75 years of the BMW Roadster. The BMW 315/1 and its Successors.

Munich. 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
ompetitors 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
mergency roof. 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.
To reduce air drag to a minimum, the rear wheels were fully covered,
while the body of the car itself rested on an electrically welded
steel-pipe double frame with three crosswise box elements. Front
suspension was made up of the upper track spring, wishbones further down
and hydraulic lever-type dampers. The rear wheels, in turn, were mounted
on a live axle incorporating semi-elliptic springs and hydraulic
lever-type dampers. Small but hot: six-cylinder power unit displacing
1.2 litres. 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. The crankcase and
cylinder block of this outstanding engine were made of one single
piece, the engine featured one camshaft beneath the block, with tappets
operating the vertical hanging valves aligned in series via rocker
arms. The intake and exhaust pipes, finally, were on the same side. A
feature quite unusual today is the different distances between the
individual cylinders, with the second and third and, respectively, the
fourth and fifth cylinders being further apart, the space in between
being used for the crankshaft and amshaft bearings. The crankshaft
without any counterweights therefore ran in four bearings, just like
the camshaft. This was however not the reason for this particular
design and configuration, which was rather attributable to the assembly
process at the time, with the crankshaft being completely pre-assembled
together with the connecting rods and pistons. And since the pistons,
as a result, had to be inserted from beneath, the main bearings for the
crankshaft had to remain outside of the cylinders, not extending into
their contour lines. As a result, the main bearings had to be
accommodated between cylinders spaced out at a large distance. While
this power unit delivered maximum output of 34 hp on the saloon with its
two carburettors, maximum output of the six-cylinder in the BMW 315/1
sports model was 40 hp. And the standard of efficiency offered was
quite exceptional, BMW's engineers proudly stating that "this
beautiful and fast sports car consumes only 10-2 litres of fuel on 100
km, with oil consumption between 0.1 and 0.2 kg. So in terms of running
costs, it is no more expensive than a small car far lower down in the
market". With the public simply falling in love with the BMW
315/1, BMW decided to build the car in a small series - also because
the Company wanted to make a more powerful entry into the prestigious
world of motorsport. Starting in summer 1934, therefore, the very
attractive BMW 315/1 was retailed at a substantial 5,200.- reichsmarks.
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. Outstanding success in motorsport. 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 starter grid for
this rally in Nice was made up of 127 truly outstanding cars looking at
daily race sections of 500-600 kilometres to be covered at a minimum
speed. On the fourth day there was an additional speed test at Stilfser
Joch. After covering precisely 2,867 kilometres or 1,778 miles, 96 of
the 127 cars which had originally entered the race reached the finish
line in Munich - 66 thereof without having lost one point. The five
cars entered by the BMW Works Team were the only cars in their class to
complete the International Alpine Trophy without one single penalty
point, the BMW 315/1 Team Richard Brenner/Albert Kandl/Ernst v. Delius
finishing first in their category. Only 230 units of the BMW 315/1
were completed by mid-1935, many of them going to private drivers. One
of them was Ralph Roese, a BMW works driver for many years, who built
himself a BMW 315/1 Special. This was a complete re-build of the 315/1,
the highly modified engine ultimately developing no less than 136 hp in
a brand-new race car body weighing just 380 kg or 838 lb. Given
qualities of this kind, it is no surprise that this racing car finished
first in its very first race at Nürburgring in 1936, a staggering
17 kilometres ahead of the competition. Understandably, this special
model remained a great success over the years until finally winning the
German Road Racing Championship in 1939. Achieving this kind of
success, both the drivers and the Company soon started looking for
more: a car in the prestigious category up to two litres. And so it is
no surprise that another, even 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 carburettors. Obviously, an engine like this was easily
able to cope with a two-seater weighing just 780 kg, accelerating the
roadster in standard trim to a top speed of pproximately 135 km/h or 84
mph. At the same time this was of course a truly exclusive car due to
its retail price of 5,800 reichsmarks. Production from 1934-1936
therefore amounted to just 178 units, with the BMW 319/1 again bringing
home outstanding success in motorsport. The climax of the pre-war
era: the BMW 328 Roadster. 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 14 June 1936,
BMW's new roadster literally pulverised 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 characteristic of BMW roadsters to this day: 80
hp in the regular version and low weight of just 830 kg or 1,830 lb
gave this elegant roadster superior performance still impressive today.
With the BMW 328 Roadster initially being restricted to motorsport as of
mid-1936, production of the series model started in spring 1937. And so
this high-performance sports car was driven not only by BMW's works
drivers, but also by private customers since, over and above racing, it
was very well suited for everyday use. And with its top speed of 155
km/h or 96 mph, this was indeed one of the fastest cars on the road
back then. But again, the BMW 328 Roadster remained a very rare bird,
with only 464 units of this classic roadster being built up to 1940.
