The Bedford OB model is a bus or coach chassis that was introduced by Bedford in 1939. It was designed as a successor to the Bedford WTB. The OB has a wheelbase of 14 feet 6 inches (4.42 m), and is a semi-forward control model, designed to carry 26 to 29-passenger bodywork. It is fitted with a 27.34 horsepower petrol engine, and has a four-speed manual gearbox and fully floating rear axle.