Military motorcycles such as; the BMW R75, Indian 841, and Harley Davidson, are the reason why the phrase ‘necessity is the mother of invention’ exists.
Produced to serve the military, this range of motorcycles was built during the World War II era to serve the American and German armies. The BMW R75, also known as the BMW R75 with Sidecar, was built under the German military’s instructions. The Indian 841 and Harley Davidson XA, on the other hand, were made to fulfill the requirements of the American army.
These motorcycle modes ushered in a new frontier that led to military motorcycle productions by aiding the various sides in winning the war. This BMW R75 vs. Indian 841 vs. Harley Davidson XA piece will highlight these models’ multiple specifications and features. Moreover, we will dive into how they matched up against each other in the field to see how far they impacted the war.
BMW was a very successful company by the time World War II started. The company had immersed a lot of popularity due to its highly efficient machines by the 1930s. In 1938, the German army saw a need for a motorcycle with a sidecar, capable of carrying three soldiers amidst any battle. On top of that, the bike was meant to take a gross weight of 500 kilograms / 1, 102 pounds.
BMW R75 design
The BMW design team responded to the German army’s request by making the BMW R75 with a sidecar. The motorcycle was built specifically for the military, and non like it were ever made for commercial purposes. It was only after the end of the war that some of these bikes were civilianized.
The introduction of the sidecar design was the first implementation of the design in the military. It borrowed from Hugo Young’s designs, an American inventor who came up with the flexible connection sidecar.
An axle was used to connect the third wheel to the rear wheel of the motorcycle. This connection was made through a locking differential. They used a transfer case to make off-road and on-road gear ratios (four gears and reverse gear) selectable. The use of this transmission made it possible for this bike to be used in almost any terrain.
BMW R75 Engine
The BMW R75 was made to withstand any terrain and any weather. The company repurposed the BMW R71 engine for the R75 but later had to come up with a new engine to be specifically used in just the R75.
Standardization of parts was made a necessity because the German army wanted the R75 components to be interchangeable with the Zundapp KS 750. The Zundapp KS 750 was another sidecar motorcycle model requested by the German military. The two bikes ended up sharing so many components that 70% of their parts can be easily interchanged.
In 1944, the Eisenach factory, which was used to produce the R75, was damaged greatly by the Allied forces’ bomb attacks. The damages caused led to the stoppage of production, at which point only 18, 000 units had been made.
The Indian 841 was made due to a response of the American army to the German all-terrain sidecars. Its design is loosely based on the BMW R71 and R75. The American company modified the BMW designs by using a motor across the bike’s frame in a 90-degree V instead of a boxer flat-twin design. This modification led to the name ‘Indian 841’ where 8 stands for the new engine design and 41 stands for the year it was made, 1941.
Before the United States joined World War II, it made sure to prepare itself first since joining the war was becoming inevitable. The United States War Department commissioned Indian and Harley-Davidson to make several shaft-drive, side-valve, V-twin test motorcycles.
The department offered Indian $350, 000 to make 1, 000 of these bikes, and that is how the Indian 841 came to be. The Indian 841 was meant to be used for desert warfare to counterattack the Germans with their highly effective BMW and Zundapp machines.
It could be used as a solo motorcycle or with a sidecar by just disassembling the sidecar potion. They also used shaft drives that helped them maneuver in desert sands and muddy fields. Even though the Indian 841 and Harley-Davidson XA were good bikes for the military, they ended up going for the Jeep.
The estimated number of units produced between 1941-1943 is around 1,056.
Harley Davidson XA
The Harley-Davidson was built alongside the Indian 841 after the US army requested the two involved companies to make the bike for them. Like the Indian 841 was a test/experimental motorcycle that was never adopted for more extensive military use. For this reason, a lot of Harley superfans do not address the XA as a real Harley.
Harley Davidson’s design greatly resembled the BMW R71, which was made between 1938 and 194, and the R75 made in 1941. Harley Davidson decided to copy the BMW bikes because of the military’s requirements and because the boxer twin design used by BMW was better at cooling.
