From BMW Tech
The Isetta was one of the most successful Microcar (a very small compact vehicle usually containing enough room for 1-3 people) produced in the post-World War II years—a time when cheap, short-distance transportation was most needed. Although the design originated in Italy, it was built in a number of different countries, including Spain, Belgium, France, Brazil, Germany and UK. Because of its egg shape and bubble-like windows, it became known as a Bubble car—a name later given to other similar vehicles. Other countries had other nicknames: In Germany it was das rollende Ei ("rolling egg"), Sargwagen ("coffin car"; the name apparently came from the small (or rather nonexistent) distance between the passengers and oncoming traffic) or Knutschkugel ("snogging ball"). In France it was the yogurt pot. In Brazil it was the bola de futebol de fenemê (soccer ball of FNM [a truck]), and in Chile it is still called the "huevito" (little egg).
Iso Isetta (Italy)
The car’s origins were with the Italian firm of Iso Rivolta. In the early 1950s, the company was building Refrigerator, motor scooters and small three-wheeled trucks. Iso's owner, Renzo Rivolta, decided he would like to build a small car for mass consumption. By 1952 the engineers Ermenegildo Preti and Pierluigi Raggi had designed a small car that used the Scooter (motorcycle) engine and named it Isetta—an Italian diminutive meaning little ISO. It is said that the stylists had arrived at the design of the Isetta by taking two scooters, placing them close together, adding a refrigerator and shaping the result like a teardrop in the wind.
The Isetta caused a sensation when it was introduced to the motoring press in Turin in November 1953, it was unlike anything seen before. Small (only 7.5 feet (2.3 m) long by 4.5 feet (1.4 m) wide) and egg-shaped, with bubble type windows, the entire front end of the car hinged outwards to allow entry and in the event of a crash, the driver and passenger were to exit through the Canvas Sunroof. The Steering wheel and instrument panel swung out with the single door, as this made access to the single bench seat simpler. The seat provided reasonable comfort for two occupants, and perhaps a small child. Behind the seat was a large parcel shelf with a spare wheel located below. A heater was optional, and ventilation was provided by opening the fabric sunroof.
Power came from a 236 cc (14.4 in³) 9.5 hp (7.1 kW) two cylinder Two-stroke motorcycle engine. The engine was started by a combination generator-starter known as Dynastart. A manual gearbox provided four forward speeds and reverse. A chain drive connected the gearbox to a solid rear axle with a pair of closely-spaced 10-inch rear wheels. The first prototypes had one wheel at the rear but this made the car prone to roll-overs, so they placed two rear wheels 19 inches (480 mm) apart from each other. This narrow track eliminated the need for a differential. The front axle was a modified version of a Dubonnet independent front suspension. The Isetta took over 30 seconds to reach 30 mph (50 km/h) from rest. Top speed was only about 45 mph (75 km/h). The fuel tank held only 13 Litre (3.5 Gallon). However, the Isetta would get somewhere between 50 to 70 miles per gallon of gas depending on how it was driven.
Two models were offered - the little egg-shaped Turismo with narrow 50 cm rear track, and the Autocarro, a commercial version with full-width rear axle. The Autocarro was offered in several body styles, a flatbed pickup, enclosed truck, a tilt-bed, or even a fire engine. The Autocarro was an extremely popular type of vehicle in Italy, and numerous manufacturers produced some variant of the type. Iso had previously produced a motorcycle-type Isocarro. The Iso Autocarro was larger than most, with its four-wheel layout, conventional rear axle with differential and leaf springs, and a large tubular frame. It was good for a 500 kg (1102 lb) to 600 kg (1323 lb) load. The name Isetta Autocarro was also used.
In 1954, Iso entered several Isettas in the legendary Mille Miglia where they took the top three spots in the economy classification: over a distance of 1,000 miles (1,600 km) the drivers achieved an average speed of over 70 km/h (43 mph). In view of its maximum speed, which was just 15 km/h (9 mph) higher, this was an almost incredible figure. However, despite its initial success, the Isetta was beginning to slip in popularity at home. This was mainly due to renewed competition from FIAT with its Fiat 500 model.
Renzo Rivolta wanted to concentrate on his new Iso Rivolta sports car, and was extremely interested in doing licencing deals. Plants in Spain and Belgium were already assembling Isettas and Autocarros using Italian made Iso components. BMW began talking with Rivolta in mid-1954 and bought not just a licence but the complete Isetta body tooling as well. Rivolta didn't stop with licencing the Isetta to BMW. He negotiated similar deals with companies in France and Brazil.
After constructing some 1,000 units, production of the Italian built cars ceased in 1955, although Iso continued to build the Isetta in Spain until 1958. It is thought that some 4,000 Autocarros were built.
