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108-506: Miyata is a Japanese manufacturer of bicycles , unicycles and fire extinguishers . The company has been in operation since 1890. Miyata was also one of the first producers of motorcycles in Japan under the name Asahi. The Asahi AA was the first mass-produced motorcycle in Japan. Miyata claims to have been the first Japanese manufacturer of flash-butt welded frame tubes (1946) and the first to use electrostatic painting (1950). Miyata

216-657: A frame , one behind the other. A bicycle rider is called a cyclist, or bicyclist. Bicycles were introduced in the 19th century in Europe . By the early 21st century there were more than 1 billion bicycles. There are many more bicycles than cars . Bicycles are the principal means of transport in many regions. They also provide a popular form of recreation , and have been adapted for use as children's toys . Bicycles are used for fitness , military and police applications, courier services , bicycle racing , and artistic cycling . The basic shape and configuration of

324-415: A power-valve system . The valves are normally in or around the exhaust ports. They work in one of two ways; either they alter the exhaust port by closing off the top part of the port, which alters port timing, such as Rotax R.A.V.E, Yamaha YPVS, Honda RC-Valve, Kawasaki K.I.P.S., Cagiva C.T.S., or Suzuki AETC systems, or by altering the volume of the exhaust, which changes the resonant frequency of

432-421: A rotary valve is that it enables the two-stroke engine's intake timing to be asymmetrical, which is not possible with piston-port type engines. The piston-port type engine's intake timing opens and closes before and after top dead center at the same crank angle, making it symmetrical, whereas the rotary valve allows the opening to begin and close earlier. Rotary valve engines can be tailored to deliver power over

540-534: A "women's" bicycle, step-through frames are not common for larger frames. Step-throughs were popular partly for practical reasons and partly for social mores of the day. For most of the history of bicycles' popularity women have worn long skirts, and the lower frame accommodated these better than the top-tube. Furthermore, it was considered "unladylike" for women to open their legs to mount and dismount—in more conservative times women who rode bicycles at all were vilified as immoral or immodest. These practices were akin to

648-460: A 'straight handlebar' or 'riser bar' with varying degrees of sweep backward and centimeters rise upwards, as well as wider widths which can provide better handling due to increased leverage against the wheel. Saddles also vary with rider preference, from the cushioned ones favored by short-distance riders to narrower saddles which allow more room for leg swings. Comfort depends on riding position. With comfort bikes and hybrids, cyclists sit high over

756-723: A 914 was a 9 series 14 speed. The Miyata brand still exists and, while it is no longer distributed in the United States, it had until 2010 a joint venture with the Dutch Koga brand, a Dutch bicycle manufacturer, established in Heerenveen Netherlands, under the name Koga-Miyata . Koga is part of the Accell Group since 1998. In late 2011, Miyata announced plans to once again sell bicycles under its own Miyata Japon brand. Its new frames were based on

864-421: A DKW design that proved reasonably successful employing loop charging. The original SAAB 92 had a two-cylinder engine of comparatively low efficiency. At cruising speed, reflected-wave, exhaust-port blocking occurred at too low a frequency. Using the asymmetrical three-port exhaust manifold employed in the identical DKW engine improved fuel economy. The 750-cc standard engine produced 36 to 42 hp, depending on

972-568: A French publication to describe an unidentified two-wheeled vehicle, possibly a carriage. The design of the bicycle was an advance on the velocipede , although the words were used with some degree of overlap for a time. Other words for bicycle include "bike", "pushbike", "pedal cycle", or "cycle". In Unicode , the code point for "bicycle" is 0x1F6B2. The entity 🚲 in HTML produces 🚲. Although bike and cycle are used interchangeably to refer mostly to two types of two-wheelers,

1080-474: A Scottish blacksmith, in 1839, although the claim is often disputed. He is also associated with the first recorded instance of a cycling traffic offense, when a Glasgow newspaper in 1842 reported an accident in which an anonymous "gentleman from Dumfries-shire... bestride a velocipede... of ingenious design" knocked over a little girl in Glasgow and was fined five shillings (equivalent to £30 in 2023). In

1188-481: A bicycle at low to medium speeds of around 16–24 km/h (10–15 mph) uses only the power required to walk. Air drag, which is proportional to the square of speed, requires dramatically higher power outputs as speeds increase. If the rider is sitting upright, the rider's body creates about 75% of the total drag of the bicycle/rider combination. Drag can be reduced by seating the rider in a more aerodynamically streamlined position. Drag can also be reduced by covering

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1296-496: A bike both stiff and compliant by manipulating the lay-up. Virtually all professional racing bicycles now use carbon fibre frames, as they have the best strength to weight ratio. A typical modern carbon fiber frame can weigh less than 1 kilogram (2.2 lb). Other exotic frame materials include titanium and advanced alloys. Bamboo , a natural composite material with high strength-to-weight ratio and stiffness has been used for bicycles since 1894. Recent versions use bamboo for

1404-569: A conventional rear wheel brake, but not as effective as a front wheel brake. Bicycle suspension refers to the system or systems used to suspend the rider and all or part of the bicycle. This serves two purposes: to keep the wheels in continuous contact with the ground, improving control, and to isolate the rider and luggage from jarring due to rough surfaces, improving comfort. Bicycle suspensions are used primarily on mountain bicycles, but are also common on hybrid bicycles, as they can help deal with problematic vibration from poor surfaces. Suspension

