Ah

Abbreviation for "amp-hour", which is a unit of electric charge that can be delivered by a battery.

Allen bit

A bit with a hexagonal head. The Allen bit must be attached to a wrench, ratcheting wrench, torque wrench, or other similar device.

alternating current

A fundamental concept of electricity that describes the movement or flow of an electric charge. Alternating current (AC) changes direction and voltage polarity, and is the power supplied by household outlets/power plants. See also "direct current."

amp

Short for “Ampere,” a base unit of electric current.

amp-hour

Abbreviation for "ampere-hour," which is a unit of electric charge that can be delivered by a battery.

ampere

Base unit of electric current.

axle

The component at the center of the hub that connects the wheel to the dropouts of the bike frame.

axle spacer

A piece of hardware that slides onto an axle to create space between components.

backlight

Illumination from behind or the source of that illumination. Example: the LCD displays on many of the bikes from Rad Power Bikes are backlit. Not to be confused with "taillight," the light on the back of a vehicle.

barrel adjuster

A component on each brake lever and caliper that can be used to adjust brake cable tension.

bashguard

A sturdy component that protects a more sensitive part (like a derailleur) from impacts.

battery

An energy storage device with components that deliver a specific voltage and current capable of powering an electric motor.

battery capacity gauge

An indicator on the LCD display that shows an estimate of how much charge the battery has at that moment.

battery level indicator light

An indicator on the LED display that shows an estimate of how much charge the battery has at that time.

battery management system

An electronic circuit that protects the battery for safe operation.

battery mount

A mount on the frame that supports the battery and allows the battery to connect to the bike's electrical system.

battery receptacle

The connector located at the end of the battery mount.

bearing

A steel ball used to reduce friction between moving parts.

bottom bracket

A part of the bike frame that's located near the cranks and that contains components that allow the cranks to rotate.

bottom bracket spindle

The rotating axle inside the bottom bracket that allows the cranks to turn.

brake

A device for slowing or stopping a moving vehicle. On bikes by Rad Power Bikes, the brakes are mechanical disc brakes that use a metal disc rotor near the hub that is squeezed by ceramic brake pads and a caliper when the brake levers are depressed.

brake cable

A cable connecting each brake lever to a brake caliper.

brake caliper

One of two "jaws" located at each wheel. When a brake lever is depressed, the caliper squeezes the brake pads against the brake rotor to slow or stop the wheel.

brake lever

A lever component (on each side of the handlebar) that the rider squeezes to slow the bike.

brake lever sensor

A sensor inside the brake lever that sends a signal to the controller to cut off motor power when the lever is squeezed. See also "motor cutoff."

brake lever sensor cable

A cable that carries an electrical signal from the brake lever sensor to the controller when a brake lever is squeezed, cutting off power to the motor.

brake light

A light on the back of a vehicle that illuminates when brakes are engaged. See also "taillight."

brake pad

The components inside each brake caliper that make contact with the brake rotor when a brake lever is squeezed, causing friction that slows the bike.

brake rotor

A metal disc attached to the wheel hub that rotates between the brake pads. When a brake lever is squeezed, the brake pads clamp onto the brake rotor, causing friction that slows the bike.

brushless motor

A motor type that is more mechanically simple than motors with brushes.

cable cover

A removable cover that keeps cables tidy and protected. Not to be confused with cable housing.

cable crimp

Piece of hardware that is secured, via crimping, over the end of a metal cable to prevent fraying. Sometimes called a ferrule or swage.

cable guide

A structure on a bike or an item added to a bike. Used to secure a cable (e.g., brake cable).

cable housing

The weather-resistant external tube that holds and protects a cable (e.g., brake cable). Sometimes called the "conduit" or "cable conduit."

cable pinch bolt

A bolt and washer that, when tightened, secure a cable in position.

cadence

The rate at which the bike is being pedaled.

caliper

Non-bike-specific term for one of two "jaws" that comprise a device either for a measuring or for pressing frictional material against the sides of a rotating wheel or disc. Usually used in the plural (calipers) to refer to the entire device. See also "rim brake," "disc brake," and "hydraulic brake."

caliper adapter

A specialized piece of hardware that allows a brake caliper to be mounted to a particular bike frame.

captive flat washer

Flat washer that is pre-installed on a fastener (e.g., bolt) and cannot be removed.

captive split washer

Split washer that is pre-installed on a fastener (e.g., bolt) and cannot be removed.

captive washer

A washer that has been “pre-loaded” onto the shaft of a screw or bolt during manufacturing and cannot be removed.