Harley Davidson was using a transversely-mounted V-twin engine instead of the boxer twin in its WLA design. Changing to the boxer design enabled them to run the engine cooler by approximately 56 degrees Celsius.
Even though the Harley Davidson XA engine was not fully implemented in the military, it was used in various projects. Other experiments utilized the engine to make other sidecar bikes, tank generators, snowmobiles, and a sample Servi-Car.
The production, which began in 1942, ended in 1943 with just 1,016 -1,090 units made.
Specification Table Comparison
|BMW R75 specs||Indian 841 specs||Harley DavidsonXA sepcs|
Horizontally opposed flat-twin cylinder engine, two valves per cylinder, OHV (Overhead valve)
|4-stroke, Transverse side-valve 90-degree V-twin engine||4-stroke,
|Engine Capacity:||750 cc||737 cc||738 cc|
|Bore and Stroke:||78 x 78 mm / 3.1 x 3.1 inches||73 x 89 mm / 2.87 x 3.50 inches||77.8 x 77.8 mm / 3.063 x 3.063 inches|
|Transmission||Four-speed w/reverse (3-speed w/ reverse for off-road purposes)||Four-speed, shaft drive, foot shift||Four-speed, shaft drive, foot shift|
|Fuel Capacity:||6.3 US gallons / 22.7 liters||5 US gallons / 18.93 liters||4.1 US gallons / 15.5 liters|
|Power:||26 horsepower / 19.3 kW at 4 000 rpm||25 horsepower / 18.64 kW at 4 600 rpm||23 horsepower / 17 kW at 4 600 rpm|
|Weight:||930 lb. / 420 kg||528 lbs. /240 kg||538 lbs. / 244.03 kg|
|Top Speed:||60 mph / 95 kph||70 mph / 113 kph||65 mph / 105 kph|
|Tires:||Front, rear and sidecar: 4.5 x 16 inches||Front and rear: 4.1 x 18 inches||Front and rear: 4 x 18 inches|
|Brakes:||Front and rear: 9.8 inches / 250 mm drum brakes.|
Sidecar: .3 inches / 250 mm hydraulic brake.
|Front and rear: Drum brakes||Front and rear: Drum brakes|
Main Differences of BMW R75 vs Indian 841 vs Harley Davidson XA
The main design difference between these three models is the inclusion of a permanent sidecar in the BMW R75. The ability to carry three soldiers made it more versatile and functional than the rest. The sidecar wheel was shaft-driven powered through the back hub of the motorcycle for easy maneuverability.
As much as both Indian 841 and the Harley XA borrowed from the BMW R71, they still differ in various design aspects. The 841’s engine differs from Harley’s by the use of 90-degree cylinders which are positioned perpendicularly. Harley, on the other hand, uses the commonplace parallel configuration.
The R75 incorporated the use of a twin gearbox setup. The setup gave an equivalent of high and low range. The conventional foot lever was used to shift the gears. A hand level was used to switch between off-road and road gearboxes giving the bike incredible off-road capabilities. Comprising the off-road gearboxes were 3 forward gears and one reverse gear. The road gearbox, on the other hand, came with one reverse and 4 forward gears.
A great feature in R75 that wasn’t in the other models was fitted heaters. The heaters transferred heat into the footwell and handlebars from the engine. The heat prevented a lot of German soldier deaths who have otherwise died from frostbites.
Indian’s 841 featured military fittings such as a front fork holster, for packing a Thompson submachine gun, which was sometimes substituted with a rifle holster. This model had its throttle mounted on the left handlebar and used a hydraulic girder fork for the front suspension and shock absorption.
The transmission used in the 841 was toe-operated downshifts and heel-operated upshifts done by the heel and toe shift pedal. Another excellent addition was two separate gas tanks that provided a total of 5 gallons of fuel. Although the 841 was unique, it borrowed various components from the Indian Sport Scout. One such similarity is the bore and stroke, which is 2.87inches x 3.50 inches on both.
