What’s the difference between a bike computer and a power meter?

Confused about bike tech and whether you need a computer and a power meter? Nik Cook explains how each works


At its simplest, a bike computer shows you how far and how fast you’re going. GPS helped turn it into a sophisticated navigation and training tool, but no matter how many features a bike computer has, it’s still essentially a handlebar-mounted device for displaying data to the rider.


A key bit of data for modern riders is power and, for your bike computer to display that, your bike needs to have a compatible power meter.

Power meters utilise strain gauges to measure a rider’s output. A strain gauge is composed of a silicon or foil pattern mounted on an insulating backing. These are then placed in locations which are subjected to strain, such as the cranks, hub or pedal spindle, and an electrical charge is put through them. Flex on the part containing the gauges cause them to deform, alters their electrical resistance and this can then be measured and expressed as the rider’s power output in watts. Using a data transmission system, typically ANT+ or Bluetooth, this information is then displayed and recorded by your bike computer.

This article appeared in the December 2017 (346) issue of 220 Triathlon. You can subscribe to the magazine here