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

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.

• Bike computer: what to look for
• Training: the 3 most valuable metrics triathletes should measure
• How to interpret data to see if your performance is improving

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

• Power meters: Do I really need one for triathlon?
• Bike power meters for triathletes: what to know
• Should you trust your bike power meter?
• The best bike computers
• Garmin Edge bike computers: buyer’s guide to all the models

220 Triathlon Team Journalists, reviewers, coaches and athletes

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The 220 Triathlon team is made up of vastly experienced athletes, sports journalists, kit reviewers and coaches. In short, what we don't know about multisport frankly isn't worth knowing! Saying that, we love expanding our sporting knowledge and increasing our expertise in this phenomenal sport.