Tiny car saved BMW from bankruptcy

The Isetta set the bubble car trend in motion

Bill Vance | CanWest News Service

Strange little vehicles that became known as “bubble cars” came onto the European auto scene in the 1950s. They were created in response to high gasoline prices and the need for low-cost, weather-proof personal transportation. They would wear names such as Messerschmitt, Heinkel and Isetta. These tiny, usually-three-wheeled cars were powered by air-cooled engines. Although small and basic, they were at least a step up in comfort and convenience from a motorcycle and sidecar, which was all many people could afford for family transportation.

Bubble cars owe their start to an Italian refrigerator manufacturer named Renzo Rivolta who, in 1952, decided to branch out into the car business by making tiny, basic cars. Since his fridges carried the Iso brand name, he called his little machine the Isetta, literally “small Iso.”

The Isetta, introduced in 1953, set the whole bubble car trend in motion. The most striking feature of this egg-shaped, two-passenger vehicle was the driver’s method of entry and exit. Perhaps Rivolta was influenced by his refrigerators when he designed it because the entire front of the car, including the windshield, was a side-hinged door that swung out, bringing the universal-jointed steering column with it.

Occupants stepped aboard, turned around and sat down, and the driver pulled the steering wheel back to close the door. In the event of a frontal crash, passengers escaped through the mandatory sunroof. The 1,194-millimetre front track was normal for a small car of that era, but the mere 508 mm between the rear wheels was decidedly unusual. It did, however, eliminate the need for a differential — a chain transmitted the power from the engine to a large sprocket attached to the drive axle in the rear housing.

The Isetta was powered by a 236-cubic-centimetre, two-stroke, two-cylinder air-cooled engine mounted just ahead of the right rear wheel, the location chosen to counterbalance the driver’s weight. The four-speed transmission was shifted by a lever with an upside-down-H pattern, located to the left of the driver.

Rivolta built the Isetta until 1955, when he ceased production. He returned to car building in 1962 with vehicles at the other end of the spectrum — high- powered sports cars called Iso Rivoltas.

As Rivolta was abandoning car building, BMW, the German auto and motorcycle manufacturer, was undergoing financial difficulties. Its luxurious six- and eight-cylinder cars were beautiful machines, but they were expensive and weren’t selling well enough to generate profit. Motorcycle sales were also soft. Faced with possible bankruptcy, BMW decided to get into the affordable, bottom end of the car market. It bought the rights to Renzo Rivolta’s Isetta.

BMW replaced the Isetta’s two-stroke with a modified motorcycle engine, an air-cooled, 247-cc, 12-horsepower, single-cylinder four-stroke. A 295-cc, 13-hp engine would be added in 1956 for the export model the Isetta 300. BMW also fitted a more conventional trailing arm and coil-spring front suspension in place of the horizontal coils used by Rivolta.

The Isetta sold well enough that, in 1957, BMW expanded the line with a four-passenger version. Called the 600, it had a flat, 585-cc, 19.5-hp, two-cylinder motorcycle engine.

The 600 retained the front opening door and added a right rear side door for access to the surprisingly roomy back seat. Transmission shifting was through a conventional four-on-the-floor gear lever.

Isettas were also built under licence in France, Brazil and England. Total production between 1955 and 1962 was almost 162,000 in four versions: bubble window, sliding window and convertible, plus a rare pickup truck.

The performance of the Isetta was definitely not freeway friendly. When Road & Track magazine (2/’58) tested a 300, it recorded a top speed of approximately 80 kilometres an hour and a zero-to-64-km/h acceleration time of 20 seconds. Fuel economy was tremendous, however, being in the range of 3.9 to 3.1 litres per 100 km.

The Isetta engine was started by a combination generator-starter unit called a Dynastart.

Visibility was excellent, akin to a fishbowl, and this turned out to be an important feature because large potholes would easily swallow the Isetta’s tiny 10-inch wheels. Parking, of course, was a breeze — one simply nosed into the curb and stepped out onto the sidewalk.

Isetta drivers could not be shy or retiring because the car attracted attention everywhere they went. The most common inquiry was: “Is this really a BMW?” Many people apparently missed this short chapter in BMW history.

The two-passenger Isetta and the 600 helped pull BMW back from the brink of bankruptcy. It introduced a 700 model in 1960, a more conventional-looking car, although one still powered by a rear-mounted, air-cooled twin. BMW’s big break came in 1962 with the launching of the conventional 1500 sedan, forerunner of the very successful 2002 model.

clock Posted Thu Aug 3rd, 2006

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