Comfort and elegance for all times: the BMW 507. While the 328 paved
the way for BMW's sporting activities, the Company's 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 and
sleek engine compartment, the cockpit perfectly 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, but
nevertheless clear and impressive 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 also had
a lot to offer within the engine compartment, boasting an aluminium 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 220
km/h or 136 mph. And as an option BMW somewhat later also offered an
upgraded version, delivering approximately 165 hp maximum output.
This truly exclusive car went to exactly 251 proud owners between 1956
and 1959. And not all of them wanted to enjoy this beauty merely as a
café cruiser, racing driver and the "King of
Hill-Climbing" Hans Stuck using a modified 507 in mountain races
in Europe and winning a number of events in his eight-cylinder
roadster. A spearhead in technology built for the road: the BMW Z1.
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 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 with its 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 fi tted behind the front axle, the
BMW Z1 was a front mid-engined car, to use the technical term.
Acceleration from a standstill to 100 km/h came in less than eight
seconds and the car's top speed was 225 km/h or 140 mph. Through its
extremely harmonious combination of materials and technologies, the BMW
Z1, weighing just 1,250 kg or 2,756 lb, was a truly dynamic roadster
still thrilling today in terms of stiffness, its low centre of gravity,
and stability in bends. The first units of the car built largely by
hand were delivered to customers as of January 1989, the base price of
DM 80,000.- ensuring lasting exclusivity. Production of the BMW Z1
finally ended in June 1991, after a production run of exactly 8,000
units. Sheer driving pleasure in large numbers: the BMW Z3. 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 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 100 km/h in 10.5 seconds
and reached a top speed of 194 km/h or 120 mph. The other option was a
four-valve 1.9-litre four-cylinder delivering maximum output of 140 hp
for acceleration to 100 km/h in 9.5 seconds and a top speed of 205 km/h
or 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. A
fascinating milestone in automotive technology: the BMW Z8. 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 4.40 metres or 173.2" in length, 1.83
metres or 72.0" in width, and 1.31 metres or 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, a monocoque aluminium frame, that is
spaceframe technology, provided the load-bearing structure and gave the
driver and passenger an extremely direct feeling of the road and the
driving experience. Within its engine compartment the BMW Z8 featured
a high-performance five-litre V8 sports engine delivering no less than
400 hp. Combined with a manual six-speed gearbox, this supreme engine
enabled the driver to enjoy the utmost in performance at all times and
under all conditions. Indeed, this superiority translated into equally
clear facts and figures, the ambitious driver being able to lap the
20-km Nord-schleife of Nürburgring in the Z8 in a remarkable 8:15
minutes. An unmistakable athlete to this day: the BMW Z4. 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, but also set new standards in its class. The exciting design
of the car was determined by the highly attractive interplay of convex
and concave surfaces, hard edges and smooth, sweeping curves.
Available from the start with a choice of two high-torque straight-six
power units, the Z4 - either in the guise of the 231-hp Z4 3.0i or as
the 192-hp Z4 2.5i - guaranteed roadster motoring at its best. The
outstanding agility of the BMW Z4 is ensured by the car's wide track, an
extremely low centre of gravity, optimum 50:50 axle load distribution,
and the very precise electric power steering. Fading-free
high-performance brakes, runflat tyres featured as standard, and
Dynamic Stability Control (DSC III) with an add-on traction mode
finally, guaranteed supreme driving safety under all conditions.
Style and performance: the new BMW Z4. The modern interpretation of the
classic roadster launched in spring 2009, the new BMW Z4, combines more
power with more style than ever before. Indeed, this is the only car in
its segment to combine classic roadster proportions with the seating
position moved far back close to the rear axle, rear-wheel drive and a
fully automatic retractable hardtop. The new BMW Z4 offers all the
driving pleasure of a BMW roadster in particularly refined style.
Driving with the roof down, this outstanding two-seater provides a
refreshing experience of the sun shining in and the wind rushing by,
with the hardtop closed it ensures the same level of all-round comfort
as a sporting coupé in the premium segment. So through its wide
range of diverse qualities alone, the new BMW Z4 is indeed the re-birth
of the roadster. Here again, it is certainly appropriate to quote the
"BMW Blätter", the original BMW Leaflets in their
description of the BMW 315/1 back in 1934: "In a nutshell you can
describe BMW's new sports car as the fast, beautiful and reliable car
bound to give the ambitious sports driver one exhilarating experience
after the other, at the same time combining all the advantages of an
economical touring car."