Dual-motor e-bikes: what the second motor actually buys you

Dual-motor e-bikes — one motor in each wheel — are marketed hard on torque, hill climbing and all-wheel traction. They are genuinely fun. They are also the category where Australian buyers most often end up with something they cannot legally ride.

The legality problem, up front

A bicycle with an electric motor is only legal to ride as a bicycle in Australia if it stays within the power and speed limits. The national standard is a pedal-assisted bike capped at 250W continuous with assistance cutting out at 25km/h. Some states permit higher-powered devices in limited circumstances, and the limits differ sharply between them.

Two 750W hub motors is not a 250W bicycle. Above the limits, a device is legally closer to an unregistered motorcycle — which generally cannot be registered, cannot be insured as a bike, and cannot lawfully be ridden on roads, paths or bike lanes. Fines are substantial.

This is not a reason never to buy one. It is a reason to know what you are buying and where it can be used — private property, or a state that permits it.

What the second motor is actually good at

• Loose surfaces. Sand, gravel and wet grass are where all-wheel drive earns its keep.
• Steep starts under load. Two motors sharing the work run cooler than one motor at its limit.
• Redundancy. A failed controller on one wheel still leaves you able to ride home.

What it costs you

• Range. Two motors draw roughly twice the current for the same speed. Dual-motor bikes need much bigger batteries to achieve ordinary range, and most people ride them in single-motor mode to get it.
• Weight. Frequently 35–45kg. Consider whether you can lift it onto a rack, carry it up stairs, or push it home flat.
• Braking. A heavy, fast bike needs brakes to match. Look for hydraulic discs, not cable-operated ones.

Buying one second-hand

Ask how it has been ridden. A dual-motor bike used hard off-road has worked its bearings, spokes and brakes far more than the odometer suggests. Spin both wheels and listen for dragging or notchiness, test both motors independently if the controller allows it, and check that both hubs run at the same temperature after a climb.

Confirm the battery, charger and both controllers carry certification markings, and that the original charger is included.

Listings on eRideList show how a device compares against each state's limits, based on the wattage and top speed the seller declares — so check that panel before you commit. Our rules and battery safety page sets out the limits in full.