Polar CS400 heart rate monitor review

Polar’s mid-range, bike-mounted computer and HRM, the CS400 is a curate’s egg that needs time and effort learning its quirks to get the best out of it.

The CS400 is small and light, and can be mounted either on the bar or, as we prefer, on the stem.

The buttons are large and easy to hit, and the read-out is clear and can be read while bumping along. Its overall shape is very appealing, too.

However, we were disappointed at how user-unfriendly the operating system was. Inputting the setting is relatively straightforward, but toggling through the options to arrive at your target display is not.

We found it unreliable too. We’ve wiggled the fork/wheel sensors to within the recommended 4mm range, moved the head unit to see if the signal was being blocked by the stem, but to no avail. Sometimes we get a reading, sometimes not.