Motorcycle Types

Motorcycles come in many different styles, each offering design and performance characteristics to accommodate specific riding conditions. Let's take a look at the common categories of motorcycles.

Street Bikes

Street motorcycles come with all of the necessary equipment to be street-ready. They have lights, mirrors, a horn and a muffler. Their tires have a tread pattern that provides good traction on both wet and dry roads. Street motorcycles generally come in two forms -- touring motorcycles and cruisers. Touring motorcycles are specially designed for long-distance travel. Their most distinctive features are fairings, aerodynamic wind guards that wrap around the headlight to enhance styling and reduce drag. Touring bikes also come with other long-distance amenities, such as saddlebags and a comfortable passenger seat. Cruisers, which typically have no fairings, offer a more laid-back look. They are built with swept-back handlebars, low seats, and casual riding positions with forward-set footpegs.

Sportbikes
Sportbikes are designed to handle well at high speeds and on winding roads. They offer multi-cylinder engines to produce more power, aluminum alloy frames, stiff suspensions to improve handling, high-grip tires and powerful brakes. Instead of sitting up straight, sportbike riders lean forward over the gas tank to reduce wind resistance.

"Naked Bikes"
Naked bikes offer the performance of sportbikes without the aesthetics. In most cases, they are stripped of any unnecessary bodywork. Because they're often the product of bike customizers who want a "road warrior" appearance, naked bikes are also called streetfighters, especially in Europe.

Traditionals

Also known as standards, traditionals look and handle like an archetypical model known as the Universal Japanese Motorcycle (UJM), built primarily in the 1970s. The UJM was an all-purpose, do-everything bike, and today's standards offer the same versatility and straightforward design.

Off-road Bikes
Off-road motorcycles include both motocross bikes and dirt bikes -- machines designed to handle jumps, bumps and other obstacles found on closed racing courses or woodland trails. Off-road motorcycles have narrower, lighter frames, increased ground clearance and advanced suspension systems. They also have a kick-starter to reduce weight and tires with a knobby tread pattern for increased traction. Because off-road bikes usually don't come standard with lights, mirrors, a horn or a muffler, they aren't street-legal.

Dual-purpose
Dual-purpose bikes, also known as dual-sports, are street-legal motorcycles that offer some off-road capabilities. Like dirt bikes, dual-purpose machines are lightweight and durable. Like standards, they offer great versatility for newcomers and long-time riders alike. The dual-purpose motorcycle falls somewhere in between a dirt bike and a street motorcycle. For example, dual-purpose bikes feature specialized tires that work on both dirt and pavement.

Motorcycles of the future to be cleaner and safer through innovation

ACEM, the motorcycle industry in Europe, presented today its strategy to shape the future of motorcycling. On the occasion of its 5th Annual Conference, ACEM outlined an extensive set of measures ensuring that the motorcycles and scooters of tomorrow will be cleaner and safer.

The European motorcycle and moped market has been growing constantly over the last six years, mainly pushed by an increasing powered two-wheeler (PTW – motorcycles and mopeds) mobility demand in European cities. In spite of the looming economic recession, which is expected to also affect the PTW market, ACEM members believe the time is right to commit to new environmental objectives, to maximise the market opportunities and further promoting the PTW with authorities as a mobility alternative, in particular in the urban context.

Over the last decade PTWs already achieved remarkable progress in reducing their environmental impact; ACEM members nevertheless propose to achieve parity of motorcycles with passenger cars Euro 5 reductions in 2015, for pollutant emissions. In the context of upcoming regulatory discussions within DG Enterprise of the European Commission, ACEM’s proposal is to introduce a EURO 3 for mopeds and a Euro 4 stage for motorcycles in 2012, accompanied by a more stringent emission test cycle, and followed by a EURO 5 stage for motorcycles in 2015 with the same emission thresholds as passenger cars. These two steps, necessary to provide sufficient lead time to comply with industrial design and production constraints, are fundamental to contribute to stability and employment in the sector in these difficult times for the economy. Moving from current Euro 3 to Euro 5 will determine a 50% reduction of motorcycle pollutant emissions.

Today ACEM manufacturers also announced a renewed, enhanced commitment to the EU Road Safety Charter related to advanced braking systems. ACEM manufacturers decided to extend their initial commitment of offering 50% of street model PTWs with an advanced braking system by 2010, setting a further objective of 75% by 2015. This joint action on a vast array of advanced braking systems (CBS, F-ABS, R-ABS, ABS, Combined ABS, ABS-PBS, Integral ABS, new vehicle architectures), ensures the large-scale deployment of these safety features on different categories of PTWs, taking into account the specific use of these products, their distinctive characteristics and the cost-effectiveness of the technical solutions. ACEM opposes a legislative approach, which would be detrimental to the variety of systems, potentially freezing innovation.