VELAM Isetta (France)
VELAM acquired a licence from Iso in 1954 to manufacture a car based on the Isetta. Since Iso had sold the body making equipment to BMW, VELAM developed their own body but used the original Iso engine. The VELAM body was rounder and more egg-like than Iso's Isetta and was known by the French as the ‘yogurt pot’. Instead of a chassis like the Italian and German versions, there was a sub-frame bolted to the body at the rear, which held the rear tires, engine, and transmission. The front suspension was bolted to the front of the body. The front door was opened by push button instead of a handle, and the speedometer was mounted in the center of the steering wheel.
VELAM started production of the car in 1955 at the old Talbot factory at Suresnes, France and the car was introduced at the 1955 Paris car show. All told, five versions of the car were built: the standard Isetta, a convertible version, a luxury version, a one-off "Sport" version, and a race car. Due to competition from the Renault Renault Dauphine, production ceased in 1958.
In 1955 Iso licenced the Isetta to Romi, a machine-tool manufacturer headquartered in the city of Santa Bárbara d'Oeste, in the State of São Paulo. The Isetta was chosen because it was considered an ideal vehicle for use in the cities by virtue of its size and economy. Released in September 5, 1956, it was the first car produced in Brazil.
Some 3,000 of the Romi-Isettas were manufactured between 1956 and 1961. They kept the Iso design and used Iso engines until 1958; in 1959 they switched to the BMW 300 cc engines. Large numbers were exported to Argentina.
BMW Isetta (Germany)
BMW made the Isetta its own. They redesigned the powerplant around a BMW one-cylinder, four-stroke, 247 cc motorcycle engine making 13 hp (10 kW). Although the major elements of the Italian design remained intact, BMW re-engineered much of the car, so much so that none of the parts between a BMW Isetta Moto Coupe and an Iso Isetta are interchangeable. The first BMW Isetta appeared in April, 1955.
In May 1962, two years after launching the conventionally modern looking BMW 700, BMW ceased production of Isettas. A total of 161,728 units had been built.
BMW Isetta 250
While it retained the "Bubble Window" styling, it differed from the Italian model in that its headlamps were fixed separately to the sides of the bodywork and it carried the BMW badge below the windscreen. The car was also redesigned to take a modified version of the 250 cc 4-stroke engine from the BMW R25/3 motorcycle and the front suspension was changed. The single-cylinder generated 12 hp (9 kW) at 5800 rpm. The crankcase and cylinder were made of Cast iron, the cylinder head of Aluminium. However, the head was rotated by 180 degrees compared with the motorcycle engine. The twin-bearing Crankshaft was also different in the Isetta power unit, being larger and featuring reinforced bearings. One of the reasons for this was the heavy Dynastart unit which combined the dynamo and self-starter. The fuel mixture was provided by a Bing sliding throttle side draft motorcycle Carburettor. In addition to further changes of detail, the BMW engineers enlarged the sump for installation in the car and cooled the engine by means of a radial fan and shrouded ducting.
The power train from the four-speed gearbox to the two rear wheels was also unusual: fixed to the gearbox output drive was something called a Hardy disc, which was a Cardan joint made of rubber. On the other side of it was a cardan shaft, and finally a second Hardy disc, which in turn was located at the entrance to a chain case. A duplex chain running in an oil bath led finally to a rigid shaft, at each end of which were the two rear wheels. Thanks to this elaborate power transfer, the engine-gearbox unit was both free of tension and well soundproofed in its linkage to the rear axle.
In Germany the Isetta could even be driven with a motorcycle licence. The top speed of the Isetta 250 was rated as 85 km/h (53 mph).
The first BMW Isetta rolled off the line in April 1955 and in the next eight months, some 10,000 of the "bubblecars" were produced.
BMW Isetta 300
In October 1956 the Isetta Moto Coupe DeLuxe (sliding-window Isetta) was introduced. The bubble windows were replaced by longer, sliding side windows. The engineers had enlarged the single cylinder to a 72 mm bore and 73 mm stroke, which gave a displacement of exactly 298 cc, and at the same time they raised the compression ratio from 6.8 to 7.0:1. In this way the engine now generated 13 hp (10 kW) at 5200 rpm, and the torque rose to 18.4 N·m at 4600 rpm. The maximum speed remained at 85 km/h (53 mph), yet there was a marked increase in flexibility, chiefly noticeable on gradients.
In addition to the quest for better performance, there was another reason for the change: it was then still possible to drive the 250 cc Isetta with the old Class IV driving licence. Quite a number of Isettas were lovingly maintained by their owners for years and even decades, precisely because they possessed no other licence. On the other hand, from 1956 onwards, first-time drivers had to pass the test for Class III if they wanted to drive a car. True, the Class IV licence continued to be issued, but it was only valid for small motorcycles.
