Isetta (1955–1962)

Italian Origins The Isetta was conceived not by BMW but by Milan-based Iso, a firm run by industrialist Renzo Rivolta that had made refrigerators and motorcycles. Iso's designers set out to bridge the gap between a motorcycle and a proper small car, marrying cheap two-wheeler mechanicals with the weather protection and relative practicality of a cabin. The result, launched in Italy in 1953, was a diminutive egg-shaped runabout with a novel front-opening door.

BMW Takes a Licence By the mid-1950s BMW was in serious financial trouble, caught between costly luxury cars that few could afford and a shattered post-war economy. The company needed a model that would sell in volume and be cheap to produce. It acquired a licence (and tooling) from Iso in 1955 and heavily re-engineered the car — notably substituting a four-stroke single-cylinder engine derived from its own R25 motorcycle for Iso's two-stroke unit, to the point that the parts were effectively not interchangeable.

The Front Door and the Engine The Isetta's signature feature is its single front door: the whole nose of the car hinges open, and the steering column and wheel swing outward with it so occupants can step directly in. Power came from an air-cooled single-cylinder engine of roughly 250cc (Isetta 250, ~12 hp) and later 297cc (Isetta 300, ~13 hp), driving the rear wheels. Sub-250cc displacement was significant because it allowed the car to be driven on a motorcycle licence in West Germany until 1956.

Saving BMW The gamble worked. More than 10,000 Isettas were sold in the first year, and total German production reached roughly 161,728 units by the time it ended in May 1962. The profits and cash flow it generated were instrumental in keeping BMW solvent through its darkest decade, buying time until the 700 and the 1500 'Neue Klasse' saloons restored the company's fortunes.

Three Wheels, Four Wheels and Export Standard cars had four wheels but a very narrow rear track; a three-wheel version, with a single rear wheel, was offered for export markets — particularly Britain, where it could exploit motorcycle-licence and tax rules and was assembled at Brighton. Licensees in several countries added tens of thousands more cars to the worldwide total.

Corrosion is the dominant concern — floor pan, chassis, wheel arches, battery box and body seams, often worse on UK winter-used cars. Mechanically the single-cylinder engine can overheat if the cooling fan or its belt fails; many engines have already been rebuilt, though refreshing them is relatively straightforward. Worn gear linkages and bushes cause imprecise shifting. Water ingress via door and windscreen seals is common. Safety is inherently limited: no seatbelts or crumple zones as standard.

Structural integrity is everything: inspect the floor pan and chassis, battery compartment, wheel wells/arches and body folds for corrosion, since repairs can exceed a driver-grade car's value. Confirm the front-door hinge, latches and windscreen seal work correctly and don't leak (specialist knowledge helps). Check that the single-cylinder engine runs without heavy knock, that the oil-pressure warning light works, and that the cooling fan belt is sound. Verify whether the car is a four-wheel or narrow-track three-wheel version and that it matches its paperwork; the more common, more usable 300 tends to be the sweet spot.

As of mid-2020s, the Isetta occupies a friendly, stable corner of the collector market rather than a speculative one. Hagerty data show Excellent (#2-condition) values easing from a January 2017 peak of about $44,500 to a median near $38,500, with good (#3) drivers roughly in the high-$20,000s to about $29,300 for later 300s. In the UK, running/driving cars are commonly around £10,000–£15,000 with nicely restored examples about £25,000–£35,000. Rare special-bodied cars sit far higher: examples from the Bruce Weiner Microcar Museum sale included a convertible at ~$89,700 and a police car at ~$86,000. The car's oddball charm, tiny footprint and strong social-media appeal underpin a broad, loyal following and resilient values.