These were the highlights of the different initiatives announced by ACEM today, seeking to bring further mobility benefits for PTWs: a switch from cars to motorcycles and scooters increases the number of people the urban transport system is able to move, to the benefit of the economy and society. A presentation by Sorbonne University’s Professor Pierre Kopp of a study on PTW mobility in Paris confirmed such economical benefit, highlighting however the important role local authorities have to play to accompany with dedicated policies. Andy Mayo, presenting the eSUM project (www.esum.eu) on behalf of Transport for London pointed in the same direction, outlining promising safety best practices in urban PTW integration.

Stefan Pierer, President of ACEM, reaffirmed the industry’s commitment to innovation and cooperation with the Institutions: “The top priority is to protect businesses and jobs from the worst effects of the current financial crisis. The Recovery Plan proposed last week by the European Commission is a positive signal, which should also apply to the motorcycle industry. We will face over the coming months a delicate period, with challenges for the sector: in October and November, the market significantly reduced compared to last year’s figures. However, I am confident that there will also be opportunities for the industry, in particular in the mid-term if supportive actions are undertaken towards the sector at national and EU level, in support of fleet renewal and development of innovative products.”

Jacques Compagne, Secretary General of ACEM, said: “Enhancing mobility while at the same time reducing congestion, accidents and pollution is a challenge that ACEM manufacturers are willing to undertake working together with EU legislators, city authorities and citizens organisations”.

Motorcycle Chassis

The motorcycle chassis consists of the frame, suspension, wheels and brakes. Each of these components is described briefly below.

Frame
Motorcycles have a frame made of steel, aluminum or an alloy. The frame consists mostly of hollow tubes and serves as a skeleton on w

hich components like the gearbox and engine are mounted. The frame also keeps the wheels in line to maintain the handling of the motorcycle.

Suspension

The frame also serves as a support for the suspension system, a collection of springs and shock absorbers that helps keep the wheels in contact with the road and cushions the rider from bumps and jolts. A swingarm design is th

e most common solution for the rear suspension. On one end, the swingarm holds the axle of the rear wheel. On the other end, it attaches to the frame via the swingarm pivot bolt. A shock absorber extends upward from the swingarm pivot bolt and attaches to the top of the frame, just beneath the seat. The front wheel and axle are mounted on a telescoping fork with internal shock absorbers and internal or external springs.

Wh­eels
­Motorcycle wheels are generally aluminum or steel rims with spokes, although some models introduced since the 1970s offer cast wheels. Cast wheels allow the bikes to use tubeless tires, which, unlike traditional pneumatic tires, don't have an inner tube to hold the compressed air. Instead, the air is held between the rim and the tire, relying on a seal that forms between rim and tire to maintain the internal air pressure.

Tubeless tires are less likely to blow out than a tube-type tire, but on rough roads, they can be a problem because even a small bend in the rim can cause a deflation. Tires come in a variety of designs to match the needs of terrain and driving conditions. Dirt bike tires, for example, have deep, knobby treads for maximum grip on dirt or gravel. Touring bike tires, made of harder rubber, usually provide less grip but last longer. The tires of sportbikes and racers (generally steel-belted radials) deliver astonishing gripping power, especially considering the small area that is in contact with the road surface.

Brakes
The front and rear wheels on a motorcycle each have a brake. The rider activates the front brake with a hand lever on the right grip, the rear brake with the right foot pedal. Drum brakes were common until the 1970s, but most motorcycles today rely on the superior performance of disc brakes. Disc brakes consist of a steel braking disc, which is connected to the wheel and sandwiched between brake pads. When the rider operates one of the brakes, hydraulic pressure, acting through the brake line, causes the brake pads to squeeze against the disc on both sides. Friction causes the disc and the attached wheel to slow down or stop. Brake pads must be replaced periodically because the pad surfaces wear away after repeated use.

Motorcycle Transmission

A motorcycle engine can create an enormous amount of power, which must be delivered to the wheels of the vehicle in a controllable way. The motorcycle transmission delivers power to the rear wheel through a series of structures that include the gearset, the clutch and the drive system.




Gearset

A gearset is a set of gears that enable a rider to move from a complete stop to a cruising speed. Transmissions on motorcycles typically have four to six gears, although small bikes may have as few as two. The gears are engaged by shifting a lever, which moves shifting forks inside the transmission.

Clutch
The job of a clutch is to engage and disengage power from the engine crankshaft to the transmission. Without the clutch, the only way to stop the wheels from turning would be to turn off the engine -- an impractical solution in any kind of motorized vehicle. The clutch is a series of spring-loaded plates that, when pressed together, connect the transmission to the crankshaft. When a rider wants to shift gears, he uses the clutch to disconnect the transmission from the crankshaft. Once the new gear is selected, he uses the clutch to reestablish the connection.







