# How to fit a cadence sensor to a spin bike

Source: https://rowandspin.co.uk/blog/how-to-fit-a-cadence-sensor
Published: 2026-10-12
Publisher: Row and Spin

**In short:** A cadence sensor is a small device that straps or sticks to the crank arm or your shoe and sends your pedalling rate (RPM) to an app by Bluetooth or ANT+. Clean the crank, fix the sensor on the inside of the crank arm with the mount supplied, wake it by pedalling, then pair it in the app. It measures cadence only, not watts.

Many spin bikes have no console or only a basic one, which makes it hard to follow class cues such as "ride at 90 RPM". A cadence sensor is a cheap and simple fix. It counts your pedal revolutions and sends the figure to your phone, tablet or watch. This guide explains how the sensors work, how to fit one, how to pair it with common apps and what it will not tell you, so you know whether it solves your problem or whether you need a bike with built-in data.

## How cadence sensors work

Most modern cadence sensors use an accelerometer. They detect each turn of the crank by its movement, so they need no magnet. You fix the sensor to the crank arm or to your shoe, and it reports revolutions per minute.

Older designs use a magnet on the crank and a sensor on the frame, like the sensors inside many exercise bike consoles. They work, but they are fiddlier to line up. For a spin bike, a magnetless sensor is the easier choice.

## Bluetooth or ANT+?

Many sensors support both. **Bluetooth** connects directly to phones and tablets, which suits most app users. **ANT+** is common on sports watches and bike computers and can connect to several devices at once. If the sensor supports both, you can use whichever your device prefers.

Check that your chosen app supports external cadence sensors. Most training apps do, including the Peloton app, which can show cadence from a compatible Bluetooth sensor, but features vary by device and platform.

## Fitting the sensor

Some sensors can also clip to your shoe laces. That works on any bike, including bikes where the crank is covered, but it reads your foot rather than the crank, so make sure it is firmly attached.

1. Clean the inside face of the left or right crank arm with a damp cloth and dry it.
2. Fit the sensor in its rubber mount or holder as the instructions show.
3. Place it on the inside of the crank arm, near the pedal end, so it does not touch the frame when the crank turns.
4. Secure it with the band or adhesive pad supplied.
5. Turn the pedals slowly to check it clears the frame and your foot.
6. Pedal for a few seconds to wake it up.

Note: Stop the flywheel before fitting anything near the crank. On a fixed-flywheel bike, the pedals keep turning until the flywheel stops.

## Pairing with an app

Open the app's sensor or device settings and search for a cadence sensor while you turn the pedals. The sensor goes to sleep after a short time without movement, so keep pedalling while pairing. Once it appears, select it and save.

If the sensor will not appear, check that another app or device is not already connected to it over Bluetooth, and that the battery is fresh. Coin cell batteries are common and easy to replace.

## What a cadence sensor cannot tell you

A cadence sensor measures how fast you pedal, not how hard. It cannot measure power in watts, because watts depend on resistance as well as speed. On a spin bike with a manual resistance knob, no app can know how much resistance you have set.

That matters for Zwift and similar apps, which need power or speed data to move your rider realistically. For these, a bike that reports watts over Bluetooth is a better choice. Our guides to [using Zwift or the Peloton app on any bike](https://rowandspin.co.uk/blog/using-zwift-or-peloton-app-on-any-bike) and [cycling power zones](https://rowandspin.co.uk/blog/cycling-power-zones-explained) explain why power matters.

| Data | Cadence sensor | Bike with power output |
| --- | --- | --- |
| Cadence (RPM) | Yes | Yes |
| Watts | No | Yes |
| Works with any bike | Yes | Built in |
| Suits class cues | Yes | Yes |
| Suits Zwift and power zones | Limited | Yes |

General capabilities; check app support

## When to choose a smarter bike

If you want watts, automatic logging and full app support, look for a bike whose listing mentions Bluetooth FTMS, power in watts or support for Zwift and Kinomap. Several bikes in our [best Peloton alternative bikes](https://rowandspin.co.uk/best/best-peloton-alternative-bike) and [best spin bikes](https://rowandspin.co.uk/best/best-spin-bike-uk) guides do this.

If you just want to hit cadence targets in classes, a cadence sensor on your current bike does the job well.

[See bikes with built-in data](https://rowandspin.co.uk/best/best-peloton-alternative-bike)

## Frequently asked questions

**Does a cadence sensor work on any exercise bike?** Yes, as long as there is room to fit it on the crank, or you clip it to your shoe.

**Can a cadence sensor measure watts?** No. It measures pedalling rate only. Watts need a power meter or a bike that reports power.

**Will a cadence sensor work with the Peloton app?** The Peloton app can show cadence from compatible Bluetooth sensors on many devices. Check Peloton's current support notes.

**How long does the battery last?** It depends on the model and use. Most use a replaceable coin cell battery.

## Buying guides on this topic

- https://rowandspin.co.uk/best/best-spin-bike-uk
- https://rowandspin.co.uk/best/best-peloton-alternative-bike
- https://rowandspin.co.uk/best/best-spin-bike-under-500