The BMW Isetta 250 – Pioneer of the Microcar
When BMW launched the Isetta in April 1955, the company entered entirely new territory. The microcar with its distinctive front-opening door and 247cc single-cylinder engine was born in an era of economic recovery, when affordable mobility for the broad population was in high demand. By 1962, over 73,000 examples of the 250cc variants had been produced in two versions – Standard and Export. A remarkable success story for such an unconventional vehicle.
Engine and Electrical System
The heart of the BMW Isetta 250 is a fan-cooled four-stroke single-cylinder engine with 247cc displacement. With a bore and stroke of 68 mm each, it is a so-called square engine. The V-arranged overhead valves are controlled via a camshaft driven by a roller chain. Lubrication is by pressure circulation; the carburettor is a BING type.
| SpecificationValue | |
| Engine type | 4-stroke, 1 cylinder, fan-cooled |
| Displacement | 247 cc |
| Bore × Stroke | 68 × 68 mm |
| Compression ratio | 6.8 : 1 |
| Power output | 12 hp at 5,800 rpm |
| Piston speed | 13.2 m/s at 5,800 rpm |
| Camshaft drive | Roller chain |
| Fuel tank | 13 litres (incl. reserve) |
| Fuel consumption (factory) | 3.3 L/100 km at 57 km/h |
| Test consumption | 5.0–5.8 L/100 km |
Gearbox, Clutch and Drive
Power is transmitted via a single-plate dry clutch to a BMW 4-speed gearbox with one reverse gear. The rear axle is driven with a reduction of 2.31 : 1. In first gear, the Isetta 250 can handle gradients of up to 27 percent.
Chassis, Steering and Brakes
| SpecificationValue | |
| Front track width | 1,200 mm |
| Rear track width | 520 mm |
| Wheelbase | 1,500 mm |
| Turning circle | approx. 8 m |
| Steering ratio | 16 : 1 |
| Brakes | Hydraulic drum brakes |
| Brake drum Ø | 180 mm |
| Tyre size | 4.80-10, 5-ply |
Dimensions, Weights and Performance
| SpecificationStandardExport | ||
| Length | 2,850 mm | 2,355 mm |
| Width | 1,380 mm | 1,380 mm |
| Height | 1,340 mm | 1,340 mm |
| Kerb weight | 350 kg | 350 kg |
| Payload | 230 kg | 230 kg |
| Top speed | 85 km/h |
Spare Parts for the BMW Isetta 250
For the restoration and preservation of a BMW Isetta 250, original spare parts and high-quality reproductions are essential. At Oldtimerteile.net we carry an extensive range – from engine, gearbox and chassis to body panels, electrics and accessories. The technical drawings in our shop help you identify the right part at a glance.
