A cadence or torque sensor tells the e-bike's Pedal Assist System (PAS) when to engage the motor and propel the e-bike forward. Although cadence sensors, and torque sensors are available for almost any e-bike conversion kit, each sensor type affects the performance and ride of the e-bike.
So what's the difference between a cadence sensor and a torque sensor on an e-bike? A common response from the bicycle manufacturing industry is that a cadence sensor determines if you are pedaling, while a torque sensor measures your pedaling.
CADENCE SENSORS
Most Cadence-based pedal assist systems can engage the electric bike's motor when the rider starts pedaling. To explain this simply, when a sensor detects any kind of movement of the pedals (when PAS is on), it sends a signal to the electric motor to start working. The motor then specifies a certain amount of power to move the rider forward.
The rider's effort for the pedals and the selected level of pedal assist will affect the amount of power contributed by the motor. On Cadence-based pedal assist systems, the manufacturer typically has pre-set speeds at each level of pedal assist. As the rider's pedal cadence increases, the motor will continue to output until a predefined threshold is reached and the necessary conditions are maintained over the various terrains, gear levels and pedal cadence being performed by the rider.
In brief, as the rider's pedal speed increases, the pedal assist will increase the motor output; as the rider's pedal speed decreases, the PAS will reduce the output of the motor to propel the rider forward.
ADVANTAGES OF CADENCE SENSORS
- Ease of use
One of the biggest advantages of riding an ebike with a cadence sensor is the ease of use. EBIKES based on cadence sensors require relatively light pressure on the pedals to activate the motor. Thus, the rider can pedal with minimal force, but the motor can still be turned on, albeit at a different level. This makes Cadence-based Ebikes the perfect choice for recreational riders or riders with physical limitations who want a relaxed ride.
- Consistent power
The Cadence-based system can be switched on and off like "ON" and "OFF". In other words, the rider will get help at a preset speed when pedaling and stop getting help when stopping pedaling. Given this, it is usually possible to ensure that Ebikes with cadence sensors provide riders with consistent power and consistent help when they need it; they don't need to put in extra effort. Whether a rider is climbing a hill, wants to cruise around at a minimum speed, or wants to pick up speed faster, Cadence sensors will always prescribe a consistent set of power.
DISADVANTAGES OF CADENCE SENSORS
- The potential for a smaller range
Range is an important factor when considering which e-bike is best for you, and there are multiple variables that will ultimately affect the estimated range of an e-bike versus the actual range. Widespread use of pedal frequency based PAS, especially at higher levels for longer periods of time, will use a lot of the e-bike's battery power to start the motor. Thus, affecting how far a single charge can go.
- Give and take is not equal
This is ultimately subjective, but depending on the rider's activity level, preferences, and riding needs, a cadence-based e-bike may feel as if they are not doing enough work. Since the sensors communicate to engage the motor any time they sense movement on the pedals, riders may feel like they are getting too much PAS and they are putting in very little and getting very little exercise. Or maybe the rider puts in a lot of effort on a climb but doesn't gain as much speed as expected. But for the recreational rider or the physically challenged rider, maybe this is exactly what they are looking for: an absolute riding experience that requires less effort!
Torque sensor
A torque sensor uses a precision strain gauge to measure how hard the rider is pedaling. The torque sensor measures the force applied to the pedals by the rider and then determines how much power the motor should deliver to the e-bike. The torque sensor makes these adjustments in real time, increasing or decreasing the output of the motor in concert with the pedal force applied by the rider. In other words, the torque sensor is working on and amplifying each of your inputs.
In a nutshell, the harder you pedal, the more output the motor provides, up to a preset limit for a given PAS level. The less you pedal, the more the motor will meet you where you are and output less power.
ADVANTAGES OF TORQUE SENSOR
- A more natural and intuitive ride
Riding may feel more intuitive because the torque sensor adjusts the motor's assist level to match the rider's pedaling effort. The rider does not suddenly gain power when changing PAS levels, as the torque sensor informs when power is provided and does so gradually and dynamically. In many cases, the torque sensor PAS can mirror the feel of riding a regular bike because the rider can connect directly to the motor.
- Higher range
Since the torque-based PAS system does not produce a predetermined amount of output at any given PAS level, riders can save battery power and ride farther. Because its motor simply helps the rider, depending on how much effort they put in, torque-based e-bikes don't over-consume energy. Instead, they will only provide what is needed to make the rider feel like they are powering their e-bike, rather than their e-bike doing the heavy errands for them entirely. Ultimately, giving them better control of their ride, their e-bike and their experience.
DISADVANTAGES OF TORQUE SENSORS
- Harder to reach top speed
Riders get the results they want to achieve with torque sensors. Therefore, to reach higher PAS speeds, they need to put more work into pedaling a torque-based system than a pedaling frequency-based system, which will immediately output at a higher set speed, allowing the rider to experience faster speeds. In addition, once an e-bike with a torque sensor reaches top speed, maintaining top speed also requires more sustained pedal power.
Conclusion
Ultimately, understanding torque and pedal sensors is not a question of "which is better? It's a question of "Which is better for me?" Pedal sensor PAS technology has become a common staple in the e-bikes riders are looking for, giving them the freedom to put in as little effort as possible without losing power. On the other hand, torque sensor PAS technology takes the rider's input and amplifies it to provide a more natural and intuitive riding experience.
Both types of e-bikes will ultimately provide riders with what they are looking for: battery powered assistance while riding. The question to ask yourself is, how much or how little work do you want to put into getting that assistance? If you want the option to increase pedaling power when you need it, but have the flexibility to rely solely on high and powerful speeds, try riding an e-bike with a pedaling sensor test. Or, if you want your e-bike to simply amplify your efforts, consider test riding an e-bike equipped with a torque sensor!
