What is a Torque Sensor on an ebike?

Confused by ebike jargon? You’re not alone.

If you’re perplexed by the words used in electric bike specifications, then you’ve come to the right place. Today, we’re going to look at the phrase “Torque Sensor” to see what it means on ebikes (and why it’s a useful thing to look out for when you’re purchasing an e-bike).

The 2 types of sensor on an ebike

Many electric bikes are known as “Pedal assist”, which means that the electric motor will deliver power to the wheels to help push you along as you pedal. The alternative to pedal-assist is a throttle ebike and these give electric power whenever you push the throttle.

It’s worth bearing in mind that pedal-assist will ONLY give power whilst you’re pedaling – stop turning the pedals and the motor stops supplying you with power.

Pedal-assist ebikes use a sensor to determine whether or not you’re pedaling and these come in two different flavors: cadence and torque.

Let’s look at the differences between the two so we can understand what “torque sensor” means.

torque sensor vs cadence sensor on an ebike

Cadence sensor

A cadence sensor has one job and one job only: it checks whether the pedals are being turned.

If they are, it will engage the motor and deliver a boost of power to help you pedal along.

On the other hand, if the cadence sensor doesn’t detect that the pedals are being turned, then it either won’t engage the motor, or it will turn the motor assistance off.

Cadence are the original type of sensor used on ebikes and are still fitted on the majority of bikes currently being sold. And with good reason – they’re a much cheaper component to add to the specification list.

That means that e-bikes with cadence sensors can usually be made available for purchase at a lower price and will therefore be more affordable.

Unfortunately, there’s a downside to cadence sensors.

Because of their ON/OFF nature, they can give a somewhat more jerky feeling ride than a torque sensor:

  • As soon as you stop pedalling, the motor turns off
  • Start pedalling again and the motor kicks back in instantly

In practice, this is a minor irritation – you still get the power when you need it after all. Plus, many ebikes with cadence sensors have a series of power levels that you can choose from as you pedal along.

Torque sensors, however, take the experience up to another level.

Torque sensor

Torque sensors do two jobs on an ebike:

Firstly, they check that the pedals are being turned. If they are, then the motor will be engaged and start to deliver pedal-assist power.

So far, so similar to a cadence sensor.

But, what torque sensors then do, is to check how HARD you’re having to pedal:

Pushing harder on the pedals? Then the torque sensor knows you need more power and tells the motor to turn it up a notch.

Pushing lighter on the pedals? Then the torque sensor knows that you don’t need so much power and lets the motor know it can kick back and take it a little easier.

So, what does this feel like when you’re riding an electric bike with a torque sensor?

Smooth power.

Unlike the cadence sensor, which can feel a little jerky to ride on – the power is either ON or it’s OFF with no ‘inbetween’ – ebikes with torque sensors can feel much smoother.

Closer to the feeling of riding a regular bike…albeit with a big dose of extra power to whizz you along!

I’m a bit of a nerd, so here’s an impression of what this might feel like in graph form:

The blue ‘torque sensor’ line is a smooth curve, whereas the red ‘cadence sensor’ line is jerky.

Power graph: torque sensor vs cadence sensor

Now, torque sensors are great at giving a much smoother riding experience but, because they’re a more complex piece of tech than a cadence sensor, they can add to the price of an ebike.

Conclusion

To sum up, torque sensors measure how hard you’re having to pedal on your ebike and adjust the motor power levels accordingly.

Most ebikes have cadence sensors which just check whether you’re pedaling or not. If you are, then the motor kicks in to help out. These e-bikes can feel a little jerkier to ride but they’re cheaper to purchase.

Electric bikes with torque sensors will give a smoother power output and this gives more of the feeling of riding a regular bike (but with superhero legs!) The downside is that they’re more expensive to purchase as the torque sensor tech is newer and fancier than cadence.

The choice is yours, but whichever type of ebike you choose I’m certain you’ll love riding on it.

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