Drive Systems
There are three basic ways to transmit engine power to the rear wheel of a motorcycle: chain, belt or shaft. Chain final-drive systems are by far the most common. In this system, a sprocket mounted to the output shaft (i.e., the shaft in the transmission) is connected to a sprocket attached to the rear wheel of the motorcycle by a metal chain. When the transmission turns the smaller front sprocket, power is transmitted along the chain to the larger rear sprocket, which then turns the rear wheel. This type of system must be lubricated and adjusted, and the chain stretches and the sprockets wear, requiring periodic replacements.

Belt drives are an alternative to chain drives. Early motorcycles often used leather belts, which could be tensioned to give traction using a spring-loaded pulley and hand lever. Leather belts often slipped, especially in wet weather, so they were abandoned for other materials and designs. By the 1980s, advances in materials made belt final-drive systems viable again. Today's belts are made of cogged rubber and operate much the same way as metal chains. Unlike metal chains, they don't require lubrication or cleaning solvents.

Shaft final-drives are sometimes used. This system transmits power to the rear wheel via a drive shaft. Shaft drives are popular because they are convenient and don't require as much maintenance as chain-based systems. However, shaft drives are heavier and sometimes cause unwanted motion, called shaft jacking, in the rear of the motorcycle.

About Engines

Motorcycle engines can have between one and six cylinders. For years, the V-twin design was the engine of choice for motorcycle engineers in America, Europe and Japan. The V-twin gets its name from the fact that the two cylinders form a V shape, such as the classic Harley-Davidson V-twin shown below. Notice the 45-degree angle in the Harley-Davidson V-twin -- other manufacturers may vary this angle to reduce vibration.

The V-twin is just one way to accommodate two cylinders. When the cylinders are oriented so that the pistons oppose each other, the result is an opposed-twin design. Parallel-twin engines have their pistons placed side by side in an upright position.

Today, the most popular design is the four-cylinder, which runs more smoothly and at higher revolutions per minute (rpms) than a comparable twin. The four cylinders can be placed in a row, or they can be arranged in a V-shape configuration, with two cylinders on each side of the V.

Capacity
The size of the combustion chamber in a motorcycle engine is directly related to its power output. The upper limit is about 1500 cubic centimeters (cc), while the lower limit is about 50 cc. The latter engines are usually found on small motorcycles (mopeds) that offer 100-miles-to-the-gallon fuel economy but only reach top speeds of 30 to 35 miles per hour.

Motorcycles Engine

Motorcycle engines work the same way that car engines do. They consist of pistons, a cylinder block and a head, which contains the valve train. The pistons move up and down in the cylinder block, driven by explosions of a fuel-air mixture that has been ignited by a spark. Valves open and close to allow the fuel-air mixture to enter the combustion chamber. As the pistons move up and down, they turn a crankshaft, which transforms the energy from the pistons into rotary motion. The rotational force of the crankshaft is transmitted, via the transmission, to the rear wheel of the motorcycle.
Motorcycle engines are generally classified by one of three characteristics: the number of cylinders they possess, the capacity of their combustion chambers or the number of strokes in their power cycles.

The First Steps to Riding a Motorcycle

• Safety Gear
Motorcycling is a high-risk activity, and the most vulnerable riders are new ones. Protecting yourself with proper safety gear is an easy way to save yourself from injury, but the cost of gear adds up, and you'll want to add this to your biking budget.


• Training Courses
Though it's common practice to experience your first ride in a parking lot, leave motorcycle training to the pros and take a Motorcycle Safety Foundation course. The skills you'll learn will last you a lifetime, and MSF instructors will educate you with fundamental skills that will make you a better, more competent rider.


• Consider Your Bike Options
Will you be borrowing a bike? Are you considering buying your first bike? Plan ahead by either borrowing, renting, or buying a bike, and you'll be more committed to following through with your path to motorcycling. You can also check out our Visual Guide to Motorcycle Types for more information on different bike styles.


• Start Slow
As a newbie, you're most likely to make potentially dangerous mistakes. Relax, take it easy, and learn at your own pace; motorcycling is an acquired skill that takes plenty of practice, and it's important that you keep that in mind while you learn.


• Learn The Rules of the Road
Traffic laws are different for motorcycles, and each state's Department of Motor Vehicles has online manuals for motorcyclists. Download one, and educate yourself on the laws that govern motorcycling.


• Get Licensed
There's no excuse for riding on public roads without a license. Once you've taken a MSF course and learned the basics, schedule an appointment at your local DMV office and take the test.