Our response to an inquiring customer this week is the secret to avoiding one of the biggest mistakes for first- time e-bike buyers.
“I‘m impressed by the combination of specs on your bike but is a 250W motor enough? I’ve been comparing your bike to others that advertise 500W or 750W motors. There's a big hill near my house and I want to make sure I can make it up without an issue.”
Considering the motor size in isolation is one of the biggest mistakes first time e-bike buyers make. Unfortunately, there isn't a standard in place when advertising motor size to help translate the true power of a motor to consumers.
When comparing e-bike motors, you need to ask two questions to know if that motor will suit your riding needs (a.k.a. if it will be powerful enough to boost you up those tough hills).
Is the motor a mid-drive motor or a hub motor?
What is the motor's torque rating?
Motor size alone is not enough to know how powerful the motor will feel. You must also consider the torque rating.
Torque is measured in Newton meters (Nm) and represents the force that propels you up inclines. It is the true power behind any e-bike motor.
Putting the two together looks like this, for instance:
A 250W hub motor typically possesses 35Nm of torque. A 500W hub motor will have 45-60 Nm of torque. And a 750W hub motor will have between 75-100 Nm of torque. The downside of a hub-motor is the inefficient use of torque through the drive train, resulting in a less efficient boost than a mid-drive motor.
Mid-drive motors with a 250W rating offer torque variations between 40Nm and 95Nm.
A mid-drive motor with a higher torque rating will be more efficient and feel more powerful than a hub-motor with a larger motor size.
This means that a 250W mid-drive with 80 Nm of torque will have a much easier time climbing hills than a 500W, 60 Nm hub drive motor.
So back to our friend's question, "Is a 250W motor enough"? The answer is, it depends whether it’s a mid-drive motor and what the torque rating is. When designing the TuffHill e-bike, we took motor size and torque rating into careful consideration. We chose the perfect combination of a 250W mid-drive motor with 80 Nm of torque, which is more than enough power to conquer any hill in Calgary.
Two More Pieces of Motor Advice
1. Bigger Isn’t Always Better There are legal restrictions in most jurisdictions that limit where you can ride an e-bike with a motor larger than 500W. Motor Wattage over 750W and 100 Nm of torque means more wear and tear through your drivetrain. This size of motor is incompatible with a belt drive and most internal gear hubs. It also affects the feeling of riding a bike. Most people we talk to want an e-bike that still feels natural to ride. A 250W mid-drive motor gives you a powerful boost without compromising the feeling of riding a bike. You will still get exercise while pedaling but can also climb steep hills without sweating buckets or having to get off your bike and walk it up the hill. Another thing to note is the larger the wattage, the more battery power you will use, resulting in shorter range capacities. The TuffHill e-bike's 250W mid-drive motor with 80 Nm of torque is the perfect combination to maximize power and range efficiency. It's partially why you can ride over 150 km on a single charge. 2. The Efficiency of the Motor Matters Hub motors apply torque directly in the wheel, which makes for a less efficient ride overall. Mid-drive motors, on the other hand, multiply the torque through the gears. This means you will always have an easier time riding uphill with a mid-drive motor and you'll drain less battery doing it. For most older riders or someone who frequently rides up big hills, we recommend a mid-drive motor with 60-80 Nm of torque.
Don't Buy an e-Bike Before You Know What the Boost Feels Like
Is 250 Watts enough for you? The only way to truly know what motor is right for you is to ride the bike up a hill.
Come for a test ride and feel how the 250W mid-drive motor with 80 Nm of torque let’s you climb with ease.