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 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.
Street
Road motorcycles are motorcycles designed for being ridden on paved roads. They feature 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).
Cruiser
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. They are often custom projects that result in a bike modified to suit the owner's ideals, and, as such, are a source of pride and accomplishment. Cruisers are sometimes called custom even in the absence of aftermarket modifications (see Custom (motorcycle)). Power cruiser is a name used to distinguish bikes in the cruiser class that have significantly more engine output, around 80–100 hp (60–75 kW) as opposed to about 50–70 hp (37–52 kW). They often come with upgraded brakes and suspensions, better ground clearance, and premium surface finishes, as well as more exotic or non-traditional styling
Touring
Although any motorcycle can be equipped and used for touring, touring motorcycles are meant 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. Large touring bikes are sometimes called dressers, especially those that are based on a cruiser platform. 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.[
Sport Touring
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 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, is listed by Honda as a sport touring motorcycle in the USA and Australia, but as a touring motorcycle in Europe.
Standard
Standards are versatile, general purpose street motorcycles. They are recognized primarily by their upright riding position, partway between the reclining posture of the cruisers and the forward leaning sport bikes. Foot pegs are below the rider and handlebars are high enough to not force the rider to reach far forward, placing the shoulders above the hips in a natural position. Standards are often recommended to beginning motorcyclists due to their flexibility, relatively low cost, and moderate engines.
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 (UJM), 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