The e-bike glossary
The spec-sheet jargon, in plain English. What each term means, and what it actually tells you when you're choosing a bike.
Nominal watts
The steady power a motor can hold all day. This is the honest, everyday number — the one to compare bikes on.
Nominal wattage is the power an e-bike motor can put out continuously, without overheating. It's the number that actually describes how the bike feels most of the time: cruising, holding speed, easy climbing. Brands sometimes bury it in favor of a bigger 'peak' figure, but nominal is the one to compare bike to bike. In the US, a motor's nominal rating is also what legally defines it as an e-bike (typically capped at 750W).
Also called: nominal power, nominal wattage, continuous power
Peak watts
The short burst a motor hits for a moment — pulling from a stop or cresting a hill. Impressive on paper, but you won't feel it most of the time.
Peak wattage is the maximum power a motor can produce in a brief burst, such as accelerating from a stop or punching over a steep rise. It's often roughly double the nominal (continuous) figure, which is why brands love to advertise it. Because it only applies for seconds at a time, peak power is a poor way to compare bikes — two motors with the same headline peak can feel completely different day to day. Judge a bike on its nominal watts and its torque, not its peak.
Also called: peak power, peak wattage, max power
Torque
The twisting force that gets you moving and pulls you up hills, measured in newton-meters (Nm). Higher torque means stronger acceleration and easier climbing.
Torque is the rotational 'push' a motor delivers to the wheel, measured in newton-meters (Nm). It's what you feel launching from a stop and grinding up a hill — more than top speed, torque decides how strong and effortless a bike feels. As a rough guide: 40-50 Nm is fine for flat city riding, 65-80 Nm handles most hills comfortably, and 85 Nm and up is real climbing muscle for loaded cargo or steep off-road. Torque matters more than raw wattage for how a bike actually rides.
Also called: nm, newton meters, newton-meters
Watt-hours
The size of the battery's 'fuel tank' (Wh). More watt-hours means more miles before you recharge.
A watt-hour (Wh) is the unit of an e-bike battery's total energy — think of it as the size of the fuel tank. You can calculate it by multiplying voltage by amp-hours (a 48V battery with 14Ah holds about 672Wh). More watt-hours means more range, all else equal, so Wh is the fairest way to compare batteries across brands that quote volts and amp-hours differently. As a rough rule, most riders use 15-25 Wh per mile, so a 500Wh pack realistically covers 20-35 miles of typical assisted riding.
Also called: wh, watt hours, battery capacity
Hub motor
A motor built into the center of a wheel (usually the rear). It pushes the wheel directly — simple, reliable, and quiet, with a smooth and steady feel.
A hub motor sits inside the hub of a wheel, usually the rear, and drives that wheel directly. It's the most common e-bike motor because it's affordable, low-maintenance, and quiet, and it delivers power in a smooth, even way. The trade-offs versus a mid-drive: it doesn't use the bike's gears, so it's less efficient on long steep climbs and can drain the battery faster on big hills, and it puts more weight out at the wheel. For flat-to-rolling commuting and casual riding, a hub motor is usually all you need.
Also called: hub-drive, rear hub motor, hub drive
Mid-drive motor
A motor mounted at the pedals that drives the chain, so it uses the bike's gears. It climbs steep hills better and feels more like a regular bike, but costs more.
A mid-drive motor sits at the crank (where the pedals attach) and powers the chain rather than a wheel directly. Because it drives through the bike's gears, it's far more efficient on steep, sustained climbs and gives a natural, responsive, bike-like feel. It also centers the weight low for better handling. The downsides are cost and maintenance — mid-drives are pricier and add wear to the chain and cassette. They're the choice for serious hills, mountain riding, and riders who want the most natural power delivery.
Also called: mid drive, mid-drive, center motor
E-bike class
A simple 1/2/3 system for how an e-bike assists. Class 1: pedal-assist to 20 mph. Class 2: adds a throttle. Class 3: pedal-assist to 28 mph. It decides where you're allowed to ride. Many bikes are switchable between classes.
E-bike class is a three-tier system (used across most US states) that describes how a bike assists and how fast. Class 1 gives pedal-assist only, up to 20 mph. Class 2 adds a throttle you can use without pedaling, also capped at 20 mph. Class 3 is pedal-assist up to a faster 28 mph, with no throttle above 20 mph. Class matters because it governs where you can legally ride: Class 1 and 2 are welcome on most bike paths and trails, while Class 3's higher speed is often restricted to roads and bike lanes. Many modern bikes are switchable: a spec like "Class 1-3" does NOT mean three separate bikes, it means one bike you can reconfigure in the settings or on the display. You pick the mode for where you're riding: dial it down to Class 1 or 2 to stay legal on a shared bike path, or set it to Class 3 for full speed on the road. Switching the class also changes whether the throttle is active (the Class 2 setting is what turns ride-without-pedaling on) and the top assisted speed, so it's really a single control over speed, throttle, and where you're allowed to ride.