1512-448: A crossflow engine) is always best and support is good. In some engines, the small end is offset to reduce thrust in the intended rotational direction and the forward face of the piston has been made thinner and lighter to compensate, but when running backward, this weaker forward face suffers increased mechanical stress it was not designed to resist. This can be avoided by the use of crossheads and also using thrust bearings to isolate

1620-496: A cyclist to make fewer pedal turns to maintain a given speed, but with more effort per turn of the pedals. With a chain drive transmission, a chainring attached to a crank drives the chain, which in turn rotates the rear wheel via the rear sprocket(s) ( cassette or freewheel ). There are four gearing options: two-speed hub gear integrated with chain ring, up to 3 chain rings, up to 12 sprockets, hub gear built into rear wheel (3-speed to 14-speed). The most common options are either

1728-456: A good foothold in the bicycle market, becoming contracted by multiple local brands to build their bicycles and ultimately attracting Panasonic Corporation to become a shareholder in 1959. Panasonic Corporation , for a period the manufacturer of National and Panasonic brand bicycles, was Miyata's largest shareholder from 1959 until 2008, when it sold its remaining stake in Miyata. Throughout

1836-399: A high gear when cycling downhill, a medium gear when cycling on a flat road, and a low gear when cycling uphill. In a lower gear every turn of the pedals leads to fewer rotations of the rear wheel. This allows the energy required to move the same distance to be distributed over more pedal turns, reducing fatigue when riding uphill, with a heavy load, or against strong winds. A higher gear allows

1944-517: A key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings , pneumatic tires , chain-driven sprockets , and tension-spoked wheels . The word bicycle first appeared in English print in The Daily News in 1868, to describe "Bysicles and trysicles" on the "Champs Elysées and Bois de Boulogne". The word was first used in 1847 in

2052-491: A market for businesses selling imported machines, as well as domestic designs incorporating foreign components. Miyata produced the first all-Japanese motorcycle in 1913, also under the Asahi name, based on a British Triumph design. However, at the time motor vehicles were a luxury item and imported motorcycles were seen as fashionable and desirable over locally made machines, and the Asahi sold fewer than 40 units before production

2160-465: A narrow range of pedaling speeds, or cadence , a variable gear ratio helps a cyclist to maintain an optimum pedalling speed while covering varied terrain. Some, mainly utility, bicycles use hub gears with between 3 and 14 ratios, but most use the generally more efficient dérailleur system, by which the chain is moved between different cogs called chainrings and sprockets to select a ratio. A dérailleur system normally has two dérailleurs, or mechs, one at

2268-470: A patent in 1880 in Germany. The first truly practical two-stroke engine is attributed to Yorkshireman Alfred Angas Scott , who started producing twin-cylinder water-cooled motorcycles in 1908. Two-stroke gasoline engines with electrical spark ignition are particularly useful in lightweight or portable applications such as chainsaws and motorcycles. However, when weight and size are not an issue,

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2376-865: A proliferation of specialized bicycle types, improved bicycle safety , and riding comfort. Bicycles can be categorized in many different ways: by function, by number of riders, by general construction, by gearing or by means of propulsion. The more common types include utility bicycles , mountain bicycles , racing bicycles , touring bicycles , hybrid bicycles , cruiser bicycles , and BMX bikes . Less common are tandems , low riders , tall bikes , fixed gear , folding models , amphibious bicycles , cargo bikes , recumbents and electric bicycles . Unicycles , tricycles and quadracycles are not strictly bicycles, as they have respectively one, three and four wheels, but are often referred to informally as "bikes" or "cycles". A bicycle stays upright while moving forward by being steered so as to keep its center of mass over

2484-490: A rear hub or multiple chain rings combined with multiple sprockets (other combinations of options are possible but less common). The handlebars connect to the stem that connects to the fork that connects to the front wheel, and the whole assembly connects to the bike and rotates about the steering axis via the headset bearings. Three styles of handlebar are common. Upright handlebars , the norm in Europe and elsewhere until

2592-584: A sales agent of the Coventry Sewing Machine Company (which soon became the Coventry Machinists Company ), brought a Michaux cycle to Coventry , England. His uncle, Josiah Turner, and business partner James Starley , used this as a basis for the 'Coventry Model' in what became Britain's first cycle factory. The dwarf ordinary addressed some of these faults by reducing the front wheel diameter and setting

2700-449: A scavenging function. The units run in pairs, with the lower half of one piston charging an adjacent combustion chamber. The upper section of the piston still relies on total-loss lubrication, but the other engine parts are sump lubricated with cleanliness and reliability benefits. The mass of the piston is only about 20% more than a loop-scavenged engine's piston because skirt thicknesses can be less. Many modern two-stroke engines employ

2808-618: A similar pattern as in aircraft, the goal being high strength and low weight. Since the late 1930s alloy steels have been used for frame and fork tubes in higher quality machines. By the 1980s aluminum welding techniques had improved to the point that aluminum tube could safely be used in place of steel . Since then aluminum alloy frames and other components have become popular due to their light weight, and most mid-range bikes are now principally aluminum alloy of some kind. More expensive bikes use carbon fibre due to its significantly lighter weight and profiling ability, allowing designers to make

