After developing a successful gasoline-powered two-stroke piston engine in 1873, Karl Benz focused on developing a motorized vehicle while his wife Bertha financed its development. The original cost of the vehicle in 1885 was $1,000 which is equivalent to $26,337 in 2015. The vehicle was awarded the German patent, number 37435, for which Karl Benz applied on January 29, 1886. The Benz Patent-Motorwagen was a three-wheeled automobile with a rear-mounted engine. The vehicle contained many new inventions. It was constructed of steel tubing with woodwork panels. The steel-spoked wheels and solid rubber tires were Benz's own design. Steering was by way of a toothed rack that pivoted the unsprung front wheel. Fully elliptic springs were used at the back along with a live axle and chain drive on both sides. A simple belt system served as a single-speed transmission, varying torque between an open disc and drive disc.