Rear hub motor with speed or torque sensors: which one is best?

If you're looking for your first ebike you'll notice soon that there's a great variety of models, each one with different tech specs and prices. But, what's different, and why?

Talking about ebikes, first of all we must mention that you can find two macro categories of motor units: the mid motor and the rear hub motor. Today we focus on the second category of electric motors integrated in the rear wheel hub.

In that article, we want to go even deeper in detail and analyze the main difference between the hub motor equipped with a cheaper Speed Sensor or a more sophisticated hub motor with a Torque Sensor. We are going to see how they work and "feel"while riding, it will be useful to understand which one is more performant and best for your needs.

In general, most affordable rear hub motors are equipped with a Speed Sensor that reads the ebike pedals movement and activates the motor to quickly reach the max speed. On the other hand, more sophisticated rear hub motors are equipped with a Torque Sensor that reads the strength and speed of rotation about the crank, giving a more controlled powerful output, for a natural pedaling feeling.

Those are some of the main differences and we are going further with more details, but first let's quickly introduce electric bikes, talking about how they work and the main tech specs. 

Ebikes: powered by an electric motor

Modern ebikes are equipped with an electric motor powered by a battery, a power unit that in Pedelec models helps the cyclist while pedaling or, in the case of electric bikes equipped with a throttle, the motor pushes the bike without even having to pedal (in the full electric mode), making it much more like an electric scooter.

These two distinct modes can also coexist, in fact on the most versatile e-bikes we find both functions that can be easily switched while riding according to needs: so we are going to spend some words about the PAS mode and the Full Electric mode.

PAS mode means pedaling assistance, the electric motor helps the cyclist only while pedaling to give an "effortless pedaling feeling" with a light actuation of pedals, even when the street is going uphill. It's like pedaling a standard bike with "professional cyclist training on legs".

Full Electric mode can be activated by the throttle, twisting it or pushing it (finger throttle). The motor gives the power to the wheel and the electric bike moves with the motor only propulsion. It's equivalent to an electric scooter.

As a drowback, Full Electric mode requires more energy and drains the battery quickly.

If you're looking for your first ebike you're also wondering what Watt and Torque are, so we are going to spend some words about it.

Watt Power and Torque

The Hub engines are available with different specifications regarding the peak power and torque. Two values expressed respectively in Watt (W) and Newton Meter (Nm) for the torque. Let's simplify the argument and say that in general Watts can be converted to a higher maximum speed, and on the other hand the torque gives more acceleration and "push power".

In general, more watts gives the ebike motor a higher current flow that can be converted to more max speed: we can explain Watt power by comparing it to the horsepower value for a traditional fuel motor. More horsepower will give your car more speed, like as more Watts will give more speed to an electric bike.

Torque is needed to be more powerful and perform while going uphill, with carrying heavy weights and while riding in hard off road terrains like for example sand, snow and dirt. Torque also contributes to speed up faster to the max speed, infact more torque will give you a quicker acceleration.

More torque also means less seconds to reach the max speed, and faster uphill performances.

A good modern e-bike balances the Watt power with a good Torque amount, to assure high speed, acceleration and full support in most challenging terrains and uphills.

Good motors starts with at least 500W but they’re even better with 750W power.

Speed sensor: cheaper and "less natural pedaling feeling"

Cheaper ebikes are equipped with an affordable hub motor with a Speed Sensor that reads the pedal movement and brings the motor to the max speed according to the assistance level.

Electric bikes can be used with different assistance levels, in general 3 or 5 levels, each one having a different top speed limit: in general 1° level has the lower speed and 5° one has the max speed and higher torque and acceleration.

The Speed Sensor will bring you straight to the top speed of the level that you're using, regardless of the power that you put on pedals and the speed of the crank rotation. Example: you can use the last assistance level (5) and move pedals slowly, the bike will bring you straight to the top speed, not considering the effective cyclist speed over pedals.

The cyclist can “fake the pedal movement” and the motor does 90% of the job and consequently it consumes a lot of battery, that will mean less battery life on a single charge.

Another drawback about the Speed Sensor is the delay between the pedal movement and the motor engagement moment. With a Speed Sensor the cyclist will feel like the first pedal movement it's all on him charge, then the motor will start to release power.

That's a bad feeling especially if you are starting to pedal uphill or from the traffic light.

And on the other hand, when you stop moving pedals, the motor power stop is delayed about 1-2 seconds, in which the motor will continue to push you forward. It's a weird feeling especially while you're slowing down to approach a curve.

Torque Sensor: "effortless natural feeling"

The Torque Sensor is more sophisticated, and reads the crank rotation speed. It means that the motor will help the cyclist according to his needs of power.

If you pedal slowly the bike will remain slow and easy to control, but when you push over pedals it will release the power to give you speed and quick acceleration.

The Torque Sensor contributes to giving you a natural pedaling feeling, you will feel "infinite power on your legs" but in a controlled way. It also contributes to lower the battery consumption with less electric energy waste, giving you more battery range on a single charge.

The motor reads the crank movement and gives power in the same moment, so assistance delays are reduced to very little fractions of seconds.

So, the Torque Sensor It's definitely more efficient and pleasant for those who like to pedal with the precious help of an electric motor. The right choice for who wants to keep himself fit and healthy, with the precious electric help anyone can be back on the bike, including elders.

Meebike are equiped with Torque Sensor

The new ebike Meebike Gallop is powered by a performing rear hub motor with a Torque Sensor, to provide the rider with a natural pedaling feeling, smooth power, quick acceleration and speed.

The Brushless motor has a 750 Watt power and 85 Nm of torque, to bring you quickly to your destination with a fast acceleration and great uphill performance.

Thanks to the efficient power delivery, the battery life is long and it's about up to 80 miles with a single charge.

And that's more, it has been equipped with an efficient Shimano drivetrain and powerful hydraulic brakes, to assure a smooth gear shift and safety in all kinds of terrains.