Torque Sensors vs Cadence Sensors: The Differences

The short version: a cadence sensor reads how fast you turn the pedals, and a torque sensor reads how hard you push them.¹

Speed or force, or both. That's the whole split.¹

Side by side

The table's last row comes from one source. Speed is measured at the crank or another suitable location. Force is measured near the crankset, or at hub motor axles.²

Placement varies. Don't assume your bike matches the table. The table is a summary of two sources, not a description of any one bike. If your bike's listing doesn't say which kind of sensor it has, ask the maker or read the manual before you decide anything. A short question to the maker saves guessing, and the answer is worth keeping.

Pedal turns and road speed

Pedal turns and road speed aren't the same number. One source says the same cadence can produce different speeds and power outputs, depending on the selected gear.³

The sources don't describe how any one bike uses its sensor, so check your maker's description. They also don't say whether a force sensor reports crank speed too.

Both at once

A design doesn't have to choose. Measurement of both force and speed is one of the listed ways to control the motor.²

Some models also allow manual switching from torque to speed control.² If a bike advertises that, ask the maker what each mode does.

What the sources say about weaknesses

One source covers simple magnet-and-switch designs of the kind found on bicycle computers. It calls them slow and says they may give jerky motion.²

Keep that in proportion, and read it as a note about one design rather than a ranking of sensor types. That comment is about one kind of speed sensing. It isn't a verdict on every cadence sensor. And the source doesn't say torque sensors never have problems of their own.

What to ask before you buy

• Which does the bike measure: force, speed, or both?
• Where is the sensor, and is it part of the drive unit?
• Does the maker's manual describe how assist responds?

The answers sit in the maker's manual or spec sheet, not in a listing's headline. For basics, see what a sensor does, cadence sensors and torque sensors.

Don't try to swap or open a sensor yourself. Follow the manual for your own model, or use a shop that services e-bikes.