BMW corporation (Bayerische Motoren Werke AG) introduced the first motorcycle under its name, the R32 with a flat-twin engine, in 1923. Motorcycle manufacturing now operates under the BMW Motorrad brand. "Motorrad" is German for "Motorcycle."
A flat engine is an internal combustion motor with multiple pistons that move in a horizontal plane. Typically, the layout has cylinders arranged in two banks on either side of a single crankshaft and is sometimes known as the boxer, or horizontally opposed engine. The concept was patented in 1896 by engineer Karl Benz (of Daimler-Benz and Mercedes-Benz fame), who called it the "contra engine."
This design was also popular in many German automobiles including Volkswagen. Other notable uses were in the Chevrolet Corvair, the French Citroën, and Subaru offers a boxer turbodiesel. The Toyota Sports 800 was Toyota's first sports car and contained a two-cylinder Boxer engine, the 2U. Although many of these implementations are air cooled, there are also water-cooled examples including the flat-six engines in the Porsche Boxster, Cayman, and later 911 models. Honda's top-of-the-line Goldwing motorcycle is a boxer engine design, also water cooled.
Boxer engines got their name because each pair of pistons moves simultaneously in and out rather than alternately, like boxers clashing their gloved fists together before a fight. Boxer engines have proved to be highly successful with up to twelve cylinders in automobiles and up to six cylinders in motorcycles, and they continue to be popular for light aircraft engines.
In the last decade, BMW Motorrad produced around 100,000 motorcycles annually. In May 2011, the 2,000,000th motorcycle produced by BMW Motorrad was a R1200GS, their current best selling model. It appears that, after the invasion of the US by Japanese motorcycles led to the downfall and collapse of many other brands, that BMW has found a stable and profitable market in the modern world. My unscientific count of bikes on the road, after eliminating Harley's and Japanese iron, I find BMW the most common bike encountered.
The end of World War II found BMW in ruins. Its plant outside of Munich was destroyed by Allied bombing. The Eisenach facility, while badly damaged, was not totally destroyed, and tooling and machinery had been stored safely nearby. After the war, most of BMW's engineers were taken to the US or the Soviet Union to continue the work they had done on jet engines with BMW during the war. I've visited the modern Munich BMW factory. It is across the road from the 1972 Munich Olympics site.
The terms of Germany's surrender initially forbade BMW from manufacturing motorcycles. In 1947, when BMW received permission to restart motorcycle production from US authorities in Bavaria, BMW had to start from scratch. There were no plans, blueprints, or schematic drawings because they were all in Eisenach, part of the Soviet dominated Eastern Germany. Company engineers in Munich had to use surviving pre-war motorcycles to copy the bikes. The first post-war BMW motorcycle in Western Germany, a 250 cc R24, was produced in 1948. The R24 was reverse-engineered from the pre-war R23 with some improvements over the R23, and was the only postwar West German BMW without rear suspension. In 1949, BMW produced 9,200 units and by 1950 production surpassed 17,000 units.
As the 1950s progressed, motorcycle sales plummeted. In 1957, three of BMW's major German competitors went out of business. In 1954, BMW produced 30,000 motorcycles. By 1957, that number was less than 5,500. In 1955, BMW began introducing a new range of motorcycles with Earles forks and enclosed drive shafts. These were the 26 hp 500 cc R50, the 30 hp 600 cc R60, and the 35 hp sporting 600 cc R69.
On June 8, 1959, John Penton rode a BMW R69 from New York to Los Angeles in 53 hours and 11 minutes, slashing over 24 hours from the previous record of 77 hours and 53 minutes set by Earl Robinson on a 45 cubic inch (740 cc) Harley-Davidson. This established BMW as a quality touring bike and a worthy competitor to the large US motorcycle brand.
Although U.S. sales of BMW motorcycles were strong, BMW was in financial trouble. Through the combination of selling off its aircraft engine division and obtaining financing, BMW was able to survive. The turnaround was thanks in part to the increasing success of BMW's automotive division. Most of BMW's offerings were still designed to be used with sidecars. However, by the early ‘60s sidecars were no longer a consideration of most riders; people were interested in sportier motorcycles.
