AMPS: Unit of measurement. Represents the current or flow rate of electricity. Most electric powered scooters will come with a battery system that will show the current in amps, it is usually shown after the voltage as amp hours (Ah).

AUTOMATIC OVERLOAD PROTECTION: A protection added to some engines that will keep the engine from taking too much electricity and burning out.

AXLE: The part of the wheel that holds the wheel to the forks or frame of a scooter. Usually a bolt type device in the center of the hub.

BEARINGS: The part of the wheel that allows the hub to spin freely around the axle without grinding or wearing. Some manufacturers will use sealed bearings which help increase bearing and axle life.

BODY: The secondary structure of the scooter. The body can be made of steel, aluminum, plastic or any combination of those materials and is usually attached to the frame. Some scooter bodies may only consist of a deck while others may include fenders. Plastic bodies are more susceptible to cracking and breaking.

BRAKES (BAND): A band that is tightened around a shaft to stop the rotation of the wheel.

BRAKES (CALIPER): A caliper is a measuring device with two moving parts that come together to determine the dimensions of an object. Most bicycle brakes use a similar mechanism to move the brake shoes inward toward the rim, so they are called caliper brakes.

BRAKES (DISC): A brake in which friction is caused by a set of pads pressing against a rotating disk.

BRAKES (DRUM): A brake in which friction is caused by a set of pads pressing against the inner surface of a rotating drum.

CLUTCH (CENTRIFUGAL): An automatic clutch in which the friction surfaces are engaged by weighted levers acting under centrifugal force at a certain speed of rotation.

CLUTCH (FREEWHEELING): A clutch in the rear-wheel hub that permits the wheel to turn freely without engaging the motor, as in coasting.

DECK: The standing or foot part of the body of the scooter. The deck can be made of steel, aluminum and/or plastic and is usually covered by some type of gripping material. Plastic decks are more susceptible to cracking and breaking.

DRIVE TRAIN: Type of system used to turn the rear wheel.

DRIVE TRAIN (PUSH AND GO): A safety feature added to some scooters that requires the rider to first push the scooter before the power is transferred to the drive train.

FORKS: The forks are the device that holds the front wheel and are controlled (steered) by the stem and handle bars. Forks come in solid and suspended versions. The solid version is similar to a bicycle fork in design, an upside down u shape with slots at each end to attach the wheel. The suspension version will usually use coil spring over shock system in each side or an elastomer spring in each side. Fork suspension systems travel is usually shown in millimeters, 1 inch is equal to 25.4 mm.

FRAME: This is the main structure of the scooter. Most scooter companies construct the frame out of steel. Some frames may be covered with a body made of steel, aluminum, plastic or any combination of the three.

HORSEPOWER (hp): Unit of measurement. You usually see gas powered scooters will show power output as horsepower and not electric scooters, but some electric scooters will offer an hp rating. Visit HowStuffWorks.com for a more thorough definition.

HUB: The inner part of the wheel that holds the spokes, bearings and axle.

IGNITION: The mechanism used to start the engine. Typically a toggle switch or keyed ignition will be available.

MILLIMETERS (mm): Unit of measurement. Most suspension system travel will be shown as millimeters. 25.4 mm is equal to 1 inch.

OFF-BRAND ELECTRIC SCOOTERS AND CLONES: Off-brand electric scooters (aka clones) copy-cat the look of quality brand name electric scooters. They're typically poor in quality, unsupported by the manufacturer or store that sells them and parts are hard to find. Do yourself a big favor and avoid the off-brand scooters and clones!

RANGE: The overall range of the scooter. The overall range will vary with rider weight, riding condition, battery condition and terrain.

RIM: The outside part of a wheel that holds the tire.

SPEED: The top speed that the scooter can reach. The top speed will vary with rider weight, riding condition, battery condition and terrain.

SPOKES: The part of the wheel that holds the rim onto the hub. Spokes can come in a thin steel wire version, thick steel spoke, aluminum spoke, and plastic spoke versions, or in a solid steel, aluminum, or plastic version.

SUSPENSION: Some manufacturers and models come with front and/or rear suspension. This allows the wheel(s) to move up and down absorbing impacts and bumps. The smoother ride will also help increase traction as the wheel(s) stay in better contact with the ground on uneven surfaces. Rear suspension is usually a swing arm set up with a coil spring over shock dampening system. The suspension travel is usually listed as millimeters. 1 inch is equal to 25.4 mm.

THROTTLE: Speed is changed and controlled through the use of a throttle. Most scooters are hand throttle controlled; with either a twist (motorcycle style) or thumb (ATV, Jet Ski style) controller.

TIRE: The rubber part of a wheel attached to the rim. Tires usually have an air filled inner tube inside. Some manufacturers offer solid foam rubber or polyurethane tires. Tires sizes vary from width to height. Tire tread design will also vary.

TIRE (POLYURETHANE): A very durable rubber/plastic compound used to make wheels for a variety of products including scooters. Usually found on small push scooters and small electric scooters.

TIRE (PNEUMATIC): An air filled tire.

TORQUE: The turning or twisting "rotational force" force exerted at the crankshaft by the motor.

TRANSMISSION: The system that transfers the motors power to the drive train.

VOLTS (v): Unit of measurement that represents the power or force of electricity available.

WATTS (w): Unit of measurement that represents the power output of an electric engine. 746 watts is equal to 1 horsepower.

WHEEL: The entire part that includes the axle, hub, spokes and rim. Wheels come with wire spokes, solid spoke or a spoke less solid design. Wheels come in steel, aluminum and reinforced plastic. Smaller scooters may have solid polyurethane wheels with sealed bearings and an axle. This type of wheel is more common on push scooters.