2916-658: A similar system. Traditional flywheel magnetos (using contact-breaker points, but no external coil) worked equally well in reverse because the cam controlling the points is symmetrical, breaking contact before top dead center equally well whether running forward or backward. Reed-valve engines run backward just as well as piston-controlled porting, though rotary valve engines have asymmetrical inlet timing and do not run very well. Serious disadvantages exist for running many engines backward under load for any length of time, and some of these reasons are general, applying equally to both two-stroke and four-stroke engines. This disadvantage

3024-518: A turbocharger. Crankcase-compression two-stroke engines, such as common small gasoline-powered engines, are lubricated by a petroil mixture in a total-loss system . Oil is mixed in with their petrol fuel beforehand, in a fuel-to-oil ratio of around 32:1. This oil then forms emissions, either by being burned in the engine or as droplets in the exhaust, historically resulting in more exhaust emissions, particularly hydrocarbons, than four-stroke engines of comparable power output. The combined opening time of

3132-567: A typical upright or "safety" bicycle , has changed little since the first chain-driven model was developed around 1885. However, many details have been improved, especially since the advent of modern materials and computer-aided design . These have allowed for a proliferation of specialized designs for many types of cycling. In the 21st century, electric bicycles have become popular. The bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that played

3240-511: A wheelset, especially in the context of ready-built "off the shelf", performance-oriented wheels. Tires vary enormously depending on their intended purpose. Road bicycles use tires 18 to 25 millimeters wide, most often completely smooth, or slick , and inflated to high pressure to roll fast on smooth surfaces. Off-road tires are usually between 38 and 64 mm (1.5 and 2.5 in) wide, and have treads for gripping in muddy conditions or metal studs for ice. Groupset generally refers to all of

3348-400: A wider speed range or higher power over a narrower speed range than either a piston-port or reed-valve engine. Where a portion of the rotary valve is a portion of the crankcase itself, of particular importance, no wear should be allowed to take place. In a cross-flow engine, the transfer and exhaust ports are on opposite sides of the cylinder, and a deflector on the top of the piston directs

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3456-413: Is accepted in most cases where cost, weight, and size are major considerations. The problem comes about because in "forward" running, the major thrust face of the piston is on the back face of the cylinder, which in a two-stroke particularly, is the coolest and best-lubricated part. The forward face of the piston in a trunk engine is less well-suited to be the major thrust face, since it covers and uncovers

3564-505: Is applied to brake levers mounted on the handlebars and transmitted via Bowden cables or hydraulic lines to the friction pads, which apply pressure to the braking surface, causing friction which slows the bicycle down. A rear hub brake may be either hand-operated or pedal-actuated, as in the back pedal coaster brakes which were popular in North America until the 1960s. Track bicycles do not have brakes, because all riders ride in

3672-422: Is attributed to Scottish engineer Dugald Clerk , who patented his design in 1881. However, unlike most later two-stroke engines, his had a separate charging cylinder. The crankcase -scavenged engine, employing the area below the piston as a charging pump, is generally credited to Englishman Joseph Day . On 31 December 1879, German inventor Karl Benz produced a two-stroke gas engine, for which he received

3780-534: Is being phased out. Honda , for instance, ceased selling two-stroke off-road motorcycles in the United States in 2007, after abandoning road-going models considerably earlier. Due to their high power-to-weight ratio and ability to be used in any orientation, two-stroke engines are common in handheld outdoor power tools including leaf blowers , chainsaws , and string trimmers . Two-stroke diesel engines are found mostly in large industrial and marine applications, as well as some trucks and heavy machinery. Although

3888-574: Is common in on-road, off-road, and stationary two-stroke engines ( Detroit Diesel ), certain small marine two-stroke engines ( Gray Marine Motor Company , which adapted the Detroit Diesel Series 71 for marine use ), certain railroad two-stroke diesel locomotives ( Electro-Motive Diesel ) and large marine two-stroke main propulsion engines ( Wärtsilä ). Ported types are represented by the opposed piston design in which two pistons are in each cylinder, working in opposite directions such as

3996-445: Is especially important on recumbent bicycles, since while an upright bicycle rider can stand on the pedals to achieve some of the benefits of suspension, a recumbent rider cannot. Basic mountain bicycles and hybrids usually have front suspension only, whilst more sophisticated ones also have rear suspension. Road bicycles tend to have no suspension. The wheel axle fits into fork ends in the frame and fork. A pair of wheels may be called

4104-432: Is that the two-stroke's crankcase is sealed and forms part of the induction process in gasoline and hot-bulb engines . Diesel two-strokes often add a Roots blower or piston pump for scavenging . The reed valve is a simple but highly effective form of check valve commonly fitted in the intake tract of the piston-controlled port. It allows asymmetric intake of the fuel charge, improving power and economy, while widening

4212-471: Is the most efficient human-powered means of transportation in terms of energy a person must expend to travel a given distance. From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels, although the use of gearing mechanisms may reduce this by 10–15%. In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also an efficient means of cargo transportation. A human traveling on

4320-409: Is under every circumstance more efficient than cross-flow scavenging. In a uniflow engine, the mixture, or "charge air" in the case of a diesel, enters at one end of the cylinder controlled by the piston and the exhaust exits at the other end controlled by an exhaust valve or piston. The scavenging gas-flow is, therefore, in one direction only, hence the name uniflow. The design using exhaust valve(s)

