A motorized bicycle is a bicycle with a motor or engine and transmission used either to power the vehicle unassisted, or to assist with pedaling. Since it sometimes retains both pedals and a discrete connected drive for rider-powered propulsion, the motorized bicycle is in technical terms a true bicycle, albeit a power-assisted one. Typically they are incapable of speeds above ; however, in recent years larger motors have been built, allowing bikes to reach speeds of upwards of 113 km/h (70 mph).
Powered by a variety of engine types and designs, the motorized bicycle formed the prototype for what would later become the motor driven cycle.
Terminology The term motorized bicycle refers to just a bicycle combining pedal power and internal combustion engine power. However, the term could be used as an umbrella category to refer to bicycles using sources besides pedal power. Electric bicycles technically could be in the category of motorized bicycles but instead of using internal combustion engines as a combination it is driven by electric motors which power from pedals and batteries. Mopeds are also almost motorized bicycles since they function the same way as these vehicles but with engines less than .
The term motorized bicycle should not be confused with motorcycle since this type of vehicle uses a combination of pedal power and engine power whereas motorcycles are purely either internal combustion engine or electric motor powered.
Design and usage Motorized bicycles have utilized all variety of engines, from internal-combustion (IC) two-stroke and four-stroke gasoline engines to electric, diesel, or even steam propulsion. Most motorized bicycles are based or derived from standard general-purpose bicycle frame designs and technologies, although exceptions abound. In addition, modifications to a standard bicycle frame to support motorization may be extensive.
The earliest motorized bicycles were ordinary utility bicycles fitted with an add-on motor and transmission to assist normal pedal propulsion, and it is this form that principally distinguishes the motorized bicycle from a moped or motorcycle. In a day when gasoline engine and transmission designs were in their infancy, and power-to-weight ratios were low, a dual-purpose propulsion system seemed particularly advantageous. As time went on, pedal propulsion was increasingly replaced by constant use of a two or four-stroke gasoline engine. Nevertheless, the concept of using motor assist for the ordinary bicycle has persisted, and the concept has periodically resurfaced over the years, particularly in times of austerity or fuel shortages. In countries where automobiles and/or fuels are prohibitively expensive, the motorized bicycle has enjoyed continued popularity as a primary mode of transportation."China: Exhaustive Effort to Cut Vehicle Emissions", China Business Information Network, 10 April 1996. p. 1, via Financial Times Information Limited: In 1996, the city of Shanghai, China had 370,000 motorized bicycles and 470,000 other vehicles.
The design of the motorized bicycle varies widely according to intended use. Some motorized bicycles are powerful enough to be self-propelled, without use of the pedals. A development of the motorized bicycle is the moped, which commonly has only a vestigial pedal drive fitted primarily to satisfy legal requirements, and suitable only for starting the engine or for emergency use. The alternate design philosophy to the moped is the so-called motor-assist or pedal-assist bicycle. These machines utilize the pedals as the dominant form of propulsion, with the motor used only to give extra assistance when needed for hills or long journeys.
History
The two-wheeled pedal powered bicycle was first conceived in Paris in the 1860s. By 1888, John Dunlop's pneumatic tire and the chain drive made possible the safety bicycle, giving the bicycle its modern form.
The origins of the motorized bicycle or motorbike can be traced back to the latter part of the 19th century when experimenters began attaching steam engines to bicycles, tricycles, and quadracycles. The first true motorized bicycle is generally considered to be the French Michaux-Perreaux steam velocipede of 1868. The Michaux-Perreaux was followed by the American Roper steam velocipede of 1869, built by Sylvester H. Roper of Roxbury, Massachusetts. Roper demonstrated his machine at fairs and circuses in the eastern United States in 1867, and built a total of 10 examples. These early attempts at propelling a bicycle by means other than the human body were not successful, either practically or commercially. It was not until the 1890s, with the advent of the gasoline-powered internal combustion engine (ICE), that the motorized bicycle could be considered a practical machine."Horseless Carriages", The Times, 21 May 1896, p. 6, via The Times Digital Archive
One of the first gas motor-assisted bicycle designs was the Millet motorcycle developed by Félix Millet in France in 1892. Millet's designs had both pedals and a fixed-crankshaft radial engine built into the back wheel.
In 1896, E. R. Thomas of Buffalo, New York, began selling gasoline engine kits for propelling ordinary bicycles. After forming the Thomas Motor Company, he began selling complete motor-assisted bicycles under the name Auto-Bi. The Auto-Bi is generally considered to be the first production motorized bicycle made in the United States.Rafferty, Tod, The Complete Illustrated Encyclopedia of American Motorcycles, Philadelphia, PA: Courage Books, p. 16
The 1900 Singer Motor Wheel was a wheel incorporating a small ICE powerplant that could be substituted for the front wheel of a bicycle. A later design, the 1914 Smith Motor Wheel, was attached to the rear of a bicycle by means of an outrigger arm, a design later taken up by Briggs & Stratton.