cassette

The sprockets (stacked set of gears or cogs) on the rear wheel. When a rider shifts gears, the derailleur moves the chain to another cog on the cassette. See also "freewheel."

castle axle nut

A type of nut secured with a cotter pin.

chain

Linked metal pieces. On a bike, the chain is a loop that transfers power from the pedals/front chainring to the rear wheel.

chain tensioner

A device that applies force to the chain to maintain correct tension.

chainlink

A single metal component that is part of a chain.

chainring

The circular metal disc near the crank arm that grabs the chain links as a rider pedals.

chainstay

The part of the frame that runs parallel to the chain.

chainstay brace

Part of the bike frame that provides extra stability to the chainstays by connecting the two chainstay sides near the rear wheel. Also called a "chainstay bridge."

charger

A device for charging batteries.

charging port

A receptacle on the battery to plug in the charger to charge the battery.

chassis

The base frame of a motor vehicle.

clamp bolt

A type of bolt used to secure a part in place by forcing it against an immovable part.

commuter bike

A bike used for commuting in an urban area.

cone spring

A spring shaped like a cone, with one wide and one narrow end.

connector

A component created by plugging in two matching cable ends.

connector terminal

The metal pins inside a connector.

controller

A large, black rectangular component that acts as the "brain" of the bike. The controller allows electrical components to communicate and controls the motor.

cotter pin

A pin that goes through a castle nut to provide security against loosening by vibration. See also "castle axle nut."

crank

One of two metal arms that connect each pedal to the chainring/bottom bracket to move the bike forward when pedaling.

crank arm

One of two metal arms that connect each pedal to the chainring/bottom bracket to move the bike forward when pedaling.

crankset

A rotating part of a drivetrain consisting of the front chainring, cranks, and pedals. The crankset allows the bike to move forward when a rider is pedaling.

crossbar

The horizontal bar that joins and stabilizes the two sides of BMX-style and some cruiser handlebars.

crowfoot bit

Special type of bit used with socket wrench or torque wrench. Shaped like an open-ended pedal wrench. Can be used to torque a pedal to a specific torque value.

current

A fundamental concept of electricity that describes the movement or flow of an electric charge. Direct current (DC) flows in one direction with a constant voltage, and is the current delivered by an AA battery, for example. Alternating current (AC) changes direction and voltage polarity, and is the power supplied by household outlets/power plants.

deflopilator

A spring that connects the front fork of a bicycle to the frame to keep the wheel from "flopping" when parked on the kickstand, helping to keep the bike stable.

derailleur

The mechanism that moves the chain from cog to cog.

derailleur bashguard

A protruding metal bracket that protects the derailleur from impacts.

derailleur limit screw

One of two adjustable screws that change the derailleur's range of motion.

direct current

A fundamental concept of electricity that describes the movement or flow of an electric charge. Direct current (DC) flows in one direction with a constant voltage, and is the current delivered by an AA battery, for example. See also "alternating current."

direct drive motor

A type of motor that has no gear reduction. It is more efficient at higher speeds, slightly slower when starting, and slightly quieter when riding. See also "gear reduction" and "geared motor."

disc brake

Type of braking system that uses calipers to squeeze brake pads around the sides of a brake rotor to slow the bike. See also "rim brake" and "hydraulic brake."

downtube

The part of a bike frame that connects the headtube to the bottom bracket.

drive side

The side of the bike that includes certain parts of the drivetrain including the chain and the derailleur or chain tensioner.

drivetrain

A system of parts that delivers power to the axle. On a bike, this can include the chain, freewheel, derailleur, etc.

dropout

Part of the frame at the front fork and back of a bike frame that is designed to hold the wheel axle.

ebike

Short for "electric bicycle"—a bicycle that can use electricity, stored in a battery, to propel the bicycle.

extreme riding

Riding techniques and stunts that include but are not limited to jumps, wheelies, or any riding that exceeds your capabilities or the strength of specific bike parts or joints. Extreme riding can result in bike damage and/or personal injury or death.

faceplate

A plate that protects a piece of machinery or electronics. Frequently used for the front-facing component that wraps about halfway around the handlebar and fastens to the stem in order to secure the handlebar. See also "stem faceplate."

fender

A semicircle of plastic or metal that, when installed, is positioned over the wheel of a bike and blocks water, mud, and other debris from spraying up from the tires onto a rider and cargo.

