PowerTap Joule with PowerCal

Powertrap Joule GPS and power metre

PowerTap Joule with PowerCal
Price R3 695

Powertrap Joule GPS and power metre

In addition to SRAM and Quarq, there’s a new generation of power meters coming onto the market that are either significantly cheaper (such as PowerTap’s PowerCal), or easily portable between bikes (think the Garmin Vector pedal-based system).

Just about anyone who’s serious about their training would benefit from keeping track of their power. “Power meters are great, and can seriously help you improve your fitness, whatever your level,” says Ric Stern of RST Sport Coaching (www.rstsport.com).

The high price of power meters – R30 000 and upwards for SRM cranks and head unit – has been off-putting, though. PowerTap’s Joule power meters bring that price down substantially, using an algorithm (maths-speak for “We aren’t sure how we did it but it works”), a PowerCal heart-rate strap and a handlebar-mounted GPS unit. We have been playing with one for a few months, and it is remarkably accurate when compared with a true meter (maybe not on short efforts; but on longer, sustained rides it is acceptably close).

Use of the Garmin Vector pedal-based system (we tested them in December 2013) makes it easy to run the same power meter on your training and racing bikes, if you are a lucky SOB and have both; and, unlike a hub-based system, you can switch between training and race-day wheels without needing two power meters. But at R24 000-odd, the Garmin system is a lot pricier than the PowerCal.

For many, cost is still a barrier. The prices generally reflect the level of technology as well as the cost of building the device in the US rather than the Far East.

There’s also the question of learning how to use a power meter properly. Put deep-section wheels on your bike and you’ll go faster, whether or not you understand aerodynamics. But it takes a sound grasp of training principles to make sense of the numbers a power meter provides. “It’s no use just using them as an expensive speedo,” says Ric Stern. “While you don’t need to learn everything about them (a coach can help you), it’s useful to have a basic understanding of what the data means.”

Will it make me faster?
Power meters won’t make your bike quicker, but they can make you a faster rider… provided you learn how to interpret the data, or employ a coach.

Powertrap Joule GPS and power metre