There are many systems for classifying types of motorcycles, describing how the motorcycles are put to use, or the designer's intent, or some combination of the two. Six main categories are widely recognized: cruiser, sport, touring, standard, dual-purpose, and dirt bike. Sometimes sport touring motorcycles are recognized as a seventh category. Strong lines are sometimes drawn between motorcycles and their smaller cousins, mopeds, scooters, and underbones, but other classification schemes include these as types of motorcycles.
There is no universal system for classifying all types of motorcycles. There are strict classification systems enforced by competitive motorcycle sport sanctioning bodies, or legal definitions of a motorcycle established by certain legal jurisdictions for motorcycle registration, emissions, road traffic safety rules or motorcyclist licensing. There are also informal classifications or nicknames used by manufacturers, riders, and the motorcycling media. Some experts do not recognize sub-types, like naked bike, that "purport to be classified" outside the six usual classes, because they fit within one of the main types and are recognizable only by cosmetic changes.
Street motorcycles are motorcycles designed for being ridden on paved roads. They have smooth tires with a light tread pattern and engines generally in the 125 cc (7.6 cu in) and over range. Most are capable of speeds up to 100 mph (160 km/h), and many of speeds in excess of 125 mph (201 km/h).
Standards, also called naked bikes or roadsters, are versatile, general-purpose street motorcycles. They are recognized primarily by their upright riding position, partway between the reclining rider posture of the cruisers and the forward leaning sport bikes. Footpegs are below the rider and handlebars are high enough to not force the rider to reach too far forward, placing the shoulders above the hips in a natural position. Because of their flexibility, lower costs, and moderate engine output, standards are particularly suited to motorcycle beginners.
Standards usually do not come with fairings or windscreens, or if they have them, they are relatively small. Standard is often a synonym for naked bike, a term that became popular in the 1990s in response to the proliferation of fully faired sport bikes. The standard seemed to have disappeared, fueling nostalgia for the return of the Universal Japanese Motorcycle, which were admired for their simplicity, quality, and versatility.
Muscle bike is a nickname for a motorcycle type, derived from either a standard or sport bike design, that puts a disproportionately high priority on engine power. Roadster is equivalent to standard or naked.
Cruisers are styled after American machines from the 1930s to the early 1960s, such as those made by Harley-Davidson, Indian, and Excelsior-Henderson. Harley-Davidsons largely define the cruiser category, and large-displacement V-twin engines are the norm, although other engine configurations and small to medium displacements also exist. Their engines are tuned for low-end torque, making them less demanding to ride because it is not necessary to shift as frequently to accelerate or maintain control.
The riding position places the feet forward and the hands are up relatively high, so that the spine is erect or leaning back slightly. At low to moderate speeds, cruisers are more comfortable than other styles, but riding for long periods at freeway speeds can lead to fatigue from pulling back on the handlebars to resist the force of the wind against the rider's chest. Cruisers have limited cornering ability due to a lack of ground clearance.
Choppers are a type of cruiser, so called because they are a "chopped", or cut-down, version of a production cruiser. Choppers are usually custom projects that result in a bike modified to suit the owner's ideals, and, as such, are a source of pride and accomplishment. Stereotypically, a chopper may have raked-out forks, small fuel tanks and high handlebars. Choppers were popularised in the Peter Fonda film Easy Rider. Being designed primarily for visual effect, choppers will not usually be the most efficient riding machines.
Power cruiser is a name used to distinguish bikes in the cruiser class that have significantly higher levels of power. They often come with upgraded brakes and suspensions, better ground clearance, and premium surface finishes, as well as more exotic or non-traditional styling.
Sport bikes emphasize top speed, acceleration, braking, handling and grip on paved roads, typically at the expense of comfort and fuel economy in comparison to less specialized motorcycles. Because of this, there are certain design elements that most motorcycles of this type will share. Sport bikes have comparatively high performance engines resting inside a lightweight frame. Inline-four engines dominate the sport bike category, with V-twins having a significant presence, and nearly every other engine configuration appearing in small numbers at one time or another. The combination of these elements helps maintain structural integrity and chassis rigidity. Braking systems combine higher performance brake pads and multi-piston calipers that clamp onto oversized vented rotors. Suspension systems are advanced in terms of adjustments and materials for increased stability and durability. Most sport bikes have fairings, often completely enclosing the engine, and windscreens that effectively deflect the air at very high speeds, or at least reduce overall drag.
Sport bikes have high footpegs that position the legs closer to the body to improve ground clearance when cornering, and a long reach to the hand controls, which positions the body and center of gravity forward, above the fuel tank. The rider leans forward into the wind, the force of which can comfortably support the rider's weight at speeds near 100 mph (160 km/h), but at lower speeds leaves too much weight on the arms and wrists, causing fatigue.
Streetfighters are derived from sport bikes, originally being customized sport bikes with the fairings removed and higher handlebars replacing the low clip-on handlebars. Since the 1990s, factory streetfighters have been produced. As with naked bike and muscle bike (below), the name streetfighter is used to help clarify the middle ground occupied by designs that blend elements of both sport bikes and standards.
Although any motorcycle can be equipped and used for touring, touring motorcycles are specifically designed to excel at covering long distances. They have large-displacement engines, fairings and screens that offer good weather and wind protection, large-capacity fuel tanks for long ranges between fill-ups, and a relaxed, upright seating position. Passenger accommodation is excellent and expansive luggage space is the norm for this class. Such bikes can have wet weights of 850–900 lb (390–410 kg) and top 1,300–1,400 lb (590–640 kg) fully loaded with a rider, passenger and gear.