fender mounting arm

A lengthy piece of hardware that helps attach and align a fender correctly to the frame/rear wheel or fork /front wheel.

flash mode

A mode that involves flashing. Some bikes from Rad Power Bikes include a button on the backlight that causes it to flash continuously, which can improve visibility of the bike.

flat

A flat tire/tube. See also "pinch flat" and "puncture flat."

flat washer

A flat, round piece of hardware with a hole in the middle. Used on a bolt or screw to distribute clamping force over a larger area.

flat-side cutters

A tool similar in shape to pliers, with a flat, cutting edge used to snip zip-tie excess flush against the zip tie locking mechanism.

folding handlebar stem

A handlebar stem that folds. The RadMini and RadMini Step-Thru models include a handlebar stem riser that folds, though this feature is generally called a "folding stem" for simplicity.

folding stem

A handlebar stem that folds. The RadMini and RadMini Step-Thru models include a handlebar stem riser that folds, though this feature is generally called a "folding stem" for simplicity.

fork

The front portion of the bike frame to which the front wheel is attached.

fork arch

On bikes with built-in suspension, the fork arch connects the top of the two fork lowers. See also "fork" and "fork crown."

fork crown

The top part of the fork where the two fork lowers join each other and merge into the steerer tube. See also "fork arch" and "fork."

fork dropout

One of two dropouts on each fork lower that hold the wheel axle.

frame

The metal tubing that connects all of the bike components and supports the weight of the rider.

frame hinge

The hinge that is part of the folding mechanism on the frame of a folding bike (e.g., the RadMini). See also "folding handlebar stem."

frame stand

A small, triangle-shaped metal part below the bottom bracket. It protects the crank in certain situations, such as when a RadMini is folded and stored away.

freewheel

A mechanism that threads onto the hub and allows the gear/sprocket to be propelled when a rider pedals forward, but also allows the rear wheel to continue to rotate when a rider stops pedaling or pedals backward. See also "cassette."

front rack

Rigid structure on the front of a bike (either built-in or added as an accessory) that is designed to support cargo.

gear

A metal disc with teeth that grab and revolve the chain.

gear reduction

A motor feature in which a smaller gear (a "reduced" gear) with fewer teeth drives a larger gear with more teeth. This reduces the rotary speed of the output, but increases torque.

geared hub motor

A geared motor located on the hub. See also "geared motor," "gear reduction," and "hub motor."

geared motor

A type of motor that uses gear reduction. Bikes with this type of motor have more low-end torque, start slightly more quickly and more efficiently, and are slightly louder than a direct-drive motor. See also "gear reduction" and "direct drive motor."

grommet

A flexible ring or loop that strengthens or protects an opening.

handlebar

The bar that the rider holds onto and uses to steer the front wheel and bike.

handlebar grip

A part of the handlebar, one on each end, designed for the hand to grip.

handlebar stem

The vertical tube that connects the handlebar to the steering column.

headlight

Light on the front of a bike or other vehicle. Used to increase visibility of the bike and also illuminate the path of the vehicle.

headset

A system inside the headtube of the bike that uses ball bearings to allow the fork steering column and front wheel to rotate and turn.

headtube

The part of the bike frame that connects the front fork and the handlebar.

headwind

Wind blowing in the opposite direction of a traveler.

helmet

Protective head covering. A bike helmet should always be worn while riding a bike. Different countries/regions have different laws regulating what can be sold as a bike helmet.

hinge pin

A small metal cylinder that a hinge rotates around.

hub

The hollow cylinder in the middle of a wheel.

hub motor

A motor located at the center of a wheel. Contrast with "mid-drive motor."

hydraulic brake

A brake system in which hydraulic fluid, not a mechanical cable, is used to transmit the brake force from the brake lever to the caliper to slow the bike.

ignition

Act of igniting. Used to describe the start-up process for internal-combustion engines like those in most cars. Not an accurate term for any start-up component in an electric vehicle such as an ebike. See also "keyport."

insertion point

In the context of bicycles, "insertion point" refers to how far one component is inserted into another component (e.g., how far the seatpost is inserted into the seat tube). If there is a limit to how far an inserted post can be safely withdrawn from another component, such posts will be marked with a "minimum insertion point." The "minimum insertion point" should never be visible once the post has been positioned and secured.

jockey wheel

The two pulleys near the rear wheel that take up slack from the bike chain, creating an S-shape in the chain next to the derailleur.

keyport

The area on the battery where you insert a key.

kickstand

A swiveling metal bar or bars that can be used to prop up a bicycle when it is not in use.

