Ebike Torque Sensors Explained: How Do They Enhance Your Electric Bike Experience?

Depending on factors like your incline, you will require varying degrees of assistance from your ebike. Torque sensors make this variation possible by measuring how hard you are peddling at any given moment, thus determining how much power the motor should supply in that instant. So, how exactly does this helpful technology work?

Ebike torque sensors measure the pressure a rider exerts on the pedal at any time, measured at either the pedal or the chain. This information is sent to the ebike’s motor, which uses the data to determine how much electronic assistance to give the rider at that point, depending on their exertion.

Read on to discover more about how ebike torque sensors work, including the two types of torque sensors, whether a torque sensor is worth it on an ebike, and whether a torque or cadence sensor is better.

What Is A Torque Sensor On An Ebike, And How Does It Work?

The torque sensor can play a fundamental role in making the ebike experience seem more natural and responsive, allowing the bike to seemingly intuitively give you the right amount of assistance as needed. The torque sensor is thus essential to your riding experience, but how exactly does it work?

Torque sensors are incredibly useful, as they allow the bike to give you more assistance when you require it (such as on a steep incline) while not overpowering you when the ride is more easygoing.

How Do The Two Types Of Ebike Torque Sensor Work?

So, what are your torque sensor options, and how do they compare in functioning?

Based on the sensing technologies used, there are mainly two types of e-bike torque sensors:

  • Strain Gauge Torque Sensors are widely used in e-bikes. They work with strain gauges, which are thin, flexible materials that change their electrical resistance when bent under force. These gauges are typically placed on the bike’s crankset, bottom bracket, or rear hub. As the rider pedals, the strain gauge senses the force and turns it into an electrical signal that shows how much force is being used.
  • Torsion Bar Torque Sensors use a metal rod called a torsion bar that twists when force is applied. A sensor (often a hall effect sensor or an optical sensor) detects the twisting motion and measures the angle change. Then, it turns the motion into an electrical signal that represents the force used.

Both types of torque sensors have the same purpose: to measure the force the rider uses and adjust the motor help accordingly. However, the design and use of the sensors can differ between e-bike models and manufacturers. Strain gauge torque sensors are usually more accurate and quick to respond, while torsion bar torque sensors can be more affordable and simpler to include in some e-bike designs.

Torque sensors can also be categorized by their location within the e-bike. There are primarily two main types of e-bike torque sensor placements:

  • Bottom bracket sensors are located in the bottom bracket area, where the crankset and pedals are attached to the bike frame. This placement allows the sensor to directly measure the force applied by the rider on the pedals. Bottom bracket torque sensors are popular because they provide accurate and responsive feedback, resulting in a more natural, bike-like feel when riding.
  • Rear dropout sensors are located in the rear dropout area, where the rear wheel connects to the bike frame. Rear dropout torque sensors measure the force applied to the chain and rear wheel when the rider pedals. While these sensors might not be as accurate or responsive as bottom bracket torque sensors, they can still provide a good riding experience and are often more affordable.

Both bottom bracket and rear dropout torque sensors can use strain gauge or torsion bar sensing technologies. The choice between these two types of torque sensor placements depends on factors such as the e-bike’s design, desired performance, and cost considerations.

Once the torque sensor measures the force applied, it sends an electrical signal to the ebike’s motor controller. The motor controller then uses this information, along with the rider-selected Pedal Assist Setting (PAS), to adjust the motor’s output power, providing the appropriate level of assistance to the rider.

The motor controller provides more assistance to the rider when they exert more force, essentially when they are pedaling harder. This adaptive assistance makes pedaling uphill or in unfavorable weather conditions, such as strong headwinds, easier for the rider. The e-bike “recognizes” when conditions are more challenging and adjusts the level of assistance accordingly.

Is A Torque Sensor Worth It On An Ebike?

There are many benefits to having a torque sensor on your ebike, and experts and enthusiasts alike generally agree that buying one is worth the investment.

As the torque sensor varies the motorized assistance given to the rider, your ebike will respond to your changing energy levels and provide power as needed rather than at a consistent rate.

Thus, equipping your ebike with a torque sensor creates a more natural riding experience than that provided by other sensors on the market, such as a cadence or throttle sensor. Torque sensors are thus a great option for riders who enjoy and are comfortable with the experience of conventional cycling.

Furthermore, by constantly adjusting the amount of power the motor supplies to the rider, having a torque sensor will significantly improve the battery life of your ebike.

Therefore, while an ebike without a torque sensor can still be enjoyable and rewarding, getting a torque sensor is sure to improve your experience on the road, as well as the efficiency with which you use your battery.

Which Is Better: A Torque Or Cadence Sensor?

Torque sensors are not the only ebike sensors available on the market, with the other common option being a cadence sensor. Both of these sensors have strengths and weaknesses and are both effective, although they serve different individual needs.

So, what are the differences between a torque and cadence ebike sensor, and which is better?

Unlike torque sensors, cadence sensors do not measure the pressure exerted on the pedals but rather the speed at which the rider is pedaling. The downside of the form of measurement used by cadence sensors is that the ebike motor will provide the same pedal assistance regardless of how hard the rider is peddling.

This constant assistance can result in a less natural riding experience, as the power supplied by the motor may seem abrupt or inconsistent with the rider’s peddling performance.

Cadence sensors, however, have the benefit of being a lot less expensive than torque sensors and are generally found on entry-level ebikes. They also tend to require less maintenance than torque sensors.

So, while torque sensors are commonly accepted to be better in terms of riding experience, if you are looking for an affordable, entry-level ebike sensor, a cadence sensor can be a good choice too! Ultimately, the correct choice of an ebike sensor for your bike will depend on your financial and physical requirements and needs.

Conclusion

Torque sensors are a valuable addition to any ebike, making the bike more efficient, easier to control, and more fun and natural to ride! Ebike torque sensors measure the force that the rider is applying to the pedals at any given time. This information is sent electronically to the bike’s motor controller, which uses it to determine and vary the amount of electronic assistance required by the rider at that point.

Author

  • Miles Baxter

    Miles Baxter is an engineer with a longstanding love for bicycles, sparked by winning a mountain bike in a childhood lottery. Balancing a keen interest in mechanics with the thrill of biking, his career is a testament to the art of turning wheels and gears into adventures.

    Baxter Miles