BREAKING DRAG

Are CdA-measuring tools the tech of the future? Tech editor Michelle Arthurs-Brennan investigates

- Michelle Arthurs-Brennan

Every decade a new piece of training focused tech is revealed to the cycling community. First it was odometers, then in the 1980s heart rate monitors appeared. In the 1990s it was power meters then GPS devices when we entered the new millennium.

Each new creation is met with questions over the need for such equipment and puzzlement over the complexity of the system and the data it provides. It can take a generation of cyclists to grow up with the technology before it becomes widely adopted.

Eventually, the successful items become commonplace — they’re built into the equipment on our bikes and next thing you know we’re giving each other virtual kudos on social media for the numbers the tech records.

Are coefficient of drag (CdA) measuring tools the latest bit of tech that will become part of our riding? In 20 years’ time will we be unable to imagine training without them, or will we still be looking at this tech with a frown asking, “But does it actually work?”

CDA tells you the size of the front facing silhouette of you and your bike. This is what is hitting the wind and creating 95 per cent of the resistance you are pedalling in order to overcome. It’s what is holding you back.

Tolerances are small — a WorldTour pro will be knocking out around 0.17 in TT mode, while on a road bike without optimisation you might sit at 0.4. The lower the number the better, and it can be brought down by making changes to your position and kit.

There are several methods for measuring CdA. You can check in at a wind tunnel and work with an aerodynamicist, but you won’t be able to guarantee your findings are played out on the road. You can book in with an expert who will use mathematical equations to determine drag from the velodrome, or you can experiment yourself.