E-bike motor wattage explained

Rated, peak and nominal

Three words appear on motor specifications and they are not interchangeable. Getting them straight is most of the work.

Rated (or nominal) power

The output a motor can sustain more or less indefinitely without overheating. "Nominal" and "rated" are used interchangeably in practice, and this is the figure US law generally refers to. It is the number that describes what the bike does on a long climb, into a headwind, on a hot day — the moments that actually test a motor.

Peak power

The maximum the motor and controller can produce in a short burst, typically for seconds rather than minutes, before heat forces a reduction. Peak power is real and useful: it is what pulls a heavy bike away from a standstill or over a short rise. It is simply not what the bike does continuously.

The marketing incentive is obvious. Peak is roughly 1.5 to 3 times rated on most systems, so a brand quoting peak gets a headline number two or three times larger for the same hardware. A listing that says "3000W" without qualification is almost always quoting peak.

When you compare bikes, compare rated against rated. Comparing one brand's peak with another's rated is the most common mistake in this part of the market, and it will reliably point you at the wrong bike.

What a wattage figure actually predicts

Watts measure the rate of doing work. On a bike, more watts broadly means faster acceleration, a higher speed the motor can hold, and more capacity to move mass uphill. A 1000W-rated motor has real headroom: a fit cyclist sustains something like 150 to 250 watts, so the motor is contributing several times what a strong rider can.

What a wattage figure does not tell you:

• How the power is delivered. Two 1000W motors can feel completely different depending on winding, controller tuning and where in the speed range the torque arrives.
• How it climbs. Climbing is a torque problem at low wheel speed, and watts are torque multiplied by rotational speed. A motor producing its rated power at 25 MPH may be producing very little of it at 5 MPH on a steep pitch.
• How long it holds. Thermal behaviour is not in the wattage figure at all.
• How efficient it is. Rated output says nothing about what the pack pays to produce it, which is a range question. That is handled in our battery and range guide.

The practical version: past about 750W, extra rated watts buy increasingly less on flat ground and increasingly more on hills and under load. If you commute on the level, the difference between 750W and 1000W is barely perceptible. If you climb, it is not.

Torque is the number you actually want

Torque is rotational force, measured in newton-metres. It is what gets a loaded bike moving from rest and what keeps it moving up a gradient at walking pace. Watts describe the rate of work; torque describes the shove.

For a rough sense of scale on hub-motor bikes: around 45 to 60Nm is adequate for gentle terrain, 65 to 80Nm handles most real hills with an average rider, and above 80Nm starts to feel effortless on steep ground. Mid-drive systems quote torque at the crank rather than the wheel, so the numbers are not directly comparable between the two types.

Here is the awkward part. AMYET does not publish a torque figure in newton-metres for the G60, the EB26 or the S8. Neither do most brands at this price. That means climbing ability on these bikes cannot be stated from the specification sheet by anyone — us included — and any review that tells you how a bike climbs without either a torque figure or a physical test is guessing. We say so rather than fill the gap, which is the approach set out on our how we review page.

What you can reason about is the indirect evidence. The S8 is the only one of the three with two driven wheels, and AMYET pairs it with a 35° maximum slope claim, hydraulic brakes and full suspension — a coherent set of choices for steep ground. The single-motor bikes carry no comparable claim. If your route is genuinely hilly, our e-bike for hills guide works through what to look for.

Hub motor or mid-drive

This distinction matters more than the wattage figure printed beside it, because it decides whether the motor can use the bike's gears.

Hub motors

The motor sits inside the wheel hub, usually the rear, and drives the wheel directly. Its torque reaches the ground unmultiplied, whatever gear you are in. Hub motors are cheap, mechanically simple, quiet, and they put no extra load on the chain — which is why essentially every bike in the budget fat-tire category, all three AMYET models included, uses one.

The weakness is the steep, slow climb. A hub motor forced to turn slowly under high load draws heavy current and converts a growing share of it into heat rather than motion. It cannot drop a gear to escape.

Mid-drive motors

The motor drives the crank, so its output passes through the drivetrain. Shift to a lower gear and the gearing multiplies motor torque exactly as it multiplies yours. A 500W mid-drive in a low gear will out-climb a 1000W hub motor on a steep pitch, and it will stay cooler doing it, because it can spin faster while the wheel turns slowly.

The costs are price, chain and cassette wear, and complexity. Below roughly $1,500 mid-drives are rare in the US direct-to-consumer market, so for most buyers in this bracket the practical question is not which type but how well the hub motor is matched to the terrain.

Geared and gearless hub motors

Within hub motors there is a second split that listings rarely mention.

A geared hub contains internal planetary reduction gearing, so the motor spins fast while the wheel turns slowly. That produces more torque for a given size and weight, and it usually includes a freewheel so the motor does not drag when unpowered. The trade is a small amount of gear noise and a wearing part inside the hub.

A gearless or direct-drive hub has no internal gearing: the axle is the stator and the shell rotates around it. It is nearly silent, has almost nothing to wear out, and can support regenerative braking. It is also heavier for the same torque and less efficient at low speed, which is precisely where climbing happens.

AMYET describes the EB26 and S8 motors as brushless but does not state geared or gearless for any of the three bikes. That is a common omission. If you are choosing between two otherwise similar bikes and one specifies a geared hub, that is a small point in its favour for hilly riding.

