E-Bike Glossary

Legal classes and law

Speed, Power and Pedals Set the Legal Class

Each country draws its own line between a bicycle and a motor vehicle. State-by-state and country rules are on the laws pages.

E-bike (electric bicycle)

A bicycle with working pedals and an electric motor that stays within a legal limit on power and assisted speed. A two-wheeler that exceeds the limit is a moped or motorcycle in law, whatever it looks like.

Low-speed electric bicycle (15 U.S.C. 2085)

The US federal definition, added to the Consumer Product Safety Act in 2002: a two- or three-wheeled vehicle with fully operable pedals and a motor under 750 W (1 hp) whose top speed on motor power alone, with a 170 lb rider on level sidewalk, is under 20 mph. It makes the e-bike a consumer product under the CPSC and leaves road use to the states.

Class 1

A US state e-bike class: pedal assist only, motor under 750 W, assistance stops at 20 mph. Most states allow Class 1 bikes wherever ordinary bicycles may ride.

Class 2

A US state e-bike class with a throttle that can drive the bike without pedaling, motor under 750 W, motor cutoff at 20 mph. Many Class 2 bikes also have pedal assist to 20 mph.

Class 3

A US state e-bike class: pedal assist only, motor under 750 W, assistance stops at 28 mph, and a speedometer is required in most states. States set a minimum rider age, usually 15 or 16, and some keep Class 3 bikes off multi-use paths.

"Class 4"

A sales label for electric two-wheelers above 750 W or 28 mph; no US state or federal law defines a Class 4 e-bike. On a public road such a vehicle is an unregistered moped or motorcycle. Class 4 e-bikes covers the label in detail.

Class label

A permanent sticker that three-class states require on each e-bike, showing its class, top assisted speed and motor wattage. A rider who modifies the motor must update it.

EPAC

Electrically power assisted cycle, the term used in European standards such as EN 15194 and EN 17404. An EPAC assists only while the rider pedals, cuts out at 25 km/h and has a motor rated at 250 W continuous or less.

Pedelec

Pedal electric cycle, the everyday European name for an EPAC: 250 W, assist only while pedaling, cutoff at 25 km/h. EU Regulation 168/2013 excludes pedelecs from motor-vehicle rules, so they ride as bicycles with no license, plate or insurance.

S-pedelec

A speed pedelec that assists to 45 km/h, which places it in EU moped class L1e-B. It needs type approval, an insurance plate, a helmet and an AM license, and in Germany it stays off bike paths unless a sign allows it (Germany e-bike laws).

L-category vehicle

The EU class of two-, three- and four-wheel motor vehicles under Regulation (EU) 168/2013, from L1e mopeds through L3e motorcycles to L7e heavy quadricycles. Every L-category vehicle needs EU type approval before sale.

L1e-A

The EU powered-cycle class: pedal cycles with motor assistance to 25 km/h and up to 1 kW continuous. Throttle-only bikes and 25 km/h bikes with motors above 250 W land here, and each country decides the license and plate rules.

L1e-B

The EU moped class: two-wheelers with a design speed up to 45 km/h and up to 4 kW continuous. S-pedelecs and most seated electric scooters sold in Europe are L1e-B.

L3e

The EU motorcycle class for two-wheelers faster than 45 km/h or above 4 kW. Electric motorcycles from Zero, Energica and CFMoto, and road-legal versions of Sur-Ron and Talaria e-motos, are L3e.

AM license

The EU driving license category for mopeds, including L1e-B S-pedelecs and seated scooters. Germany issues it from age 15, and a class B car license includes it.

eKFV

Germany's Elektrokleinstfahrzeuge-Verordnung (Small Electric Vehicles Ordinance) of 2019, which admits stand-up e-scooters with a handlebar, 6 to 20 km/h, with an insurance sticker and riders 14 and older. A 2026 amendment moves its riding rules into the StVO road code from March 1, 2027 and requires turn signals on new scooters (Germany e-bike laws).

EAPC

Electrically assisted pedal cycle, the UK legal term under the Electrically Assisted Pedal Cycles Regulations: motor up to 250 W, assistance cut at 15.5 mph (25 km/h), rider 14 or older. The UK government consulted on raising the limit to 500 W and allowing throttles, then dropped the proposal.

GB 17761

China's mandatory national safety standard for electric bicycles. The 2024 edition, GB 17761-2024, took effect September 1, 2025: power cuts out above 25 km/h, plastic parts may make up no more than 5.5% of the vehicle, and lead-acid models may weigh up to 63 kg; noncompliant bikes could not be sold after December 1, 2025.

