a scooter motorcycle rear wheel transmission chain mechanism assembly unit

transmission chain chains chained close closeup macro micro detailed detail details scooter scooters motorcycles motorcycle brakes braking clamps clamp disc discs grip gripping stop stopping friction frictional force hold holding safety slow slowing regulate regulation speed speeds speeding vehicle vehicles commute commuting transport transportation fluid hydraulic hydraulics handle handles control controls valve valves open opening closing wheel wheels front rear back hose hoses leak leakage leaking