The 841’s weight is lower than the rest at 528 lbs. while the BMW R75 tops the charts with a whopping weight of 930 lbs.
Harley Davidson XA was meant to compete against the R71, which had proven formidable in the North African deserts. The US army wanted the bike to be low maintenance, very durable, and use a shaft drive.
XA used an air colling system that allowed the cylinder’s location in the pathway of the airstream, thus, producing a 100 degrees cooler system than its predecessor, the Harley Davidson WLA. The cooling system enables the bike to reach a maximum speed of 65 mph and produce 23 horsepower.
This bike’s military functionality demanded the soldier ride the bike with his left hand on the throttle, hence the placement of a left-hand throttle. The right hand was to be free to use a sidearm or operate the clutch while shifting.
Another excellent addition to the XA was the thick skid plate that helped in avoiding crankcase damage. It also came with a heavy-duty rack at the rear that was able to carry 40 lb. equipment.
The BMW R75 engine was an OHV (Overhead valve) horizontally opposed flat-twin cylinder engine with two valves per cylinder. The engine capacity was rated at 750 cc and the bore and stroke dimensions are 78 mm by 78 mm, capable of producing an output of 26 horsepower at 4,000 rpm.
The engine was air-cooled, featured a compression ratio of 5.8:1, and had two carburetors. It used a shaft to transfer the power to the rear wheel, while another transverse shaft was used to transfer the horsepower to the sidecar wheel. This design provided a whole drive to the two wheels.
Indian 841 ,on the other hand, used a four-stroke, transverse side-valve 90-degree V-twin engine that produced 25 horsepower and a top speed of 70 mph. The 841 also featured a compression ratio of 5.1:1 that made it run on low-octan fuel. They also had crash bars that were used to protect the cylinders from any accidents.
The engine, which was mounted longitudinally on the bike’s frame, transferred the gearbox’s power to the rear wheel using a shaft drive.
Harley Davidson XA decided to go with a 738-cc capacity engine based on the BMW R71 with a 4-stroke, horizontally opposite-valve 2-cylinder. It produced a power of 23 horsepower and reached a top speed of 65 mph by utilizing the compression ratio of 5.7:1.
The original price for these motorcycles is hard to estimate or classify since they were built for military purposes. However, we can see how they compare to each other price-wise using current resell values.
BMW R75 used bikes range from $9,000 to $12,000; this is less than what you will get the Harley Davidson XA. The XA comes in at an estimated value of $19,000 – $25,000, while the Indian 841 is the most expensive at approximately $30,000 – $45,000.
The rarity of the Indian 841 has made it one of the most expensive vintage motorcycles. The Harley is reasonably available, and BMW motorcycles are everywhere if you know where to look.
Similarities between BMW R75 and Indian 841 and Harley Davidson XA
All of these models used a shaft drive to transfer the engine power to the wheels. Borrowing from the R71, there was a need to upgrade the drive since the shaft drive already functioned flawlessly.
They also utilized the same air-cooling system with minor variations. For example, the XA placed the cylinder in the airstream pathway to cool the system more efficiently.
Purchasing one of these today may only be a thing for the most avid superfans. Considering the top speeds of these bikes, adrenaline junky fans won’t be too happy to get them, especially at their prices. Then again, there is a huge number of collectors who wouldn’t mind owning such a rich piece of history.
The BMW R75 is suitable for those who want a classic military vehicle reminiscent of the Nazi regime. It is a bike design you don’t see anymore and can carry three people and luggage. However, since you won’t be riding this to the market, we recommend you opt-out unless you are an enthusiast.
The Indian 841 is the preferred choice for most classic bike lovers. It has the highest speed of the three, the fuel capacity and power are more significant than the XA, and most importantly, the design is not as outdated as that of the R75. The problem with purchasing the 841 is its scarcity and price.
Harley Davidson XA is suitable for anyone who wants a functional bike that is still good-looking, readily available, and won’t break the bank. It is the safest choice for you if you can’t decide between the three.
Regardless of the bike, these three motorcycles embody a classic piece of military history that should satisfy any vintage motorcycle lover.