LCD display

The display on most models that shows various bike and trip details.

LCD display remote

The remote on the left side of the handlebar that allows the rider to interact with the LCD Display and related functions (e.g., adjust pedal assist level or turn on the headlight).

lead acid battery

An older, heavier battery technology used in early model electric vehicles (not used in any bikes by Rad Power Bikes).

LED

An acronym for "light-emitting diode." Rad Power Bikes uses this technology in the taillight, headlight, and LED display. See also "LED display."

LED display

A display on some models that shows various bike details. See also "LED."

lithium-ion battery

An advanced, rechargeable battery technology that has a high energy density (a lot of capacity in a compact battery), no memory effect (the battery won't be damaged with frequent use/charging), and low self-discharge (the battery will maintain its charge when not in use).

lock mount

Mount for a lock.

locking pin

Pin used in a locking mechanism.

locknut

A nut specifically designed to resist loosening by vibration.

lockout lever

Available on some front suspension forks. The lockout lever can "lock" the fork so that it does not absorb shocks. This can make pedaling more efficient but can make your ride feel bumpier.

lockring

A notched, circular component that's reverse-threaded to prevent the brake barrel adjusters or another component from coming loose.

mechanical brake

A brake system in which braking force is transmitted by a cable mechanism.

mechanical disc brake

A disc brake system in which braking force is transmitted by a cable mechanism.

metal mounting tab

Tab, made of metal, configured to facilitate mounting. Similar to a small bracket.

mid-drive motor

A motor located at the center of a bike, typically between the pedals. Compare to "hub motor."

mid-step

Bike frame with a top tube that is fairly low or that angles down from the headtube toward the middle of the seat tube. Easier to mount than a high-step frame, especially for those who are shorter than average, as it provides a lower standover height than a high-step. Compare to "high-step" and "step-through."

moped

A low-powered motorcycle that can have pedals; considered a motorized vehicle requiring a license, insurance, and other requirements depending on local laws.

motor cutoff

A feature that cuts off all power to the motor when a brake lever is squeezed.

motor drive assembly

General term for the motor and components (hardware, electrical) that connect the motor to the bike and its electrical system.

motor hall fault

A type of error that has to do with wires in the motor or the motor's communication with other bike components.

mounting arm

A lengthy piece of hardware that attaches one part to another part or stabilizes the position of a component. See also "fender mounting arm."

mounting bolt

A bolt used to mount one component to another.

mounting window

A window-like opening designed for mounting something. For instance, many of the rear racks for Rad Power Bikes contain a mounting window compatible with the Thule Yepp Maxi child carrier.

needle nose pliers

Type of pliers that has long, tapering jaws with pointed tips, often used for gripping small items.

odometer

An instrument that measures distance traveled. Models with an LCD display have an odometer readout showing total distance traveled by that bike. Compare to "trip odometer."

ohm

Unit of electrical resistance.

pannier

A bag that can be mounted on a rear rack to carry cargo.

PAS

Short for "pedal assist system," a system that, when selected at the display, deploys power to the motor based on the rider’s pedaling.

payload

The weight carried by a product, not including the weight of the product itself.

payload capacity

The maximum recommended amount of weight that a product can safely support (not including the weight of the product itself). Payload capacity on a bicycle can vary depending on how weight is distributed. See your bike manual for more specific information.

pedal

The component that a rider presses their feet against and rotates to propel the bike.

pedal assist

A system that speaks to the motor to provide power based on the rider’s pedaling.

pedal assist sensor

The electronic device used to detect a rider's pedaling. See also "pedal assist."

pedal wrench

An open-ended wrench used to tighten pedals. Thinner than standard wrenches to fit into the narrow space between pedal and crank. See also "crowfoot bit."

Phillips head screwdriver

A screwdriver with an "x" head.

pinch flat

A type of flat caused by the tube being pinched between the rim of the wheel and a hard riding surface. This is more likely to occur when tires are inflated below the recommended tire pressure. When changing this type of flat, the damaged area of the tube may look like one or two parallel lines.

pneumatic support

Type of spring or damper that uses air pressure to provide support.

pneumatic tire

A type of tire that holds air and should be inflated to the pressure listed on the tire sidewall.

power

The rate energy is transferred/transformed over time; measured in watts.

power button

Button that turns the power on or off.

preload adjustment knob

On some bikes with a front suspension fork, the preload adjustment knob is a device that allows you to adjust the resistance of the suspension fork from softer to tighter. See "lockout lever" and your owner's manual for more information.

