Timing belt (camshaft) overhead cam four-cylinder design which used a timing belt, a configuration which became one of the most common. A timing chain, also called a sync chain, is used on tandem bicycles, to synchronize crank movement between the captain (front rider) and stoker (rear rider). As with auto engines, proper tension of the timing chain is necessary to prevent premature wear of the drivetrain components. Tension is adjusted by means of an eccentric bottom bracket. Timing belt (camshaft) A timing belt, timing chain or cambelt is a part of an internal combustion engine that synchronizes the rotation of the crankshaft and