4428-652: The Giro d'Italia , the Tour de France , the Vuelta a España , the Tour de Pologne , and the Volta a Portugal . They are also used for entertainment and pleasure in other ways, such as in organised mass rides, artistic cycling and freestyle BMX . The bicycle has undergone continual adaptation and improvement since its inception. These innovations have continued with the advent of modern materials and computer-aided design, allowing for

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4536-514: The HA and the Golden Beam FA/2 , both with a 249cc four-stroke motor, as well as a model with a 344cc single-cylinder motor, and various two-cylinder two-stroke motors. Miyata manufactured its last motorcycles in 1964. Many say Miyata pioneered triple butting, and revolutionized frame building techniques. The first Miyatas were bolt-upright town bikes. Over the decades, Miyata established

4644-947: The Honda Super Cub motorcycle, has more than 100 million units made, while most produced car, the Toyota Corolla , has reached 44 million and counting. Bicycles are used for transportation, bicycle commuting , and utility cycling . They are also used professionally by mail carriers , paramedics , police , messengers , and general delivery services. Military uses of bicycles include communications , reconnaissance , troop movement, supply of provisions, and patrol, such as in bicycle infantries . They are also used for recreational purposes, including bicycle touring , mountain biking , physical fitness , and play . Bicycle sports include racing , BMX racing , track racing , criterium , roller racing , sportives and time trials . Major multi-stage professional events are

4752-690: The Imperial Japanese Army including the Murata rifle , and knives for the Navy . In 1889, a foreigner visited Miyata to ask the gunmakers to repair his bicycle. The engineers repaired the bicycle, and the company began to repair bicycles as a side business. In 1890, Miyata opened a new factory in Kikukawa, and the company was renamed Miyata Gun Works . Eitarō manufactured the first Miyata prototype bicycle in 1890, using rifle barrels produced at

4860-464: The Junkers Jumo 205 and Napier Deltic . The once-popular split-single design falls into this class, being effectively a folded uniflow. With advanced-angle exhaust timing, uniflow engines can be supercharged with a crankshaft-driven blower, either piston or Roots-type. The piston of this engine is "top-hat"-shaped; the upper section forms the regular cylinder, and the lower section performs

4968-553: The Second Sino-Japanese War broke out in 1937 resources and materials for motorcycle construction became increasingly scarce, and in 1939 Miyata's Kamata plant was converted by the government to produce components for military aircraft. The AA sold an estimated 40,000 units from 1933-39. Miyata again resumed production of motorcycles after the Second World War . Through the 1950s the company released

5076-503: The World Fair and was produced in a few thousand units. In the 1870s many cycling clubs flourished. They were popular in a time when there were no cars on the market and the principal mode of transportation was horse-drawn vehicles , such the horse and buggy or the horsecar . Among the earliest clubs was The Bicycle Touring Club , which has operated since 1878. By the turn of the century, cycling clubs flourished on both sides of

5184-512: The expansion chamber , such as the Suzuki SAEC and Honda V-TACS system. The result is an engine with better low-speed power without sacrificing high-speed power. However, as power valves are in the hot gas flow, they need regular maintenance to perform well. Direct injection has considerable advantages in two-stroke engines. In carburetted two-strokes, a major problem is a portion of the fuel/air mixture going directly out, unburned, through

5292-479: The oil reservoir does not depend on gravity. A number of mainstream automobile manufacturers have used two-stroke engines in the past, including the Swedish Saab , German manufacturers DKW , Auto-Union , VEB Sachsenring Automobilwerke Zwickau , VEB Automobilwerk Eisenach , and VEB Fahrzeug- und Jagdwaffenwerk , and Polish manufacturers FSO and FSM . The Japanese manufacturers Suzuki and Subaru did

5400-407: The seat further back. This, in turn, required gearing—effected in a variety of ways—to efficiently use pedal power. Having to both pedal and steer via the front wheel remained a problem. Englishman J.K. Starley (nephew of James Starley), J.H. Lawson, and Shergold solved this problem by introducing the chain drive (originated by the unsuccessful "bicyclette" of Englishman Henry Lawson), connecting

5508-522: The seat tube was added which created the modern bike's double-triangle diamond frame . Further innovations increased comfort and ushered in a second bicycle craze , the 1890s Golden Age of Bicycles . In 1888, Scotsman John Boyd Dunlop introduced the first practical pneumatic tire, which soon became universal. Willie Hume demonstrated the supremacy of Dunlop's tyres in 1889, winning the tyre's first-ever races in Ireland and then England. Soon after,

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5616-416: The 1000 model were touring bicycles, with the level of bicycle increasing with first digit in the series. In general, a 200 series touring bicycle would be roughly equivalent to a 300 series competition/fitness bicycle in terms of component levels, frame materials and value. 300, 400, 500, 700, 900 series were mid-range competition/fitness bicycles — with the level of quality increasing with first digit in

5724-528: The 1960s due in no small way to the increased power afforded by loop scavenging. An additional benefit of loop scavenging was the piston could be made nearly flat or slightly domed, which allowed the piston to be appreciably lighter and stronger, and consequently to tolerate higher engine speeds. The "flat top" piston also has better thermal properties and is less prone to uneven heating, expansion, piston seizures, dimensional changes, and compression losses. SAAB built 750- and 850-cc three-cylinder engines based on