programming cable

A cable/dongle near the bottom bracket used to program the controller during manufacturing.

puncture flat

A type of flat caused by a sharp object stabbing the tire and tube. Typical causes are thorns, thistles, sharp rocks, broken glass, tacks, and other sharp objects. Tire liners can help decrease the likelihood of puncture flats happening, but cannot prevent them in all situations.

quick release

A lever that enables adjustment or removal of parts, like the seatpost and front wheel, without tools.

quick release skewer

A lever and metal rod that is installed in the front wheel hub and allows for removal of the front wheel without tools.

rack

A rigid structure on a bicycle used for supporting cargo and, in some cases, passengers.

ratcheting wrench

A type of wrench that ratchets, making it possible to tighten or loosen a fastener without having to reposition the wrench repeatedly.

rear rack

A bicycle rack located at the back of the bicycle, above the rear wheel. Used for supporting cargo and, in some cases, passengers.

reflector

A component that light bounces off of and back to the source of light. Used on bikes to increase the bike's visibility, should be attached and visible at all times, and may be required by law.

regenerative braking

A method for converting part of the braking energy into a small amount of battery capacity.

repair stand

A device designed to secure a bike, most commonly off the ground, for maintenance activities.

resistance or rolling resistance

The drag or force resisting the movement of a wheel across a surface. All wheels will eventually slow down due to resistance of moving parts against each other.

rim

The metal ring that holds the tire and is connected to the hub by spokes under tension.

rim brake

A type of brake system that uses calipers to press frictional material against the bike rim in order to slow down wheel rotation. Not used in any bikes from Rad Power Bikes. Compare to "disc brake."

rim strip

A strip of material on the inside of the rim that protects the inner tube from being punctured by the spoke holes.

roll pin

A pin-shaped component that rolls.

Schrader valve

A common type of pneumatic tire valve.

seat

The component on a bike that holds the majority of a rider’s weight.

seat adjustment bolt

A bolt under the seat that, once loosened, allows the seat to be adjusted.

seat mounting bolt

A bolt that secures the seat to a custom mount.

seat tube

The part of the frame that the seatpost slides into.

seatpost

The long metal tube that connects the seat to the seat tube.

seatstay

A part of the frame which connects seat tube to the rear dropout.

seatstay brace

Part of the bike frame where the two sides of the seatstay join, usually in an arch, just above the rear wheel.

self-adhesive

Describes an object that is manufactured with a strip of adhesive (usually covered by a strip of material that can be easily removed when it's time to adhere the object to another surface).

set screw

A small screw used for making adjustments to parts including brake calipers and brake levers.

shank (bolt shank)

The shank of a fastener (screw or bolt) is the entire fastener minus the head.

shift gear

To transition from one gear to another. See "gears."

shift lever

A lever at the handlebar that is used to shift gears.

single-speed bike

A bike that has only one gear.

skid plate

A flat plate designed to skid along another surface. On a bike, a skid plate may be installed underneath sensitive components to protect them from accidental exposure to riding terrain (bumps, rocks, etc.).

split washer

A washer that is split on one side, with the two edges offset. Also called a "lock washer."

spoke

One of many metal rods that connect the rim to the hub of a bike wheel.

steerer tube

The upper part of the front fork that goes into the headtube and attaches to the turning parts of the headset and handlebar stem to allow steering.

stem

The vertical tube that connects the handlebar to the steerer tube inside the headtube.

stem angle

The angle of the stem relative to the headtube.

stem clamp bolts

Bolts that secure the stem to the steerer tube on most bikes. In the case of a bike with a stem riser, the stem clamp bolts attach the stem to the stem riser.

stem faceplate

A plate used to secure the handlebar to the handlebar stem. See also "faceplate."

stem folding mechanism

The entire folding mechanism on a folding handlebar stem riser.

stem riser

Component that connects the steerer tube to the stem. Not present in all bike designs.

stem riser clamp bolts

Bolts that secure the stem riser to the steerer tube.

step-through

A frame design that allows a rider to mount the bike with a low step in front of the seat rather than swinging a leg over the seat/ back of the bike.

strip

To damage a bolt or screw head by letting the tip of the driver slip out of the head while turning, expanding the opening that the driver must fit into snuggly. Mostly commonly happens when the driver is not fully inserted into the bolt head, not enough force is exerted toward the bolt to maintain a secure fit, turning is attempted too rapidly, or the wrong tool or tool size is used. Stripping a bolt head can make it difficult or impossible to loosen or tighten the bolt afterward, and special tools may be needed to extract the damaged bolt.

