Mitsubishi Buses

Large-Size Rear Engine Buses

Meeting Growing Passenger Demands

In 1951, Mitsubishi produced its first rear engine bus. The R1 had a capacity for 79 passengers and was noted as being the largest bus in Japan at the time. Mainly built on the B25 bonnet bus chassis, it was powered by a 110ps, DB series engine which had been adapted for rear engine mounting. Later in 1951, the 130ps, DB5A was adopted.
1952 saw the release of the R2 bus. Mitsubishi had gained a lot of experience with rear engine bus design through the development of the R1 and like the R1, the R2 incorporated the DB5A engine but utilized a much more efficient engine mounting technique. The R2 bus series comprised of four basic models -- the R21, R22, R23 and the R24 -- basing models on differences in size. In 1955, after 5 years of intensive development, the WR21 frameless bus, based on the R21 model was released.
Also in 1955, the R2 series underwent minor changes and was renamed the R200 series. Improvements were made to a number of components including the clutch to enhance driver operation, the chassis and springs to improve riding comfort, the steering to lighten steering operations and the adoption of the air-master brakes to upgrade stopping operations. The 130ps, DB7A with improved engine cooling was adopted.

In 1958, the R300 series replaced the R200 series. The 155ps, DB31 engine was incorporated resulting in a markedly improved acceleration and top end speed. Much more durable then its predecessor, it offered increased passenger capacity as well as improved riding comfort. A short wheelbase model as well as WR monocoque models were also introduced to appeal to as wide a user base as possible. Production of this series continued until 1960.

In 1955 and 1956, a total of 600 R32 buses were exported to Chile, Mitsubishi largest export market at the time. The R32 was specially developed for the Chilean market due to differences in regulations regarding size and weight, as well as in addition to the climatic differences.

Building on one strength to another, in 1959, the R400 series was launched featuring the 185ps, DB34 diesel engine, and Japan's first turbocharged bus was born. Power steering, air brakes, etc., combined with air suspension (first application of its kind) ensured upgraded riding comfort and ease-of-operations. The R40 series also had the longest wheelbase at the time in Japan. The popular series continued to incorporate the latest technological breakthroughs and in 1967, underwent a major model change.