5832-407: The 1960s, especially for motorcycles, but for smaller or slower engines using direct injection, the deflector piston can still be an acceptable approach. This method of scavenging uses carefully shaped and positioned transfer ports to direct the flow of fresh mixture toward the combustion chamber as it enters the cylinder. The fuel/air mixture strikes the cylinder head , then follows the curvature of

5940-443: The 1970s, curve gently back toward the rider, offering a natural grip and comfortable upright position. Drop handlebars "drop" as they curve forward and down, offering the cyclist best braking power from a more aerodynamic "crouched" position, as well as more upright positions in which the hands grip the brake lever mounts, the forward curves, or the upper flat sections for increasingly upright postures. Mountain bikes generally feature

6048-520: The Atlantic, and touring and racing became widely popular. The Raleigh Bicycle Company was founded in Nottingham, England in 1888. It became the biggest bicycle manufacturing company in the world, making over two million bikes per year. Bicycles and horse buggies were the two mainstays of private transportation just prior to the automobile, and the grading of smooth roads in the late 19th century

6156-452: The German inventor of an early form in the mid-1920s, it became widely adopted in Germany country during the 1930s and spread further afield after World War II . Loop scavenging is the most common type of fuel/air mixture transfer used on modern two-stroke engines. Suzuki was one of the first manufacturers outside of Europe to adopt loop-scavenged, two-stroke engines. This operational feature

6264-511: The Kansai Prefectural Association Exhibition in 1910. The first Asahi automobile was a two-passenger car with an air-cooled, two-cylinder engine. Motorcycles gained popularity in Japan in the early years of the 20th century as foreigners began bringing British and German machines to the country. The Japanese government officially allowed commercial import of foreign motorcycles beginning in 1909, creating

6372-588: The Koga Miyata frame on which Peter Winnen won the Alpe d'Huez stage of the 1981 Tour de France . Each custom-ordered frame was to be hand-built and made with Miyata's traditional chromoly steel process, featuring Campagnolo components, at its Chigasaki factory. Bicycle A bicycle , also called a pedal cycle , bike , push-bike or cycle , is a human-powered or motor-assisted , pedal-driven , single-track vehicle , with two wheels attached to

6480-424: The U.S. bike boom of the 1970s and into the 1980s, Miyata competed with American companies including Schwinn , Huffy , and Murray ; European companies including Raleigh , Peugeot and Motobecane — as well as other nascent Japanese brands including Nishiki , Fuji , Bridgestone , Centurion , Lotus and Univega — whose bikes were manufactured by Miyata. Japanese-manufactured bikes succeeded in

6588-521: The U.S. market until currency fluctuations in the late 1980s made them less competitive, leading companies to source bicycles from Taiwan. Late 1970s to mid-1980s Miyata bikes have high-quality Japanese lugged steel frames and Shimano or Suntour components. Miyata models carried numeric names (e.g., Miyata 710 ). By the late 1970s Miyata began using the same names, writing out the numeric names (e.g., Miyata Seven Ten ). Generally, 90 and 100 series were sports/entry level bicycles. 200 and 600 series and

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6696-577: The best known being the rod-driven velocipede by Scotsman Thomas McCall in 1869. In that same year, bicycle wheels with wire spokes were patented by Eugène Meyer of Paris. The French vélocipède , made of iron and wood, developed into the " penny-farthing " (historically known as an "ordinary bicycle", a retronym , since there was then no other kind). It featured a tubular steel frame on which were mounted wire-spoked wheels with solid rubber tires. These bicycles were difficult to ride due to their high seat and poor weight distribution . In 1868 Rowley Turner,

6804-447: The bicycle with an aerodynamic fairing . The fastest recorded unpaced speed on a flat surface is 144.18 km/h (89.59 mph). In addition, the carbon dioxide generated in the production and transportation of the food required by the bicyclist, per mile traveled, is less than 1 ⁄ 10 that generated by energy efficient motorcars. The great majority of modern bicycles have a frame with upright seating that looks much like

6912-405: The bicycle. Short-wheelbase or tall bicycles, when braking, can generate enough stopping force at the front wheel to flip longitudinally. The act of purposefully using this force to lift the rear wheel and balance on the front without tipping over is a trick known as a stoppie , endo, or front wheelie. The bicycle is extraordinarily efficient in both biological and mechanical terms. The bicycle

7020-423: The bore diameter for reasonable piston ring life. Beyond this, the piston rings bulge into the exhaust port and wear quickly. A maximum 70% of bore width is possible in racing engines, where rings are changed every few races. Intake duration is between 120 and 160°. Transfer port time is set at a minimum of 26°. The strong, low-pressure pulse of a racing two-stroke expansion chamber can drop the pressure to -7 psi when

7128-459: The combustion chamber, and then is deflected downward. This not only prevents the fuel/air mixture from traveling directly out the exhaust port, but also creates a swirling turbulence which improves combustion efficiency , power, and economy. Usually, a piston deflector is not required, so this approach has a distinct advantage over the cross-flow scheme (above). Often referred to as "Schnuerle" (or "Schnürle") loop scavenging after Adolf Schnürle,

