Pedal Assist (PAS) or torque sensor
Which type of pedal assistance should you implement?
If you want to ride your e-bike like a bicycle, pedaling but with help, torque sensing is vastly superior. Simple cadence-sensing PAS, as on the BBSHD, simply detects whether or not the pedals are moving, and applies a set amount of power based on which PAS level you've set it to. It's like a cruise control, but in predefined steps, and that only works when you're pedaling or pretending to pedal.
Torque-sensing PAS detects not only whether or not you're pedaling, but also how much effort you're putting in, and it applies power proportional to how much effort you're putting in.
If you enjoy pedaling and/or saving battery then you may be interested in some assistance. In certain locations pedal assistance is also the law. The two most common types are a magnetic cadence PAS sensor and a bottom bracket torque sensor.
Cadence / Magnetic Ring Pedal Assist System (PAS)
pros:
- Inexpensive
- Generally included with hub motor kits
cons:
- Limited by the controllers algorithm, whether that be good or bad is left up to your controllers software
- Measures crank movement instead of force, therefore not as accurate or efficient
Torque sensors (bottom bracket type)
pros:
- More accuracy and efficiency
- Measures the force you apply to it and can distribute proportional force (or more, depending on your software)
- More flexibility, feels more like a bike than a typical PAS system.
cons:
- More expensive
- Requires drilling a hole in the bottom bracket shell for the wire