While stationed in Norfolk, VA, during my Navy times, I tried out a BMW with a Steib sidecar. I don't recall exactly; it was probably something like an R60. I have driven Harley trikes, so I was experienced with riding a bike with more than two wheels. However, it is an odd feeling to actually "steer" around corners rather than to "counter-steer" and let the body lean the bike. Riding a bike with a sidecar is a different kind of experience from a solo bike.
For the 1968 and 1969 model years only, BMW exported into the United States three "US" models. These were the R50US, the R60US, and the R69US. On these motorcycles, there were no sidecar lugs attached to the frame and the front forks were telescopic forks, which were later used worldwide on the slash-5 series of 1970 through 1973. Earles-fork models were sold simultaneously in the United States as buyers had their choice of front suspensions.
In 1970, BMW introduced an entirely revamped product line. The engines were a complete redesign. The roller and ball-bearings in the bottom end had been replaced by shell-type journal bearings similar to those used in modern car engines. The camshaft, which had been at the top of the engine, was placed under the crankshaft, giving better ground clearance under the cylinders while retaining the low centre of gravity of the flat-twin layout. The new engine had an electric starter, although the traditional gearbox-mounted kick starter was retained. The styling of the first models included chrome-plated side panels and a restyled tank. The /5 series was given a longer rear swingarm, resulting in a longer wheelbase. This improved the handling and allowed a larger battery to be installed.
It was during this period that BMW in the US fully established themselves as a quality leader, lacking the dripping oil, vibration, and chain maintenance of the British and US brands. The 1974 publication by Montana author Robert M Pirsig of Zen and the Art of Motorcycle Maintenance contrasted a Harley and a BMW on a cross country trip. The book described more than the difference between the two bikes, but also the difference between the riders with the BMW driver described as a very organized individual who knew exactly where in his skillfully packed motorcycle one could find a pair of diagonal cutters. These were required to cut a bit of fence wire to repair a part on the Harley.
Although the book is less about motorcycles and much more about epistemology, ethical emotivism, and the philosophy of science, I highly recommend it to readers with bikes and without, regardless of the "highfalutin" words I use to describe it.
In 1977, the product line moved on to the "/7" models. The R80/7 was added to the line. The R90 (898 cc) models, "/6" and R90S models were replaced by updated versions with a new 1,000 cc; engine, the R100/7, the R100S and the new super sport model the R100RS with a full fairing. This sleek model, designed through wind-tunnel testing, produced 70 hp and had a top speed of 124 mph. The R100RS had a shorter rear end ratio to overcome the higher wind resistance of the full fairing.
In 1978, the R100RT was introduced into the lineup for the 1979 model year, as BMW's first "full-dress" tourer. The RS and RT fairings were very similar in appearance; however, the RS fairing was essentially a lightweight streamlining/protective shell and windscreen with no other functions, while the RT shell was heavier and had two "glove box" lockable compartments, ventilation louvres and an adjustable windscreen. The RT fairing was widely used for police motorcycles, with radio equipment in the fairing compartments.
The next year the R60 was replaced with the 650 cc R65. BMW added a variant in 1982: the R65LS, a "sportier" model with a one-fourth fairing, double front disc brakes, stiffer suspension, and different carburetors that added 5 hp. In early 1983, BMW introduced a 987 cc, in-line four-cylinder, water-cooled fuel injected engine to the European market, the K100. The K series comes with a simplified and unique rear suspension, a single-sided swingarm. This rear suspension give all BMWs a distinctive appearance reminiscent to high performance motocross bikes. A close mounted rear fender protects the rider when the "tire to top fender" distance is high.
In 1985, BMW introduced a 750 cc three-cylinder version, this one smoothed with another first, a counterbalance shaft. In 1986, BMW introduced an electrically adjustable windshield on the K100LT. In 1988, BMW introduced Automatic Breaking Systems (ABS) on its motorcycles. ABS became standard on all BMW K models. In 1993 ABS was first introduced on BMW's boxer (horizontally opposed cylinders) line on the R1100RS. It has since become available as an option on the rest of BMW's motorcycle range. In 1989, BMW introduced its version of a full-fairing sport bike, the K1. It was based upon the K100 engine, but now with four valves per cylinder. Output was near 100 hp.