7236-844: The components that make up a bicycle excluding the bicycle frame, fork, stem, wheels, tires, and rider contact points, such as the saddle and handlebars. Two-stroke engine Two-stroke engines often have a higher power-to-weight ratio than a four-stroke engine, since their power stroke occurs twice as often. Two-stroke engines can also have fewer moving parts , and thus be cheaper to manufacture and weigh less. In countries and regions with stringent emissions regulation, two-stroke engines have been phased out in automotive and motorcycle uses. In regions where regulations are less stringent, small displacement two-stroke engines remain popular in mopeds and motorcycles. They are also used in power tools such as chainsaws and leaf blowers . The first commercial two-stroke engine involving cylinder compression

7344-453: The crankshaft commonly spins in the same axis and direction as do the wheels i.e. "forward". Some of the considerations discussed here apply to four-stroke engines (which cannot reverse their direction of rotation without considerable modification), almost all of which spin forward, too. It is also useful to note that the "front" and "back" faces of the piston are - respectively - the exhaust port and intake port sides of it, and are not to do with

7452-415: The cycle's potential for high thermodynamic efficiency makes it ideal for diesel compression ignition engines operating in large, weight-insensitive applications, such as marine propulsion , railway locomotives , and electricity generation . In a two-stroke engine, the exhaust gases transfer less heat to the cooling system than a four-stroke, which means more energy to drive the piston, and if present,

7560-413: The early 1860s, Frenchmen Pierre Michaux and Pierre Lallement took bicycle design in a new direction by adding a mechanical crank drive with pedals on an enlarged front wheel (the velocipede ). This was the first in mass production. Another French inventor named Douglas Grasso had a failed prototype of Pierre Lallement's bicycle several years earlier. Several inventions followed using rear-wheel drive,

7668-400: The engine from end loads. Large two-stroke ship diesels are sometimes made to be reversible. Like four-stroke ship engines (some of which are also reversible), they use mechanically operated valves, so require additional camshaft mechanisms. These engines use crossheads to eliminate sidethrust on the piston and isolate the under-piston space from the crankcase. On top of other considerations,

7776-415: The exhaust port in the cylinder, the hottest part of the engine, where piston lubrication is at its most marginal. The front face of the piston is also more vulnerable since the exhaust port, the largest in the engine, is in the front wall of the cylinder. Piston skirts and rings risk being extruded into this port, so having them pressing hardest on the opposite wall (where there are only the transfer ports in

7884-409: The exhaust port, and direct injection effectively eliminates this problem. Two systems are in use: low-pressure air-assisted injection and high-pressure injection. Since the fuel does not pass through the crankcase, a separate source of lubrication is needed. For the purpose of this discussion, it is convenient to think in motorcycle terms, where the exhaust pipe faces into the cooling air stream, and

7992-479: The factory. The early success of Miyata's bicycles was boosted by a request in 1892 from crown prince Yoshihito (later Emperor Taishō ) to build him a bicycle. Nonetheless, Miyata halted production of bicycles to focus exclusively on arms manufacture during the First Sino-Japanese War of 1894-95. Japan changed its laws in 1900 to allow the import of foreign rifles, and the subsequent flooding of

8100-406: The first chain-driven bike. These upright bicycles almost always feature the diamond frame , a truss consisting of two triangles: the front triangle and the rear triangle. The front triangle consists of the head tube, top tube, down tube, and seat tube. The head tube contains the headset , the set of bearings that allows the fork to turn smoothly for steering and balance. The top tube connects

8208-496: The frame-mounted cranks to the rear wheel. These models were known as safety bicycles , dwarf safeties, or upright bicycles for their lower seat height and better weight distribution, although without pneumatic tires the ride of the smaller-wheeled bicycle would be much rougher than that of the larger-wheeled variety. Starley's 1885 Rover , manufactured in Coventry is usually described as the first recognizably modern bicycle. Soon

8316-413: The fresh intake charge into the upper part of the cylinder, pushing the residual exhaust gas down the other side of the deflector and out the exhaust port. The deflector increases the piston's weight and exposed surface area, and the fact that it makes piston cooling and achieving an effective combustion chamber shape more difficult is why this design has been largely superseded by uniflow scavenging after

8424-446: The front to select the chainring and another at the back to select the sprocket. Most bikes have two or three chainrings, and from 5 to 11 sprockets on the back, with the number of theoretical gears calculated by multiplying front by back. In reality, many gears overlap or require the chain to run diagonally, so the number of usable gears is fewer. An alternative to chaindrive is to use a synchronous belt. These are toothed and work much

8532-410: The head tube to the seat tube at the top, and the down tube connects the head tube to the bottom bracket . The rear triangle consists of the seat tube and paired chain stays and seat stays. The chain stays run parallel to the chain , connecting the bottom bracket to the rear dropout , where the axle for the rear wheel is held. The seat stays connect the top of the seat tube (at or near the same point as

8640-443: The intake and exhaust ports in some two-stroke designs can also allow some amount of unburned fuel vapors to exit in the exhaust stream. The high combustion temperatures of small, air-cooled engines may also produce NO x emissions. Two-stroke gasoline engines are preferred when mechanical simplicity, light weight, and high power-to-weight ratio are design priorities. By mixing oil with fuel, they can operate in any orientation as

8748-638: The market with cheap imports hurt Miyata's business badly. Upon Eisuke's death on 6 June, Eitarō converted the business entirely to bicycle manufacturing, producing bicycles under the Asahi and Pāson brands. Miyata's entire production of Asahi bicycles was purchased by the Imperial Army until the end of the Russo-Japanese War in 1905. Miyata began developing automobile technology in 1907. Miyata's first automobile, also named Asahi, debuted at