A second, similar reason for fitting the larger engine was the prevailing tax regime. The 250 cc engine did not take full advantage of the tax class, which then went up to 300 cc.
The BMW 600 was intended as an enlarged Isetta three-wheeler with more power and a more conventional four-wheel configuration.
The front end of the 600 was virtually unchanged from the Isetta, but the 600's wheelbase was stretched to accommodate four seats. A conventional rear axle was added. BMW introduced the semi-trailing arm independent suspension on the 600. This suspension would be used on almost every new model for the next four decades. Because of extra size and weight, the 600 had a more powerful engine than the Isetta. The 600 had the 582 cc Straight-2 engine from the R67 motorcycle. Top speed was 64 mph (103 km/h).
In two years only 34,000 600s were produced, partly due to price competition with the entry-level VW Beetle. In the late 1950s consumers wanted cars that looked like cars, and they had lost interest in economy models. Sales of the 600 were, however, aided by the energy crisis of 1956–1957.
BMW Isetta (United Kingdom)
With space for two and their luggage, the Isetta was perfect for the United Kingdom urban and rural roads. The first motorway, the M1 motorway, did not open until 1959, and more conventional cars such as early models of the Morris Minor could barely top 60 mph (97 km/h).
At one point, the British national health service started providing these vehicles for wheelchair users so they could drive while in their wheelchairs. Although noble in intent and many of these cars were made available free, the project was not deemed successful and was terminated.
In 1957, Isetta of Great Britain began producing Isetta 300 models at their factory in the former Brighton railway works under licence from BMW. The factory had no access by road, with components being delivered by rail, and finished cars being shipped out the same way.
The British cars had right-hand drive with the door hinged from the right hand side of the car and the steering column moved across to the right as well. Right-hand drive meant that the driver AND the engine were on the same side, so a 60 lb (27 kg) counterweight was added to the left side to compensate. Dunlop Rubber tyres were used, and Lucas Automotive electrics replaced the German Hella (company) and Robert Bosch GmbH components, with a different headlamp housing being used. Girling brake components replaced the ATE brake parts.
The Isetta was not popular in the UK until a three-wheeled version was introduced, and although three-wheelers were more prone to rolling-over, there was a financial advantage: if the reverse gear was not installed, they could evade automobile legislation and taxation by being classed as three-wheeled motorcycles, and could be driven with a motorcycle licence. Isetta of Great Britain continued to produce four-wheeled Isettas, but only for export to Canada, New Zealand, and Australia.
In 1962, Isetta of Great Britain also stopped production of the little cars but continued to produce Isetta engines until 1964.
Isetta replica kits
The now defunct British firm Tri-Tech, under the model name "Zetta", sold a kit car or even an assembled complete BMW Isetta lookalike replica from modern parts, including Honda CN 250 cc single cylinder water cooled engines with automatic transmission (standard) or Kawasaki Heavy Industries 500 GPS twin cylinder water cooled motorcycle engines with optional manual transmission.
Some parts, new or used, were from "donor" vehicles. Front suspension and steering is from (General Motors) Bedford vehicles (later sold under the Vauxhall Motors name) "Bedford Rascal" or the original and almost identical Suzuki "Suzuki Supercarry" light duty van or pick-up trucks. Drum Brakes and wheels are from Morris Motor Company and the subsequent British Leyland Motor Corporation "Mini". Prices range from c. £2650 for the kit up to c. £9450 for a complete version.
It could be legally registered for use under British laws. Tri-Tech also supplied some body parts which can be used for running non-exact restorations of BMW Isettas.
New Isetta (2010 - )
|Also called||Fiat Topolino|
|Automobile layout||Rear-engine design / Rear-wheel drive|
A new version of the BMW Isetta is likely to be introduced in 2010 sharing a platform with the Fiat Topolino. The car is expected to achieve Convert/LoffAonDbSoffF. 
- List of microcars by country of origin
- ↑ "The 100mpg fuel busters!". autoexpress.co.uk. http://www.autoexpress.co.uk/news/autoexpressnews/225675/the_100mpg_fuel_busters.html. Retrieved on 2008-08-02.
- BMW World - Isetta Section
- Romi of Brazil - Former Romi-Isetta's manufacturer 
- Romi-Isetta history in Portuguese 
- Yahoo Group page for the Isetta Owners Club of Great Britain Ltd. 
- A BMW community offering tech support forums, a DIY (Do It Yourself) knowledge base, and other resources for BMW enthusiasts 
- BMW Isetta Scale Models 
- 1959 BMW Isetta / Hot Wheels WHATTADRAG [http://www.microcarmuseum.com/tour/whattadrag.htm
- Isetta Rebuild Services 
- Isetta reborn 
- Interactive panorama of the inside of an Isetta 
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