07/03/2014
The BMW Isetta, affectionately known as the "bubble car," remains one of the most distinctive and charming vehicles ever produced. Its unique design and practical approach to urban mobility captured the hearts of many during the post-war era. Manufactured by BMW, this microcar was a response to the growing demand for affordable and economical transportation. Let's take a closer look at what made the Isetta such a memorable icon.
The Genesis of the Bubble Car
The Isetta's story actually begins not with BMW, but with the Italian firm Iso Autoveicoli. Founded by Renzo Rivolta, Iso was initially known for its refrigerators and scooters. In the early 1950s, Rivolta sought to create a small, affordable car for the masses. The result was the Iso Isetta, which debuted in 1953. Its distinctive front-opening door, a design necessitated by its compact size, was a key feature that would define its identity. Recognising the potential of this innovative design, BMW acquired a licence to produce the Isetta in Germany. The Bavarian manufacturer, still recovering from the effects of World War II, saw the Isetta as an ideal solution to provide economical transport for a populace eager to rebuild and move forward. BMW's engineers set about adapting the design, most notably by redesigning the powerplant.
BMW's Touch: The Engine and Performance
BMW manufactured the 1957 BMW Isetta, and their contribution significantly shaped its character. They redesigned the powerplant around a BMW one-cylinder, four-stroke, 247 cc motorcycle engine. This engine, derived from BMW's successful R25 motorcycle, generated a modest 10 kW (13 hp). This was ample power for the lightweight vehicle, allowing it to achieve a top speed of approximately 53 mph (85 km/h). The Isetta debuted in April 1955 with this single-cylinder, four-stroke, 247-cc motorcycle engine. The engine's efficiency and reliability, coupled with the Isetta's feather-light construction, made it an economical choice for daily commuting. Later versions also saw the introduction of a 300 cc engine, offering a slight increase in power and performance.
Design and Features: More Than Just a Bubble
The most striking feature of the BMW Isetta is undoubtedly its innovative design. The single large door at the front, which opened outwards, provided access to the surprisingly spacious interior for two occupants. The steering wheel and instrument panel were attached to the door, swinging out with it to allow easier entry and exit. Inside, the Isetta was basic but functional. It featured a bench seat, a steering wheel, pedals, and a gear lever. The dashboard typically housed a speedometer and a few essential controls. Despite its small size, the Isetta offered a surprisingly comfortable ride for its class, with its independent suspension absorbing road imperfections effectively. The overall aesthetic was a far cry from the larger, more traditional cars of the era. Its rounded shape, large windows, and exposed headlamps gave it a friendly and approachable appearance, earning it affectionate nicknames like "Motocoupé" and "rolling egg."
Technical Specifications and Variations
The BMW Isetta was produced in several variations, primarily differing in engine size and minor styling cues. The most common models were the Isetta 250 and the Isetta 300.
| Feature | BMW Isetta 250 (1955-1962) | BMW Isetta 300 (1956-1962) |
|---|---|---|
| Manufacturer | BMW | BMW |
| Engine | 247 cc, single-cylinder, 4-stroke | 298 cc, single-cylinder, 4-stroke |
| Power | 10 kW (13 hp) | 11 kW (15 hp) |
| Top Speed | 53 mph (85 km/h) | 53 mph (85 km/h) |
| Transmission | 4-speed manual | 4-speed manual |
| Length | 2.29 m (7 ft 6 in) | 2.29 m (7 ft 6 in) |
| Width | 1.37 m (4 ft 6 in) | 1.37 m (4 ft 6 in) |
| Height | 1.37 m (4 ft 6 in) | 1.37 m (4 ft 6 in) |
| Wheelbase | 1.50 m (4 ft 11 in) | 1.50 m (4 ft 11 in) |
| Weight | ~230 kg (507 lb) | ~230 kg (507 lb) |
Engine Case Compatibility and Parts
For owners and enthusiasts looking to maintain or restore their BMW Isetta, sourcing the correct parts is crucial. The engine case, in particular, is a vital component. The provided information indicates that the crankcase (SKU 1-0010 and 1-0011) with stud bolts is suitable for BMW Isetta Export 250 and 300 cc models. It's important to note that some cases, like SKU 1-0010, are specified as not suitable for standard engines, suggesting there might be specific variations or modifications. When looking for a crankcase, details such as cylinder base mount diameter are important. SKU 1-0011, for example, is described as cleaned, degreased, and glass bead blasted, with all bearing seats and threads professionally checked, making it an excellent option for a new engine rebuild. The note regarding housing code numbers (40 for 250cc, 41 or no number for 300cc) and the possibility of using a housing for both by replacing the bearing plate highlights the interchangeability and specific technical nuances of these parts. Other essential engine components like crankshafts, fuel filters, bearing bushes, plug screws, and shaft seals are also available, often derived from BMW's motorcycle program. The availability of both new and used parts, including overhauled engines, ensures that the legacy of the Isetta can be preserved.
The Isetta's Enduring Legacy
Although production of the BMW Isetta eventually ceased in 1962, its impact on automotive history is undeniable. It represented a unique solution to the transportation needs of a specific time and place. Its charming design, economical operation, and innovative engineering have cemented its status as a beloved classic. Today, BMW Isettas are highly sought after by collectors and enthusiasts. They are a testament to creative design and practical engineering, offering a glimpse into a fascinating chapter of automotive development. The simplicity and character of the Isetta continue to resonate, making it more than just a car, but a piece of automotive art.
Frequently Asked Questions
- Who manufactured the 1957 BMW Isetta?BMW manufactured the 1957 BMW Isetta. They adapted the design and fitted it with a BMW one-cylinder, four-stroke, 247 cc motorcycle engine.
- What was the top speed of the BMW Isetta?The BMW Isetta typically had a top speed of around 53 mph (85 km/h), powered by its 247-cc or 298-cc engine.
- What engine case fits BMW Isetta export 250 & 300 cc?Crankcases with stud bolts, such as those with SKU 1-0010 and 1-0011, are suitable for BMW Isetta Export 250 and 300 cc models. It's important to check specifications like cylinder base mount diameter and any model-specific notes.
- Where did the Isetta design originate?The original Isetta design was created by the Italian firm Iso Autoveicoli, with BMW later acquiring the licence to produce it in Germany.
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