stripped bolt head

A bolt head whose drive slot(s) have been damaged by a driver slipping out of the slot and distorting the slot shape such that it can no longer be easily turned by the driver.

suspension fork

A front fork with built-in shock absorption. See also "front fork" and your owner's manual.

suspension seatpost

A seatpost with built-in shock absorption.

taillight

A light, located on the back of a vehicle, that increases the vehicle's visibility.

telescoping seatpost

A seatpost that comes in more than one section, one of which can slide into the other section. Provides a greater range of height adjustment.

terminal contact

One of several contact points through which power from a battery passes to the device that uses battery power.

thread

To turn a threaded object (e.g., a screw or bolt) into another material or a threaded mount.

threaded

Having threads (spiral grooves used for fastening)

threadlocker

Liquid applied to fastener threads to increase their resistance to loosening via vibration.

threads

The spiral grooves on a fastener (like a screw or bolt).

thumb nut

A type of nut designed to be easy to grip (i.e., with your thumb/fingers).

tire

The round rubber/fiber casing for the inner tube that connects to the rim and that the wheels roll on.

tire bead

A ridge molded on the edge of the tire that keeps the tire attached to the rim when the tube is inflated.

tire sidewall

The side of a tire, which provides lateral stability and helps protect the layers of the tire as well as the pneumatic inner tube.

top cap

Cap that conceals and protects the top-cap bolt, which attaches the handlebar stem to the steerer tube.

top cap bolt

Bolt that attaches the handlebar stem to the headset/steerer tube inside of the headtube. Called the "top cap" bolt because it passes through the top cap, which is what seals off the headtube and its contents from the elements.

top cap bolt cover

Small cover (usually in the form of a flexible plug) that covers and protects the head of the top cap bolt, which would otherwise be exposed in the center of the top cap.

top tube

The portion of the bike frame that connects the headtube with the seat tube. On a typical step-through frame, instead of a top tube, there is an extra robust downtube.

torque

A rotational force. Used to describe tightening a component or hardware to a specific value.

torque

To apply rotational force.

torque arm

A piece of hardware that resists the twisting forces of a hub motor when applying power to the motor. See also "torque washer."

torque value

A specific amount of rotational force, typically measured in "Newton meters" (Nm).

torque washer

A type of asymmetrical washer with a protruding tab that helps resist the torque force between the axle and the frame. See also "torque arm."

torque wrench

A tool used to apply a specific torque (rotational force) to a fastener such as a nut or bolt.

tread

The part of the tire designed to come into contact with the road (or other surface).

trike

A vehicle with three wheels.

trip odometer

A feature that measures how far a vehicle has traveled during a specific interval.

true

Describes a spinning component, such as a wheel, that spins straight, without any wobble. See also "truing" and "untrue."

truing

The process of adjusting a spinning component (such as a wheel or disc rotor) so that it spins straight, without any wobble. See also "true" and "untrue."

tube

Inflatable, usually ring-shaped rubber component that holds air inside the tire. Sometimes called "inner tube."

twist power assist

A part at the handlebar that allows the rider to manually call up additional power from the motor and battery while pedaling. 

Universal Serial Bus

A connector standard for many computers, mobile phones, and other electronics.

untrue

A component that wobbles when spinning. See also "true" and "truing."

volt

Abbreviated "V." The unit of electrical potential energy, or the difference of potential that would drive one amp of current against one ohm of resistance.

voltage

A fundamental concept of electricity that describes electric potential difference.

walk mode

A feature that allows the rider to walk beside the bike and push the bike forward with help from the motor. See your manual for more information.

washer

Flat, circular disk with a hole in the center, placed on a bolt or screw shaft to distribute clamping force of the fastener over a larger surface area.

watt

A measurement of power.

watt hour

A measurement of energy used to describe battery capacity.

watt meter

An instrument for measuring electric power.

wheel

The portion of a bike that includes the rim, spokes, and hub. May also include the motor assembly, cassette or freewheel, tube, and tire.

wheel skirt

A shield that can be installed on the sides of a wheel to protect it (or a passenger) from damage or injury.

wingnut

A nut designed to be tightened by hand (without tools).

wiring harness

An assembly of electrical cables bound by durable material (cable housing) to optimize space and make assembly and maintenance easier.

wiring harness connector

The large connector, usually located near the controller or inside the downtube, that connects the wiring harness to the controller.