75 years of the BMW roadster

The style has changed, but not the content: “Many German motorists see motoring not just as a comfortable and fast means of transport, but also as a sporting activity. These are people who, once they see an aerodynamic car body with a long and sleek engine compartment, as well as a speedometer extending all the way to 150 km/h, feel that strong yearning for wide open roads simply perfect for driving fast, for Alpine passes just begging to be conquered, and for competitors so easy to overtake.” 

It was precisely with these words that BMW announced the company’s first self-engineered roadster in 1934. And indeed, this concept with its six-cylinder power unit was destined to shape the future of the brand, extending all the way to the current BMW Z4. 

The starting point for this development came at the Berlin Motor Show in May 1934. Here, together with the BMW 315 Saloon, BMW for the first time presented the prototype of a Sports Roadster with exceptionally attractive lines. Right behind the long and sleek engine compartment there were two sports seats tailored to the driver and front passenger protected by the low, raked windscreen and an emergency roof.

Left, world premier of the 315/1 BMW roadster at the Berlin Motor Show in May 1934
Below, a 1934/35 roadster, side view


 The rear end tapered out in an elegant sweep to the back of the car, adding a particular aerodynamic touch with excellent streamlining.

The radiator grille on this two-seater was inclined much further to the rear than on the Saloon, with mighty, sweeping front wheel arches extending on beneath the doors into the rear wheel arches. 

Both the saloon and the sports car were powered by the same outstanding engine: a 1.5-litre straight-six developed out of the 1.2-litre originally featured in the former BMW 303. While this power unit delivered maximum output of 34 hp on the saloon with its two carburetors, maximum output of the six-cylinder in the BMW 315/1 sports model was 40 hp. 

Front view of the BMW 315/1 

BMW 315/1 racing, circa 1934

 With the public simply falling in love with the BMW 315/1, BMW decided to build the car in a small series. Starting in summer 1934, BMW started a limited run of the 315/1 for public consumption. The production model differed from the prototype primarily through the modified arrangement of the headlights and side ventilation grids taking the place of the bent openings originally featured on the first model. 

Reaching a top speed of 120 km/h or 75 mph, the BMW 315/1 Roadster was one of the really serious contenders in the sports car market at its time. Indeed, BMW’s story of success on the race track quickly took on even greater significance with this new model, the BMW 315/1 achieving its first significant success in the International 1934 Alpine Rally. The BMW’s were the only cars in their class to complete the International Alpine Trophy without one single penalty point.

BMW soon started looking for more: a car in the prestigious category up to two litres. A more powerful version of the BMW Roadster – the 319/1 – entered the market in late 1934. Identical in its looks to the BMW 315/1 with the exception of the air vent on the engine compartment, the BMW 319/1 was powered by a 1.9-litre tuned to 55 hp and benefiting both from larger displacement and three larger downdraught carburetors with a top speed of 84 mph. 

In the mid-30s, production roadsters and competition cars were still very similar in technical terms – and motorsport was still the ideal place to prove the performance and reliability of a production car. But to keep up with the competition, BMW soon had to build cars with more power and muscle. So BMW’s engineers looked for ways and means to significantly increase engine output without increasing engine size. And they found the solution – the M328, the engine powering the legendary BMW 328 sports car in 1936.

Right from the start in its debut at Nürburgring on June 14, 1936, BMW’s new 
roadster literally pulverized even the most powerful supercharged competitors. This outstanding success was attributable to the well-balanced combination of superior engine power and cutting-edge suspension technology. Achieving 80 hp in the regular version and the low weight of just 1,830 lb gave this elegant roadster superior performance still impressive today. 

The famed BMW 328, which raced the Mille Miglia in 1938, left; 1940 BMW 328 piloted by
Waler Baumer who won the 1940 Mille Miglia

With the BMW 328 Roadster initially being restricted to motorsport as of mid-1936, production of the series model started in spring 1937. Over and above racing this high-performance car was very well suited for everyday use. And with its top speed of 96 mph, this was indeed one of the fastest cars on the road back then.

The BMW 328 Roadster remained a very rare bird, with only 464 units of this classic roadster being built up to 1940. 

While the 328 paved the way, the next two-seater sports car set new standards in design and elegance as of the mid-50s: the BMW 507. 