Bagger, full dresser, full dress tourer, or dresser are various names for touring motorcycles, sometimes used disparagingly or jocularly, and originally referring to a Harley-Davidson or other cruisers with full sets of saddlebags. This can now refer to any touring motorcycle.
Sport touring motorcycles combine attributes of sport bikes and touring motorcycles. The rider posture is less extreme than a sport bike, giving greater long-distance comfort. Accommodation for a passenger is superior to a sport bike as well, along with increased luggage capacity. Being lighter, at 550–720 lb (250–330 kg) wet, than a pure touring bike and often having racier engines, suspensions, and brakes, sport tourers corner better and are more at home being aggressively ridden on curvy canyon roads. The distinction between touring and sport touring is not always clear as some manufacturers will list the same bike in either category in different markets. The Honda ST1300 Pan-European, for example, was listed by Honda as a sport touring motorcycle in the United States and Australia, but as a touring motorcycle in Europe.
Dual-sports, sometimes called dual-purpose or on/off-road motorcycles, are street legal machines that are also designed to enter off-road situations. Typically based on a dirt bike chassis, they have added lights, mirrors, signals, and instruments that allow them to be licensed for public roads. They are higher than other street bikes, with a high center of gravity and tall seat height, allowing good suspension travel for rough ground.
Adventure motorcycles are motorcycles with touring capability on paved and unpaved roads. As a dual-sport they have a significant on-pavement bias and perform well on pavement at higher speeds unlike most dual-sports. Their size, weight and sometimes their tires, however, limits their off-road capability. Most adventure motorcycles function well on graded dirt and gravel roads but are less than ideal on more difficult off-pavement terrain.
Supermoto motorcycles were designed to compete on a single course that alternated between three genres of motorcycle racing: road racing, track racing, and motocross. This increasingly popular type of motorcycle is often a dual-sport that has been fitted by the manufacturer with smaller rims and road tires. Supermotos are quickly gaining popularity as street bikes due to their combination of light weight, durability, relatively low cost, and sporty handling.
Scooter engine sizes range smaller than motorcycles, 50–850 cc (3.1–51.9 cu in), and have all-enclosing bodywork that makes them cleaner and quieter than motorcycles, as well as having more built-in storage space. Automatic clutches and continuously variable transmissions (CVT) make them easier to learn on and to ride. Scooters usually have smaller wheels than motorcycles. Scooters usually have the engine as part of the swingarm, so that their engines travel up and down with the suspension.
Underbones are small-displacement motorcycles with a step-through frame, descendants of the original Honda Super Cub. They are differentiated from scooters by their larger wheels and their use of footpegs instead of a floorboard. They often have a gear shifter with an automatic clutch.
The moped used to be a hybrid of the bicycle and the motorcycle, equipped with a small engine (usually a small two-stroke engine up to 50 cc, but occasionally an electric motor) and a bicycle drivetrain, and motive power can be supplied by the engine, the rider, or both. There is also Sport mopeds – a type of moped that resembles a sport bike.
In many places, mopeds are subject to less stringent licensing than bikes with larger engines and are popular as very cheap motorbikes, with the pedals seeing next to no use. Mopeds were very popular in the United States during the fuel-crisis of the late 1970s and early 1980s, but their popularity has fallen off sharply since the mid-1980s. In response to rising fuel prices in the first decade of the 2000s, U.S. scooter and moped ridership saw a resurgence. Sales of motorcycles and scooters declined 43.2% in 2009, and continued to decrease in the first quarter of 2010, with scooter sales doing worst, down 13.3% compared to a 4.6% drop for all two-wheelers.
There are various types of off-road motorcycles, also known as dirt bikes, specially designed for off-road events. The term off-road refers to driving surfaces that are not conventionally paved. These are rough surfaces, often created naturally, such as sand, gravel, a river, mud or snow. These types of terrain can sometimes only be travelled on with vehicles designed for off-road driving (such as SUVs, ATVs, snowmobiles and mountain bikes) or vehicles that have off-road equipment. Compared to road-going motorcycles, off-road machines are simpler and lighter, having long suspension travel, high ground clearance, and rugged construction with little bodywork and no fairings for less damage in spills. Wheels (usually 21" front, 18" rear) have knobby tires, often clamped to the rim with a rim lock.
There are specialized motorcycles for a variety of off-road motorcycle sports:
Some motorcycles are specially adapted for specific job functions, such as those used by the ambulance, blood bikes, fire, and military services, and for specialized delivery services, such as pizza deliveries. Beginning in the 1960s with the Mountain Goat specialized motorcycles were developed for use on farms. The Motocrotte (or cainette) was used in Paris to collect dog waste with vacuum suction in the 1980s and 1990s, and was still in use in other French cities as of 2016.
While motorcycles typically have two wheels, some motorized tricycles are classed as three-wheeled motorcycles. Some brands have made various types of three-wheelers direct from the factory. Most of these vehicles are treated as motorcycles for registration or licensing purposes.
Tilting three-wheelers keep all three wheels on the ground when they lean to negotiate curves. These include Honda's Gyro range, all of which have a front wheel that leans and a pair of rear wheels that do not, and the Piaggio MP3, which has two front wheels and a single rear wheel, all of which lean.
sportbike: a motorcycle designed for aggressive performance, especially cornering
Streetfighter -- Also known as a 'hooligan' cycle, this is a sports-bike stripped of all superfluous bodywork.
streetfighter: a type of superbike customized for maximum speed and performance.