As these examples and "firsts" demonstrate, BMW has always been an engineering driven company and did many things differently than most the competition. Known for their shaft drive rather than the much messier and adjustment requiring chain drive, many modern road bikes such as the Honda Goldwing have copied that basic design point. There are a few other bikes well known for shaft drive, such as the Moto Guzzi, but I think first of BMW any time shaft drive is mentioned. The lack of chain continues inside of the BMW engine with no secondary chain, but direct gear drive.
Going back to 1935, BMW fitted the first mass-produced hydraulically damped telescopic fork to their motorcycles. BMW still uses telescopic forks today on its F-series, G-series and HP motorcycles. But other front suspensions have also been a trademark of BMW. The R-series and K-series use the Telelever and the Duolever front suspensions.
Englishman Ernest Earles designed a unique triangulated fork that, unlike telescopic forks, resists the side-forces introduced by sidecars. BMW fitted the Earles fork to all its models for 14 years from 1955. Coincidently, 1955 was the year that use of sidecars peaked and quickly fell off in most European markets, but the Earles fork system was well liked by solo riders too. It causes the front end of the motorcycle to rise under braking — the reverse of the action of a telescopic fork. The mechanical strength of this design sometimes proved to be a weakness to the rest of the motorcycle, since it transfers impact pressure to the frame where damage is more difficult and expensive to correct.
The Telelever system was developed by Saxon-Motodd in Britain in the early 1980s. The Telelever is a unique front fork, where the shock absorber is located between and behind the two primary tubes attached to a telelever arm.
This system both lowers unsprung weight as well as decouples wheel placement function of the forks from the shock absorption function — eliminating brake dive and providing superior traction during hard-braking situations. This system improves comfort and stability considerably while providing excellent and sporty handling.
In 1930 BMW set the international speed record at 137.58 mph on a supercharged WR750 with a 735 cc engine. They improved on the record in ’32, ’34, ’35, and ’36 with the final at a speed just short of 169 mph on a 500cc bike. In 1937 they upped the record to 173.68 mph, again with a 500cc motorcycle. This was the final speed competition before the start of the Second World War.
In 2004, BMW announced the K1200S, incorporating a new front suspension based upon a design by Norman Hossack. BMW recognized this fact but paid Hossack no royalties. BMW named its new front suspension the Duolever. As of 2009, the Duolever is on the K1300S, K1300R and K1300GT.
The BMW K1200S with a top speed of 174 mph is considered the eighth fastest motorcycle in current production. It’s using 16 valves with 4 cylinders. The engine is DOHC, horizontal in-line, and liquid cooled. You can expect this motorcycle to produce 165 horsepower @ 10250 RPM. The transmission used by this fast motorcycle is 6 speed manual transmission. So, if you see one on the German Autobahn, think deeply before challenging to a race.
Another innovation, single-side rear suspension, was developed to simplify changing the rear tire. The first BMW monolever suspensions appeared in 1980 on the then-new R80G/S range. It had a single universal joint immediately behind the engine/gear-box unit. This system was later included on updated versions of the K & R Series.
The BMW 1200GS is, in my opinion, one of the finest road/off-road (dual sports) bikes made; equally at home on pavement and dirt with the comfort and power to ride the Interstate, while still easy enough to handle around town. It is one of the BMW GS family of dual sport motorcycles, featuring a 1,170 cc, 2-cylinder boxer engine with 4-valves per cylinder.
The K1300S with an in-line four cylinder water cooled mill is one of the most stylish road bikes available with an attractive and dynamic faring. That is the bike shown in the picture at the top of this article. This bike turns heads when spotted on the open road. You do have to spot it with your eyes, however, because, like most all BMWs, they are nearly silent. Although the roar of motorcycle pipes are music to many people’s ears, the soft whisper of a BMW reduces fatigue on those 400-500 mile days. Yet the 1300 cc engine produces 175 hp, so you won’t have any problem passing every other vehicle on the road, but watch out for smokey.
Although many large road bikes now have the reliability and comfort of BMWs, and the Honda Goldwing and related Japanese products might be considered as doing the German engineering one better, BMW is still thought of a something between a Cadillac and a Rolls Royce. Maybe a better analogy would be that a BMW is the Mercedes Benz of motorcycles … or make that the “BMW” of motorcycles.