When making its debut in New York in 1955 the 507 left both journalists and the public absolutely spellbound. The long engine compartment, the cockpit tailored to the driver and passenger, the short and muscular rear end, stretched side lines and gently sweeping curves gave the car absolutely beautiful, timeless design.

At the same time the 507 came with a brand-new BMW face: The double kidney grille was now vertical instead of horizontal, sweeping elegantly between the headlights across the entire front end of the car. And the 507, at left below, also had a lot to offer within the engine compartment; an aluminum V8 acknowledged to this day as the first light-alloy V8 in the world built in series production. 

Finished in brilliant red, the sales brochure proudly presenting BMW’s new eight-cylinder sports car promised truly outstanding performance: 150 hp from 3.2 litres and top speed of 136 mph. And as an option BMW somewhat later also offered an upgraded version, delivering approximately 165 hp. This truly exclusive car went to exactly 251 proud owners between 1956 and 1959. 

With the roadster coming under increasing criticism in the ’60s and ’70s in terms of both safety and comfort, it took 29 years before the next roadster bearing the white-and-blue logo entered the market. This was the BMW Z1, at left, launched — ahead of its time in technical terms — in 1988.

The body of the Z1 was a steel monocoque made of pressed and welded metal 
panels and a plastic floor bonded into place. The entire outer skin was made up of plastic elements and panels likewise bolted on to the car, with the doors retracting on request into the high side-sills even while driving. 

The 170-horsepower 2.5-litre straight-six power unit and most of the car’s axle 
components came from the 3 Series. With the engine being fitted behind the front axle, the BMW Z1 was a front/mid-engine car, to use the technical term. Top speed was 140 mph and its zero to 60 timing was less than eight seconds.

The first units of the car built largely by hand were delivered to customers in January 1989. Production of the BMW Z1 finally ended in June 1991, after a production run of exactly 8,000 units.

The BMW Z1 was the breakthrough. More and more enthusiasts now showed 
growing interest in an open BMW two-seater – and in response BMW launched 
a roadster in 1995 built in large numbers for customers the world over. Very soon this compact performer became the epitome of BMW’s classic virtues, offering well-balanced technology within a truly attractive body and with a clear focus on driving pleasure. 

The BMW Z3, below, entered the market with a choice of two engines. Featuring a 1.8-litre four-cylinder two-valve power unit developing maximum output of 115 hp, the “regular” model accelerated to a top speed of 120 mph. The other option was a four-valve 1.9-litre four-cylinder delivering maximum output of 140 hp and a top speed 127 mph. 

With the Z3 proving to be a huge success, BMW was able in the course of time to offer a whole range of different engines meeting all kinds of different demands. Ultimately, therefore, the portfolio extended from the original 1.8-litre four-cylinder all the way to the 3.2-litre six-cylinder high-performance power unit carried over from the BMW M3, delivering up to 325 hp in the M Roadster and giving BMW’s compact sports car truly outstanding performance on the road. 

Entering the new millennium, BMW proudly presented a very special new model: the BMW Z8. With its sleek proportions, classic lines and soft folding roof, the Z8 was truly one of the most outstanding cars of its time through its looks alone. Measuring 173.2" in length, 72.0" in width, and 51.6" in height, this was indeed a modern interpretation of the former BMW 507.

Like its classic role model, BMW’s new roadster offered the very best technology available at the time in automobile production. Within the outer skin bolted on to the car, was a monocoque aluminum frame; spaceframe technology provided the load-bearing structure. 

The BMW Z8 featured a high-performance 5-litre V8 sports engine delivering no less than 400 hp combined with a manual six-speed gearbox.

The latest member of the BMW roadster family is the BMW Z4 presented for the first time at the Paris Motor Show in September 2002. From the start, this open two-seater not only marked a further highlight in BMW design language determined by the highly attractive interplay of convex and concave surfaces, hard edges and smooth, sweeping curves. 

The Z4 was available with a choice of two high-torque straight-six power units: the 231-hp Z4 3.0i or as the 192-hp Z4 2.5i. 

The modern interpretation of the classic roadster launched in spring 2009 with the new BMW Z4, combines more power with more style than ever before. It combines classic roadster proportions with the seating position moved far back close to the rear axle, rear-wheel drive and a fully automatic retractable hardtop. 

From Munich to Spartanburg, South Carolina, the history of BMW’s roadsters is a great lesson in automotive history.


The BMW Z4 manufactured in Spartanburg, S.C.

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