Also called: class 1, class 2, class 3
Throttle
A trigger or twist grip that powers the bike without pedaling, like a scooter. Handy for hills and starts, but it drains the battery faster than pedal-assist.
A throttle lets you drive the motor on demand without pedaling — usually a thumb trigger or twist grip. It's genuinely useful for pulling away from a stop, easing up a hill, or resting your legs. The catch is efficiency: riding on throttle alone uses far more battery than pedal-assist, so your real range drops. A throttle also makes a bike Class 2 (or Class 2/3 switchable), which affects where it's allowed. Great to have as an option; not the way to ride if you want maximum range.
Also called: throttle vs pedal-assist
Pedal-assist
The motor adds power only while you pedal, multiplying your effort. It stretches your range and feels like a strong tailwind.
Pedal-assist (sometimes 'PAS') means the motor helps only while you're pedaling, amplifying your own effort rather than replacing it. You pick an assist level — low for maximum range, high for the least effort — and the bike tops up your pedaling. It's the most efficient way to ride an e-bike, so it delivers noticeably more range than using a throttle. How natural it feels depends on the sensor the bike uses to decide how much help to give (see cadence sensor vs torque sensor).
Also called: pas, pedal assist, assist
Cadence sensor
Decides motor help based on whether you're pedaling, not how hard. Power comes in steady, in steps — simple and common on budget bikes, but a little less natural.
A cadence sensor triggers the motor based on the fact that you're pedaling — it detects wheel or pedal rotation and delivers a set level of assist regardless of how hard you push. It's simple and cheap, which is why it's common on budget e-bikes. The feel is 'on/off': power arrives in steady steps and can lag slightly when you start or stop pedaling. It works perfectly well for relaxed commuting, but a torque sensor feels more responsive and bike-like.
Also called: cadence
Torque sensor
Measures how hard you actually push and matches the motor to it, in real time. The result feels natural and responsive — like a stronger version of your own legs.
A torque sensor measures the actual force you put into the pedals and scales the motor's help to match, moment to moment. Push harder and you get more; ease off and it backs away. This makes the bike feel intuitive and bike-like — the motor amplifies your effort instead of switching on in fixed steps like a cadence sensor. It's also more efficient, since power tracks your real demand. Torque sensors are a mark of a nicer e-bike and are well worth seeking out if a natural ride feel matters to you.
Also called: torque-sensing, cadence vs torque sensor
Claimed range
The 'up to X miles' figure is a best case — lowest assist, flat ground, light rider. Plan on meaningfully less in real riding.
Claimed range is the 'up to X miles' number a brand advertises, and it's almost always a best-case lab figure: lowest assist level, flat ground, a light rider, mild weather, no throttle. Real-world range depends on hills, your weight and cargo, wind, cold, tire pressure, and how much you lean on the motor — all of which pull the number down. A realistic planning figure is often half to two-thirds of the claim. Use watt-hours (battery size) as a more honest cross-brand comparison than the headline range.
Also called: up to range, up to miles, range claim
Payload capacity
The most total weight a bike is rated to carry — rider plus cargo plus any passenger. Not the same as the bike's own weight.
Payload capacity (or max load) is the total weight an e-bike is engineered to carry safely: the rider, any cargo, and a passenger or child seat combined. It's a critical spec if you're a heavier rider, haul groceries, or carry a kid — exceeding it stresses the frame, brakes, and wheels. Watch out for a common mix-up: payload is NOT the bike's own weight, and some listings blur the two. A 350 lb payload on a 70 lb bike leaves roughly 280 lb for rider and cargo.
Also called: max payload, payload, max load
Suspension travel
How far a suspension fork can compress to absorb bumps, measured in millimeters. More travel soaks up rougher ground.
Suspension travel is the distance a fork (or rear shock) can compress to absorb impacts, measured in millimeters. On e-bikes it usually refers to the front fork. Roughly: 60-80mm smooths out cracks and curbs for comfort commuting, 100-120mm handles gravel and light trails, and 140mm and up is built for real mountain-bike terrain. More travel adds capability and comfort on rough ground but a little weight and cost. A 'hardtail' has a suspension fork up front and a rigid rear; 'full-suspension' adds a rear shock too.
Also called: travel, fork travel, 120mm travel
Hydraulic disc brakes
Brakes that use fluid instead of a cable, so they stop harder with a lighter pull and need less upkeep. A real upgrade over cable (mechanical) brakes, especially on a heavy e-bike.
Hydraulic disc brakes use fluid pressure — squeeze the lever and fluid clamps the pads onto a rotor at the wheel. Compared with cable-pull (mechanical) disc brakes, they deliver more stopping power for less hand effort, feel more controlled, self-adjust as the pads wear, and hold up better in wet weather. That matters a lot on e-bikes, which are heavy and fast enough that confident braking is a safety feature, not a luxury. They cost a little more and need occasional bleeding, but for most riders they're well worth it.
Also called: hydraulic disc, hydraulic brakes, hydraulic disc brake
Definitions written by the eBikeGenius team to help first-time buyers make sense of e-bike specs. Wherever these terms appear in our reviews, tap the underlined word to see the short version.