Moped

A low-power motor vehicle. In the EU it is class L1e-B, up to 45 km/h; in the US each state defines it, often as a two- or three-wheeler limited to 30 mph and about 2 hp, with registration, a plate and a license.

Motor-driven cycle

A US term for a small motorcycle. Federal motor vehicle safety standards (49 CFR 571.3) define it as a motorcycle of 5 hp or less, and states such as California use it for motorcycles of 149 cc or less, with their own license and equipment rules.

E-moto

An electric motorcycle or electric dirt bike, such as the Sur-Ron Light Bee or Talaria Sting, with no working pedals or with motors and speeds far above e-bike limits. Most are sold for off-road use in the US and need registration as motorcycles to ride on public roads.

Drive systems

A Drive Is a Motor, a Sensor and a Controller

Motor makers, torque figures and sensing are compared on the drive systems page.

Hub motor

A motor built into the front or rear wheel hub that drives the wheel directly at one fixed ratio, whatever gear the rider selects. Bafang, the largest Chinese drive maker, and Mahle with its X20 rear hub supply them.

Geared hub

A hub motor with a planetary gear reduction inside, so a small, fast motor turns the wheel slowly. It is lighter and freewheels with little drag when the motor is off.

Direct-drive hub

A gearless hub motor in which the motor's magnets turn with the wheel. It is heavier and adds drag when unpowered, but it is quiet and can recover some energy under braking.

Mid-drive

A motor at the bottom bracket that drives the chainring, so its output passes through the bike's gears. The Bosch Performance Line CX, Shimano EP801, Yamaha PW-X3 and DJI Avinox are mid-drives.

Torque sensor

A sensor, usually strain gauges on the crank spindle, that measures how hard the rider pushes on the pedals. The controller adds assistance in proportion, which is standard on mid-drives from Bosch, Shimano, Yamaha and DJI.

Cadence sensor

A magnet-ring sensor that detects only that the cranks are turning and switches the motor on at a set level, whatever the rider's effort. It is cheaper and common on hub-motor bikes and conversion kits such as the Bafang BBSHD.

Nm (newton-meters)

The unit of motor torque, the turning force that decides how hard a drive pulls on climbs. Flagship mid-drives run from 50 Nm on the TQ HPR50 to 150 Nm on the DJI Avinox M2S; hub-motor torque is measured at the wheel and does not compare directly.

Nominal vs peak watts

Nominal (rated continuous) power is the output a motor can hold indefinitely; peak power is a short burst. The EU 250 W limit refers to rated continuous power, so the Bosch Performance Line CX is a 250 W motor that peaks at 750 W.

Controller

The electronics that read the sensors and the rider's assist setting and meter battery current to the motor. It also enforces the assistance cutoff at the legal speed.

Display / HMI

The human-machine interface: the handlebar display and buttons that show speed, battery level and assist mode and let the rider change them. Bosch Kiox and Purion and the Shimano EN600 are examples, and many systems now pair with a phone app.

Assist level

A selectable mode, such as Bosch's Eco, Tour+, eMTB and Turbo, that sets how much the motor adds to the rider's effort. Higher levels draw more from the battery.

Throttle

A twist grip or thumb lever that runs the motor without pedaling. In the US it makes a bike Class 2; in the EU a throttle above walking speed moves the bike out of the pedelec class into L1e-A or L1e-B.

Walk assist

A button-held mode that moves the bike at walking pace while the rider pushes it, useful on ramps and with loaded cargo bikes. The EU pedelec rules allow it up to 6 km/h without pedaling.

Batteries and charging

Watt-Hours Measure a Pack, Cells and Chemistry Decide Its Safety

Pack layouts, cell makers and chemistries are on the batteries page.

Wh (watt-hour)

The unit of battery energy: nominal voltage times amp-hours. Energy sets range, and e-bike packs commonly hold 400 to 800 Wh, such as the Bosch PowerTube line.

Ah (amp-hour)

The unit of battery charge capacity, the current a pack can deliver for one hour. Ah alone does not compare packs of different voltages; Wh does.

V (volt)

The unit of electrical pressure. E-bike packs are rated at 36, 48 or 52 V nominal, built from cells of about 3.6 V each wired in series: ten cells for 36 V, 13 for 48 V and 14 for 52 V.