In Belgium, the Minerva company, later known for luxury cars, started out manufacturing standard safety bicycles in 1897, before expanding into light cars and "motocyclettes" from 1900. They produced lightweight clip-on engines that mounted below the front down tube, specifically for Minerva bicycles, but also available in kit form suitable for almost any bicycle. The engine drove a belt turning a large gear wheel attached to the opposite side of the rear wheel as the chain. By 1901 the kit engine was a unit developing , comfortably cruising at at 1,500 rpm, capable of a top speed of , and achieving a fuel consumption in the range of . These kits were exported around the world to countries including the United Kingdom, France, Germany, the Netherlands, Australia, and other British territories of the time.
As engine power increased, frame ruptures became increasingly common, and by 1903 Minerva had developed an in-frame design with the engine mounted above the bottom bracket, while still also offering the clip-on kit. From 1904 Minerva began focusing more on car production, and while development and production of the Minerva motorized bicycles continued through to about 1909, they became a less and less significant part of the company.
In England, the Phelon & Rayner motorized bicycle was introduced in 1901, and was sold through 1903. The original Phelon & Rayner machine used a , gasoline engine mounted to a standard 28-inch bicycle frame.
In the United States, the California Motor Company was formed in 1901 to sell complete gasoline-engine motorbikes in San Francisco, Oakland, and San Jose.Rafferty, Tod, The Complete Illustrated Encyclopedia of American Motorcycles, Philadelphia, PA: Courage Books, p. 22 The company began with a 200 ccRafferty, p. 22: Other sources state that the Marks engine in the California was only 90 cc in displacement, but a 1901-vintage 90 cc low-compression four-cycle engine running the 30-octane gasoline of the day was unlikely to generate 1.5 horsepower and 25 mph on the California, which weighed some 75-80 pounds, not counting fuel, oil, and rider.Bill, L. H., The Poor Man's Automobile, Overland Monthly and Out West Magazine, Vol. 40, Issue No. 2 (August 1902), pp. 197-198 single-cylinder, 1.5-horsepower, four-stroke engine designed by R.C. Marks. Mounted to a standard bicycle frame, the California could reach speeds of approximately 25 mph (40 km/h).Rafferty, p. 22 The California weighed around 75-80 pounds, and featured a leading-link front fork, a leather spring saddle, a front Duck roller brake, and an Atherton rear coaster brake.Bill, pp. 197-198Wyman, George A., Across America On A Motor Bicycle, The Motorcycle, Issue 1, Volume 1, (June 1903), pp. 46, 48, 55Mitchell, Leon, 1903 California Specifications , Leon's Vintage Motorcycle Page, 1998-2002 A leathern belt-drive directly connected the engine output shaft to the rear wheel. During the summer of 1903, George A. Wyman rode a , California from San Francisco to New York City, becoming the first person to cross the North American continent aboard a motor vehicle.Rafferty, p. 22: Wyman's California was the very first motor vehicle to successfully cross the entire United States, making the journey in fifty-one days, from May 16, 1903 to July 6, 1903.
As early as 1903, motorized bicycles were being fitted with larger and heavier loop frames designed to specifically accommodate larger displacement engines, which produced higher speeds. These new motorbike frame designs soon incorporated a new riding position that no longer centered the rider over the pedals, but instead moved the rider's feet forward, where they rested on pegs or platforms. The new riding position was designed to increase rider comfort and control when using the motor for propulsion, and soon owners began relying on the gasoline motor for all but emergency use. Front suspension and (on some machines) rear suspension increased control at high speeds. By 1915, some manufacturers were omitting pedal propulsion entirely, resulting in the introduction of the first true modern motorcycle.
At the same time, purpose-built motorbikes like the Derny and VéloSoleX, with stronger frames and sometimes with only token ability to be wholly human-powered were introduced in France. Many years later, manufacturers would re-introduce this concept as the moped, a small motorcycle fitted with pedals that can be used as a starting aid but which cannot, practically, be ridden under pedal power alone.
In France, the gasoline-powered motorized bicycle, known popularly as the vélomoteur or vélomoto was popular during the 1930s, and continued to be widely sold in early postwar years as a means of transportation during a period of gasoline shortages and limited automobile production.
In the 1930s, the United Kingdom and its former colonies also developed "clip-on" motors for bicycles (35 to 49 cc), followed by the "Autocycle" with a purpose-built frame incorporating pedals and a two-stroke engine (often a 98 cc Villiers engine), but without a gearbox (e.g. the Malvern Star). Autocycle manufacturers were well established in countries such as Britain and Australia before World War II.