8856-402: The mechanism is contained within the wheel hub, or disc brakes, where pads act on a rotor attached to the hub. Most road bicycles use rim brakes, but some use disc brakes. Disc brakes are more common for mountain bikes, tandems and recumbent bicycles than on other types of bicycles, due to their increased power, coupled with an increased weight and complexity. With hand-operated brakes, force

8964-475: The model year. The Monte Carlo Rally variant, 750-cc (with a filled crankshaft for higher base compression), generated 65 hp. An 850-cc version was available in the 1966 SAAB Sport (a standard trim model in comparison to the deluxe trim of the Monte Carlo). Base compression comprises a portion of the overall compression ratio of a two-stroke engine. Work published at SAE in 2012 points that loop scavenging

9072-399: The oil pump of a modern two-stroke may not work in reverse, in which case the engine suffers oil starvation within a short time. Running a motorcycle engine backward is relatively easy to initiate, and in rare cases, can be triggered by a back-fire. It is not advisable. Model airplane engines with reed valves can be mounted in either tractor or pusher configuration without needing to change

9180-543: The older practice of riding horse sidesaddle . Another style is the recumbent bicycle . These are inherently more aerodynamic than upright versions, as the rider may lean back onto a support and operate pedals that are on about the same level as the seat. The world's fastest bicycle is a recumbent bicycle but this type was banned from competition in 1934 by the Union Cycliste Internationale . Historically, materials used in bicycles have followed

9288-487: The other - the inlet pipe having passage to the crankcase only when the two cutouts coincide. The crankshaft itself may form one of the members, as in most glow-plug model engines. In another version, the crank disc is arranged to be a close-clearance fit in the crankcase, and is provided with a cutout that lines up with an inlet passage in the crankcase wall at the appropriate time, as in Vespa motor scooters. The advantage of

9396-424: The overall weight of the bicycle. A recumbent bicycle has a reclined chair-like seat that some riders find more comfortable than a saddle, especially riders who suffer from certain types of seat, back, neck, shoulder, or wrist pain. Recumbent bicycles may have either under-seat or over-seat steering . Bicycle brakes may be rim brakes, in which friction pads are compressed against the wheel rims; hub brakes, where

9504-434: The piston covering and uncovering the ports as it moves up and down in the cylinder. In the 1970s, Yamaha worked out some basic principles for this system. They found that, in general, widening an exhaust port increases the power by the same amount as raising the port, but the power band does not narrow as it does when the port is raised. However, a mechanical limit exists to the width of a single exhaust port, at about 62% of

9612-440: The piston is at bottom dead center, and the transfer ports nearly wide open. One of the reasons for high fuel consumption in two-strokes is that some of the incoming pressurized fuel-air mixture is forced across the top of the piston, where it has a cooling action, and straight out the exhaust pipe. An expansion chamber with a strong reverse pulse stops this outgoing flow. A fundamental difference from typical four-stroke engines

9720-550: The power band. Such valves are widely used in motorcycle, ATV, and marine outboard engines. The intake pathway is opened and closed by a rotating member. A familiar type sometimes seen on small motorcycles is a slotted disk attached to the crankshaft , which covers and uncovers an opening in the end of the crankcase, allowing charge to enter during one portion of the cycle (called a disc valve). Another form of rotary inlet valve used on two-stroke engines employs two cylindrical members with suitable cutouts arranged to rotate one within

9828-490: The primary frame with glued metal connections and parts, priced as exotic models. The drivetrain begins with pedals which rotate the cranks , which are held in axis by the bottom bracket. Most bicycles use a chain to transmit power to the rear wheel. A very small number of bicycles use a shaft drive to transmit power, or special belts. Hydraulic bicycle transmissions have been built, but they are currently inefficient and complex. Since cyclists' legs are most efficient over

9936-466: The principles remain the same, the mechanical details of various two-stroke engines differ depending on the type. The design types vary according to the method of introducing the charge to the cylinder, the method of scavenging the cylinder (exchanging burnt exhaust for fresh mixture) and the method of exhausting the cylinder. Piston port is the simplest of the designs and the most common in small two-stroke engines. All functions are controlled solely by

10044-530: The rear freewheel was developed, enabling the rider to coast. This refinement led to the 1890s invention of coaster brakes . Dérailleur gears and hand-operated Bowden cable -pull brakes were also developed during these years, but were only slowly adopted by casual riders. The Svea Velocipede with vertical pedal arrangement and locking hubs was introduced in 1892 by the Swedish engineers Fredrik Ljungström and Birger Ljungström . It attracted attention at

10152-466: The rider to mount and dismount in a dignified way while wearing a skirt or dress. While some women's bicycles continue to use this frame style, there is also a variation, the mixte , which splits the top tube laterally into two thinner top tubes that bypass the seat tube on each side and connect to the rear fork ends. The ease of stepping through is also appreciated by those with limited flexibility or other joint problems. Because of its persistent image as

10260-402: The same as a chain—popular with commuters and long distance cyclists they require little maintenance. They cannot be shifted across a cassette of sprockets, and are used either as single speed or with a hub gear. Different gears and ranges of gears are appropriate for different people and styles of cycling. Multi-speed bicycles allow gear selection to suit the circumstances: a cyclist could use