Why a 7-speed drivetrain still matters on a hub-motor bike

It is tempting to dismiss the gears on a hub-motor e-bike. The motor is in the wheel; the cassette cannot help it. All three AMYET bikes list a 7-speed drivetrain, and it earns its place for three separate reasons.

1. It lets you contribute usefully. Your own 150 watts only arrive if your legs are turning at a cadence that produces them. On a long climb, spinning a low gear at 80rpm adds real power for twenty minutes; grinding a high gear adds almost nothing and hurts.
2. It keeps the motor cooler. Every watt you add is a watt the motor does not have to produce. On a sustained climb, that is the difference between a motor that holds its output and one that heats up and starts backing off.
3. It makes the bike work with a flat battery. A 70-plus pound fat-tire e-bike is hard work to pedal unassisted, but a 7-speed range means hard work rather than impossible. A single-speed e-bike with a dead pack is a very heavy scooter you have to push.

Seven speeds is modest — a wide-range 8 or 9-speed cassette would be better on steep ground — but it is enough to matter, and it is more than some cheaper bikes offer.

Heat, and why bikes lose power on long climbs

A motor converts electrical energy into motion, and everything it fails to convert becomes heat. A hub motor is a sealed aluminium shell with limited surface area and no fan, so on a long climb the heat accumulates faster than it can escape.

What happens next depends on the controller. A well-designed system monitors temperature and progressively reduces current — you feel the assist fade, which is frustrating but protective. A cheaper system without thermal monitoring simply runs hot, and sustained heat degrades the magnets and the winding insulation permanently.

This is the practical reason rated power matters more than peak. Peak power is a promise about the first few seconds. Rated power is a statement about thermal equilibrium — what the motor can shed heat fast enough to keep producing. On a two-mile climb, the rated figure is the one you are riding.

Two habits help on any hub-motor bike: pedal genuinely on climbs to reduce the motor's share of the work, and avoid holding the throttle wide open at low speed for minutes at a time, which is the single hottest thing you can ask a hub motor to do. AMYET does not publish thermal specifications, controller detail or a cutback behaviour for any of the three bikes, so this is category-level guidance rather than a description of these models.

Controller amps: the number nobody prints

Power is voltage multiplied by current. On an e-bike the battery sets the voltage and the controller decides how much current it will pass, so the controller is the component that actually determines the power ceiling. Fit a bigger controller to the same motor and the bike gets faster; fit a conservative one and a 1000W motor never sees 1000W.

Working the arithmetic on a 48V system:

• 48V × 15A = 720W
• 48V × 20A = 960W — roughly a "1000W" bike
• 48V × 25A = 1200W
• 48V × 31A ≈ 1500W — roughly a "1500W peak" bike

There is a second consequence worth noticing. The S8's 3000W combined peak, drawn from a 1200Wh pack, would empty the battery in about 24 minutes if it could be sustained. It cannot be, and that is the point: peak figures are limited by the pack as well as by the motor. A big peak number on a small battery is a number you can only visit briefly.

Almost no brand in this segment publishes controller amperage. When comparing two bikes with identical wattage claims, the one that publishes controller specification is telling you something the other is not.

Wattage, the law and the three-class framework

US e-bike regulation is set at state level and it uses two levers: motor power and assisted speed.

The federal consumer-product definition of a low-speed electric bicycle refers to a motor of less than 750W, and many states have adopted 750W nominal as the ceiling for a vehicle to be treated as a bicycle rather than as a moped or motor vehicle. That sits awkwardly with a market full of bikes rated at 1000W and marketed at 1500W or 3000W peak. Enforcement is uneven and many riders never encounter it, but the legal position is what it is, and it can surface after a collision or an insurance claim rather than at the roadside.

The three classes

• Class 1: pedal assist only, assistance ends at 20 MPH.
• Class 2: throttle permitted, assistance ends at 20 MPH.
• Class 3: pedal assist to 28 MPH, frequently with restrictions on shared-use paths.

AMYET claims up to 28 MPH for the EB26, which lands exactly on the Class 3 ceiling and makes it the easiest of the three to place legally. The G60 and S8 are both claimed at up to 32 MPH, which is outside all three classes in states that use this framework. Most bikes in the category ship with a configurable speed limit in the display settings, so the practical answer is usually to set the bike to comply — but check your own state, county and city rules, because path and bike-lane rules are often stricter than road rules.

The wider point for a buyer: a headline wattage figure that cannot be legally used where you ride is not a feature. Our how to choose an electric bike guide puts this in order against the rest of the decision.

Dual motor is a different question

Two motors is not simply more watts. It is a traction decision, and it deserves separate reasoning.

A single rear hub motor puts all its torque through one contact patch. On loose gravel, sand, snow or a wet steep climb, that patch is the limit — you can add power and the wheel will spin rather than drive. A second driven wheel splits the torque across two contact patches and converts more of it into forward motion. That is why the S8 exists, and why AMYET pairs its 2 × 1000W rated, 3000W peak claim with a 35° maximum slope figure.

The costs are consistent and predictable: more weight, more expense, more complexity, and higher energy consumption when both motors are driving. AMYET's 70 to 75 mile claim on the S8's 1200Wh pack is realistic only under single-motor, low-assist conditions — the reasoning is set out in why claimed range is never the range you get.

For flat commuting, a second motor is capability you pay for and rarely use; the $360 gap between the G60 and the S8 buys nothing on level ground. For hills, loose surfaces and heavy loads it changes what the bike can do. Our single vs dual motor guide takes the decision apart properly, and the G60 vs S8 comparison puts the two bikes side by side.