What do electric bike motors offer, and what are their differences?
The electric bike motor is probably the most critical part of a powered bicycle, along with the battery itself.
Most users ask what could be the best motor to fit when converting their standard bikes.
To choose the right one, it is essential to know the following:
– classification,
– differences and,
– capabilities.
Last but not least, the local regulation will heavily affect all the above points.
Read More: Electric Bike Laws – Know Them Before Riding One
In this guide, you will find a full explanation of those four (4) main points.
Table of Contents
Electric Bike Motor Brands – Most Known
Having the right motor when selecting the e-bike and understanding the purposes of buying one is essential.
I recommend shopping for motors from major manufacturers such as Bosch, Shimano, and Yamaha to make your life easier.
Leading brands ensure excellent customer service and genuine and reliable parts.
Of course, these motors are expensive. Other more affordable ones, such as Bafang, also do a great job, but a few users do not support this.
The best advice is to ask your local dealers or other e-bike enthusiasts regardless of your purchase.
How Much Power Does an E-Bike Need?
The motor’s power is crucial when buying an electric bicycle. Generally speaking, the higher the wattage, the more powerful the motor will be.
If climbing steep hills is part of the journey, more power will be beneficial (more than 500 w), but it is not the only factor to consider.
A high percentage of the motors in the market offer a peak power of 250 watts to 750 watts. Higher than 750 watts will jump to the next category as a “power on demand” e-bike, which is strongly regulated by local laws.
250w and 500w motors are commonly fitted for commuter models like the XDS E-Cruz step-thru and folding electric bikes. By contrast, 750 watts are typically seen in models offering throttle features like the Ecotric Tornado MTB (not limited, though).
The torque feature is the other factor that can influence the motor power output requirement. I discussed this in the following section.
Heavy Weights and Good Acceleration: The Torque Concept
The torque (measured as Newton-meter (Nm)) is an essential factor to consider if you need an instant push when taking off or carrying additional weight.
For example, think about a car that operates with gasoline or diesel.
Gasoline vehicles reach the desired speed in less time, while diesel vehicles will take longer.
This is due to the torque provided by each motor and fuel ignition point.
Of course, in this case, no fuel is involved but watts per hour.
Recent motors in the industry have shown that having a higher torque can help you reach the maximum speed in less time.
Weight matters
In the case of your e-bike, it is essential to consider whether you will be carrying additional cargo (such as a small trailer, similar to what the Phantom Santa Fe Classic features) plus your body weight.
A heavier total weight means a higher torque would be better.
Torque range
Typically, the torque for low to medium e-bikes is between 40 to 60Nm. Anything above 60Nm would be considered as high torque.
To determine what power and torque you likely need, it is advisable that:
– Think about your usual riding paths (flat or hilly areas).
– The weight you are likely to carry over your trip.
Try out different models with various power and torque levels. See what feels more appealing for your needs.
Electric Bike Motor Types
Consider several points when choosing the e-bike motor type, including whether you choose a geared hub, direct drive, or a mid-drive.
Mid-drive type
A mid-drive motor, sometimes called a crank drive, diverts the power directly to the chain, followed by the whole shifting system.
The good side
– They are excellent for hill climbing and offer an improved center of gravity, better weight distribution, and improved handling, precisely what the Cube Reaction Hybrid Pro 500 has.
– These high-tech models can detect your pedaling cadence, which tells the motor how much assistance to deliver, saving battery power.
Some also contain torque sensors, as seen in expensive high-performance e-MTBs like the Specialized Turbo Levo SL.
– The sensors respond according to the effort you put into pushing the pedals forward. They also react according to how the pedals rotate.
The questionable side
One downside is that they can be more noisy than hub drive models, in case this is a deal breaker.
In most cases, they are battery-efficient and best for hill climbing. However, they are more expensive compared to the hub drives.
If you are thinking of mountain biking, this would be the motor classification to look at.
Geared hub types
As its name says, a geared hub motor has internal gears inside its casing. In some instances, they can have more torque, so climbing hills is not a problem.
A geared configuration will help you travel freely (not resistant due to its internal mechanism) when not using the motor. It also means the motor will not help you “hold” the e-bike when going downhill, so your brakes will work harder.
Free-wheel means the internal mechanism of a motor does not create any resistance when its parts are not in operation, which is great if you lose battery power.
Geared motors are not designed to maintain high speeds.
If you are cruising, you will have to pedal more, and your battery will drain faster. However, geared e-bike motors are more common than direct-drive ones (explained below).
Direct drive (hub) models
Direct-drive, also called hub motors, is the more affordable choice and is much easier to fit and maintain. This is mainly because of its internal design.
The positive points are
– The motor will cool down faster due to its considerably large size.
– Allows for regenerative braking, which charges up the battery when you are not pedaling (it is not much, though).
– Can maintain high speed better.
The flip side
– The wheel does not spin freely, so there is a lot of resistance, translating to pedaling more arduous if you run out of battery.
– These are heavier than the other motor versions so the e-bike will be heavier.
– Often, they are limited to one speed, like the Hummingbird folding electric bike. As a result, they are likely to struggle when climbing hills (low torque).
Final Thoughts
e-Motors for bicycles have evolved from brushed to brushless DC motors.
A motor capable of generating good speed and torque will likely cost more.
Usually, mid-drive motors are fitted in e-bikes for all purposes; however, they are more commonly used in electric mountain bike models.
When buying an electric bicycle, consider what you want to achieve (more speed, more torque, climbing hills, mountain biking, cruising). The motor selection will make a difference between pedaling hard or just cruising.
Are you looking for electric bike motor kit options?
We recommend reading our Electric Bike Kit 2024 Guide for Beginners to find the best ones based on customer reviews.
2 Comments
I have a motor in a bike rim is 36v 750w, i got 3 12 v 10 ah and only runs like 5 minutes, dont know why and please advise me what kind of baterry do i need so it could run more time or a couple of miles.
Hi Freddy, thanks for your question.
A 750watts motor usually requires a battery that can deliver more than 36v. In this case, I think your voltage and amps are low for the power required.
Considering I have no idea what ebike you are riding, my first suggestion is to go to your preferred local bike store and ask for suggestions (dimensions of the battery to fit the frame); nevertheless, in terms of the battery chemistry, I would get inclined to get a 48v, 15 to 17Ah battery. This will ensure you have a continuous discharge current to the motor, then cover more distance and keep up with the power demanded.
Cheers,
Andrew.