10368-416: The same direction around a track which does not necessitate sharp deceleration. Track riders are still able to slow down because all track bicycles are fixed-gear, meaning that there is no freewheel. Without a freewheel, coasting is impossible, so when the rear wheel is moving, the cranks are moving. To slow down, the rider applies resistance to the pedals, acting as a braking system which can be as effective as

10476-821: The same in the 1970s. Production of two-stroke cars ended in the 1980s in the West, due to increasingly stringent regulation of air pollution . Eastern Bloc countries continued until around 1991, with the Trabant and Wartburg in East Germany. Two-stroke engines are still found in a variety of small propulsion applications, such as outboard motors , small on- and off-road motorcycles , mopeds , motor scooters , motorized bicycles , tuk-tuks , snowmobiles , go-karts , RC cars , ultralight and model airplanes. Particularly in developed countries, pollution regulations have meant that their use for many of these applications

10584-604: The seat, their weight directed down onto the saddle, such that a wider and more cushioned saddle is preferable. For racing bikes where the rider is bent over, weight is more evenly distributed between the handlebars and saddle, the hips are flexed, and a narrower and harder saddle is more efficient. Differing saddle designs exist for male and female cyclists, accommodating the genders' differing anatomies and sit bone width measurements, although bikes typically are sold with saddles most appropriate for men. Suspension seat posts and seat springs provide comfort by absorbing shock but can add to

10692-401: The series. The top line, pro series bicycles were named non-numerically (e.g., Team Miyata and Pro Miyata). 1000 series and X000 series bicycles, with the notable exception of the 1000 touring model, were competition/fitness models with non-ferrous frames. Often (but not always) the last two digits of the model number indicated the number of available gears, e.g., 912 was a 9-series 12 speed and

10800-456: The terms still vary across the world. In India, for example, a cycle refers only to a two-wheeler using pedal power whereas the term bike is used to describe a two-wheeler using internal combustion engine or electric motors as a source of motive power instead of motorcycle/motorbike. The " dandy horse ", also called Draisienne or Laufmaschine ("running machine"), was the first human means of transport to use only two wheels in tandem and

10908-520: The top or bottom of the piston. Regular gasoline two-stroke engines can run backward for short periods and under light load with little problem, and this has been used to provide a reversing facility in microcars , such as the Messerschmitt KR200 , that lacked reverse gearing. Where the vehicle has electric starting, the motor is turned off and restarted backward by turning the key in the opposite direction. Two-stroke golf carts have used

11016-446: The top tube) to the rear fork ends. Historically, women's bicycle frames had a top tube that connected in the middle of the seat tube instead of the top, resulting in a lower standover height at the expense of compromised structural integrity, since this places a strong bending load in the seat tube, and bicycle frame members are typically weak in bending. This design, referred to as a step-through frame or as an open frame , allows

11124-407: The wheels. This steering is usually provided by the rider, but under certain conditions may be provided by the bicycle itself. The combined center of mass of a bicycle and its rider must lean into a turn to successfully navigate it. This lean is induced by a method known as countersteering , which can be performed by the rider turning the handlebars directly with the hands or indirectly by leaning

11232-555: Was discontinued in 1916. Over the next two decades, Japanese manufacturers caught up to imported brands, and the rise of motorsports and motor clubs made motorcycles more accessible to the Japanese public. Miyata returned to motorcycle production with the Asahi AA in 1933. The AA was the first mass-produced Japanese motorcycle, and was highly successful, leading to construction of a new plant at Kamata in 1938. However, after

11340-461: Was founded by Eisuke Miyata (宮田栄助 1840-1900), a bowyer and engineer from Tokyo who also made components for rickshaws . Eisuke's second son, Eitarō, apprenticed in a local munitions facility and later earned a degree in mechanical engineering from Kyoto University . In 1874, Eisuke moved the family to Shiba and in 1881 opened Miyata Manufacturing in Kyōbashi, Tokyo . The factory produced guns for

11448-695: Was invented by the German Baron Karl von Drais . It is regarded as the first bicycle and von Drais is seen as the "father of the bicycle", but it did not have pedals. Von Drais introduced it to the public in Mannheim in 1817 and in Paris in 1818. Its rider sat astride a wooden frame supported by two in-line wheels and pushed the vehicle along with his or her feet while steering the front wheel. The first mechanically propelled, two-wheeled vehicle may have been built by Kirkpatrick MacMillan ,

11556-514: Was stimulated by the widespread advertising, production, and use of these devices. More than 1 billion bicycles have been manufactured worldwide as of the early 21st century. Bicycles are the most common vehicle of any kind in the world, and the most numerous model of any kind of vehicle, whether human-powered or motor vehicle , is the Chinese Flying Pigeon , with numbers exceeding 500 million. The next most numerous vehicle,

11664-485: Was used in conjunction with the expansion chamber exhaust developed by German motorcycle manufacturer, MZ, and Walter Kaaden. Loop scavenging, disc valves, and expansion chambers worked in a highly coordinated way to significantly increase the power output of two-stroke engines, particularly from the Japanese manufacturers Suzuki, Yamaha, and Kawasaki. Suzuki and Yamaha enjoyed success in Grand Prix motorcycle racing in

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