Imme R100

Imme R100

Imme R100 viewed from the left
Manufacturer	Riedel AG
Also called	Riedel R100 Riedel Imme
Production	1948-1950
Assembly	Immenstadt, West Germany
Successor	ZMG R175
Class	Standard
Engine	99 cc (6.0 cu in) piston-ported two-stroke single-cylinder engine
Bore / stroke	52 mm × 47 mm (2.0 in × 1.9 in)
Power	4.5 PS (3.3 kW; 4.4 hp) at 5,800 rpm
Ignition type	kick start
Transmission	Three forward speeds with no neutral position
Frame type	Tubular steel spine frame, with engine mounted on the swingarm
Suspension	Front: Single-sided girder fork with coil spring and friction damper Rear: Single-sided swingarm with coil spring and friction damper
Brakes	Drum brakes, front and rear
Tyres	2.50 x 19, front & rear

The Imme R100 was a lightweight motorcycle made by Riedel AG from 1948 to 1951. It is noted for its simple and innovative design with many advanced features. With low cost and technical innovation, the R100 sold well, but reliability problems and low profit margins resulted in warranty costs driving Riedel AG into bankruptcy.

The advanced specification of the Imme R100 caused it to be highly regarded. The R100 was one of the motorcycles included in "The Art of the Motorcycle" exhibition at the Solomon R. Guggenheim Museum in 1998 and is on permanent display at Barber Vintage Motorsports Museum.

Motorcycle engineer Norbert Riedel recognized the need for a simple and economical light motorcycle during Germany's recovery from the Second World War and began to design one. By the summer of 1947, a prototype frame had been built and tested. The spine frame was made from 40 mm steel tubing, as were the steering head, the single-sided front fork, and the single-sided swingarm. The wheels were interchangeable, and were mounted from the left on stub axles attached to the suspension on the right.

Riedel developed the engine at the same time. This was a piston-ported two-stroke single-cylinder engine of 99 cc (6.0 cu in) capacity. The engine was cast in light alloy around the cylinder liner, and had an integral cylinder head. The crankshaft was suspended on only one side. The power output of the engine was 4.5 PS (3.3 kW; 4.4 hp) at 5,800 rpm, which was considered a high output at the time. Contemporary engines of comparable size typically made about 2.5 PS (1.8 kW; 2.5 hp), and 4.5 PS was expected from 125 cc engines such as those used in the DKW RT 125 and the later Hoffmann Vespa.