No tool is more helpful than a power meter for serious training. Other metrics are changeable: Speed varies with terrain, and heart rate can change depending on temperature, time of day or strength of pre-rideespresso. But power meters deliver an absolute and immediate measure, in watts, of the force going into the pedals.
CycleOps’ new Joule 2.0 takes wireless readings from a sensor mounted in the rear hub (sold separately) and relays them to a handlebar-mounted head, which converts the data into speed, time, distance, cadence (pedal RPMs), elevation and watts. It then combines those numbers in various ways to come up with some incredibly complex metrics. It also has functions for programmed workouts and for comparing your current ride data to historical averages to measure progress.
OK, this thing has a lot of numbers. Understanding what they mean and how best to make use of them takes time — try a couple of hours with the manual and a lot of test rides. But once we understood what we were looking at, navigation with the two rubberized buttons and small joystick was remarkably easy, even while riding. Syncing with the included software was also simple, though making sense of the various graphs takes more homework.
Our major gripe with the design is that the data screen is recessed too deep inside the computer body. In anything other than midday sun, the sides of the body throw shadows across the screen that we found to be a constant, if minor, annoyance.
If you’ve never entered a bike race and never plan to, the Joule is expensive and complex overkill. But if you’re a gram-counting roadie, it will become as indispensable as leg razors and Spandex.