model. This was replaced the next year by a constant-mesh transmission with three speeds and a reverse gear. Chassis and suspension The Servi-Car was designed for the road conditions of the day, where surface roads might still be crude and unpaved. It had a rigid rear axle with a differential. The rear axle had a track of , similar to the track of most available cars. This was done so that the vehicle could use the same tracks that had been made by regular cars. A prototype of the Servi-Car with rear suspension had been tested and was found to be unstable. The production model had its axle mounted directly to the frame with no suspension at all. Until 1957, the front forks of the Servi-Car were the springer-type leading-link forks used on the R-series and W-series solo motorcycles. From 1958 on, the Servi-Car changed neck stem length and inner diameter to use Hydra-Glide front forks. Brakes As introduced, the Servi-Car had a drum brake on the front wheel and another drum brake inside the rear axle housing, decelerating both rear wheels. In 1937, the braking system was upgraded to have a drum brake on each wheel. A hydraulic rear brake system was introduced in 1951. The very last Servi-Cars, built late in their last model year, would have disc brakes on all three wheels. See also List of Harley-Davidson motorcycles List of motorized trikes List of motorcycles of the 1930s References Servi-Car Tricycle motorcycles Motorcycles introduced in the 1930s