Cell

A single lithium-ion unit, the building block of a pack. Samsung SDI, LG Energy Solution, Panasonic, Molicel, EVE Energy, Lishen and BAK make the cylindrical cells used in e-bike packs.

18650

A cylindrical lithium-ion cell 18 mm across and 65 mm long. It was the standard e-bike cell through the 2010s and still appears in budget packs.

21700

A cylindrical lithium-ion cell 21 mm across and 70 mm long that holds more energy than an 18650 and has largely replaced it in new e-bike packs. The Molicel P45B is a 4,500 mAh high-power 21700.

NMC

Lithium nickel manganese cobalt oxide, the cathode chemistry in most Western e-bike packs because it stores the most energy per kilogram. NCA (nickel cobalt aluminum) is a close relative.

LFP

Lithium iron phosphate, a cathode chemistry that stores less energy per kilogram than NMC but lasts more charge cycles and resists thermal runaway better. It is common in Chinese electric two-wheelers, swap-network batteries and some seated scooters.

BMS (battery management system)

The circuit board inside a pack that monitors each series group of cells and cuts current on overcharge, over-discharge, overcurrent, short circuit or high temperature. It also balances cells so they charge evenly.

Thermal runaway

A self-heating failure in which a damaged or overcharged lithium-ion cell vents flammable gas and ignites, spreading to neighboring cells in seconds. It causes the e-bike and e-scooter fires covered on battery fires and certification.

CC/CV charging

Constant current, constant voltage: the two-stage charge method for lithium-ion packs. The charger pushes a steady current until the pack reaches full voltage, about 4.2 V per cell or 42 V for a 36 V pack, then holds that voltage while the current tapers off.

Charger

The off-board power supply that converts wall power to the pack's charging voltage and current. A charger must match the pack's voltage and chemistry, and mismatched chargers are a known fire cause.

Cycle life

The number of full charge and discharge cycles before a pack falls to a set share of its original capacity, often 80%. Heat, deep discharge and storage at full charge shorten it.

Swappable battery

A pack exchanged for a charged one at a kiosk instead of charged by the rider. Gogoro runs the largest network in Taiwan, and Chinese operators such as Zhizu serve delivery riders.

LMT battery

Light means of transport battery, the EU Battery Regulation (EU) 2023/1542 category for packs up to 25 kg that power e-bikes, e-scooters and similar vehicles. LMT batteries carry rules on removability, labeling and the battery passport.

Safety standards

UL Standards Govern US Sales, EN Standards Govern Europe

Certification law and fire records are on battery fires and certification.

UL 2849

The UL standard for electrical systems for e-bikes, testing the battery, charger, motor and controller together as one system. New York City requires it for e-bike sales, and the CPSC proposed making it mandatory nationwide in June 2026.

UL 2271

The UL standard for batteries used in light electric vehicles, testing a pack on its own for overcharge, short circuit, crush, impact and fire. It applies to replacement and aftermarket packs.

UL 2272

The UL standard for electrical systems of personal e-mobility devices: stand-up e-scooters, self-balancing boards and similar devices. It is the scooter counterpart to UL 2849.

NRTL

Nationally recognized testing laboratory, a lab recognized by OSHA to certify products to US standards. UL Solutions, Intertek and TÜV Rheinland certify e-bikes to UL 2849.

16 CFR 1512

The CPSC's mandatory requirements for bicycles, covering brakes, frames, reflectors and other mechanical parts. Low-speed electric bicycles under 15 U.S.C. 2085 must meet it.

EN 15194

The European standard for EPAC bicycles: mechanical, electrical and electromagnetic requirements for pedelecs assisting to 25 km/h at 250 W. Compliance supports the CE marking under the EU Machinery Directive.

EN 17404

The European standard for EPAC mountain bikes, published in 2022, which adds off-road test loads to the EN 15194 requirements.

EN 17860

The European series of standards for carrier cycles (cargo bikes), published from 2024, with parts covering terms, mechanical requirements for two-wheel and multi-track bikes, electrical aspects, passenger transport and cargo trailers.

EN 50604-1

The European safety standard for secondary lithium batteries in light electric vehicles, testing packs for electrical, mechanical and thermal abuse. It is the European counterpart to UL 2271.

GB 43854-2024

China's mandatory safety standard for lithium-ion batteries in electric bicycles up to 60 V, in force since November 1, 2024. It works alongside GB 17761 for the vehicle.

Local Law 39

A New York City law of 2023, in force since September 2023, that bars the sale of e-bikes, e-scooters and their lithium-ion batteries unless certified to UL 2849, UL 2272 or UL 2271. FDNY counted 18 lithium-ion fire deaths in 2023 and one in 2025.

Battery passport

A digital record, read through a QR code, of a battery's maker, chemistry, carbon footprint, recycled content and condition. The EU Battery Regulation requires one on every LMT battery placed on the market from February 18, 2027.

Vehicle types

Body Style and Legal Class Are Separate Labels

The full ladder of vehicles and body styles is on the types page.

Longtail

A cargo bike with an extended rear frame and rack that carries children or freight behind the rider, such as the Tern GSD and Yuba Spicy Curry. It rides much like a standard bike (cargo e-bikes).

Front-loader (bakfiets)

A cargo bike with a box or platform between the rider and a stretched-out front wheel, such as the Urban Arrow Family and Riese & Müller Load. The Dutch name bakfiets means box bike (cargo e-bikes).

Cargo trike

A three-wheeled cargo bike, with two wheels at the front carrying a box (Christiania, Butchers & Bicycles) or two at the rear under a platform.

Moped-style e-bike

An e-bike styled like a small motorcycle, with a long bench seat and fat tires, such as the Super73. Sold with pedals and a 20 mph cap it is a Class 2 e-bike; unlocked past 28 mph it is an unregistered motor vehicle.

Speed pedelec

A pedal-assist e-bike that assists to 45 km/h (28 mph), from makers such as Stromer, Riese & Müller and Gazelle. It is a Class 3 e-bike in the US and an L1e-B moped (S-pedelec) in the EU.

Fat tire

An e-bike with tires 4 inches wide or more for sand, snow and loose ground, from Rad Power Bikes, Himiway and Lectric. Wide tires add rolling resistance and cut range on sidewalk.

eMTB

An electric mountain bike with suspension and a high-torque mid-drive, such as the Specialized Turbo Levo or the Amflow PL with the DJI Avinox drive. EN 17404 covers them in Europe.

Folding e-bike

An e-bike with a hinged frame that folds for trains, cars and apartments, from Brompton, Lectric and Fiido.

Conversion kit

A motor, battery, controller and display sold to turn an ordinary bicycle into an e-bike, such as the Bafang BBSHD mid-drive. The CPSC's June 2026 proposed rule would extend battery certification to conversion-kit parts.

Stand-up e-scooter

A kick-style scooter with a deck, a handlebar and a motor, from Segway-Ninebot, Xiaomi and NIU. US states and EU countries set their own speed caps, often 15 to 20 mph in the US and 20 or 25 km/h in Europe.

Seated e-scooter

A step-through electric scooter with a seat and no pedals, from NIU, Yadea, Aima, Segway-Ninebot and Silence. It is a moped in law: L1e-B in the EU, and registered under state moped rules in the US.

LEV (light electric vehicle)

An umbrella term for e-bikes, e-scooters, seated scooters, e-motos and small electric three- and four-wheelers. Standards such as UL 2271 and EN 50604-1 use it for their scope.

Makers and industry

Most E-Bike Brands Design the Frame and Buy Everything Else

OEM

Original equipment manufacturer. In the bike trade it means the brand that sells the finished bike, and "OEM parts" are the drives, batteries and components fitted at the factory, as opposed to aftermarket parts.

ODM

Original design manufacturer: a factory that designs and builds a complete bike that another brand sells under its own name. Many direct-to-consumer e-bike brands source finished models from ODMs in China and Taiwan.

Contract manufacturer

A factory that builds to another company's design. Giant and Merida in Taiwan build bikes for other brands as well as their own, Yamaha builds Giant's SyncDrive motors, and Brose builds Specialized's motors.

System supplier

A company that sells the motor, battery, display and controller as one matched set to bike brands. Bosch eBike Systems, Shimano, Yamaha, Bafang, Ananda and DJI Avinox are the main ones.

Direct-to-consumer (D2C)

A brand that sells online and ships to the buyer, bypassing bike shops, such as Rad Power Bikes, Aventon and Lectric. Many D2C bikes use hub motors and Chinese components.

IBD (independent bike dealer)

A locally owned bike shop that sells and services bikes from brands such as Trek, Specialized and Giant. Bosch, Shimano and Yamaha route drive service and software updates through these dealers.

Electric two-wheeler maker

The Chinese companies, led by Yadea and Aima, that build e-bikes and electric scooters by the millions for China's GB 17761 market and export. Yadea also builds seated scooters sold in Europe and Southeast Asia.