Sleek, lightweight and easy to use, PowerTap's Joule GPS is packed with valuable data to maximize your training. With 35 different field metrics, ANT+ compatibility, and three "dashboard" screens, you can easily keep track of power, elevation gain, distance, heart rate, TSS, cadence — the list goes on. Being able to view six customized metrics plus two sub-fields on each dashboard reduces stress and time spent changing screens. Navigating the dashboards and starting/stopping intervals is easy with a few simple, easy-to-hit rubberized buttons, and because Joule GPS keeps historical records for up to a year, you can compare current rides to past performances, making it an invaluable tool for tracking progress on the go. Plus having GPS focuses your energy on the ride, taking the guesswork out of staying on course when exploring new routes, and allowing you to map all your rides back at home.
By now you've probably seen friends riding with fancier-than-normal computers and strange new hubs, cranks or pedals on their bikes and found out they're riding with power meters. You may also have overheard cyclists and coaches talking of "power" and "watts." Or maybe you've read of the amazing wattage output of professional cyclists.
We're not surprised. Power measurement is the most objective, reliable measurement of cycling output, and we're here to explain how it works and help you decide if you should join the most exciting revolution in cycling since shifting brake levers.
It also has a lag in catching up to the muscular effort of pedaling. And, while heart rate increases at a rate proportional to pedal power in a controlled lab environment, it rarely does so on the road or trail. Heart rate also has high susceptibility to temperature, fatigue, altitude, caffeine intake, time of day and more, making it an imprecise measure of performance on a given day and a limited tool for comparing multiple workouts.
|Watts Are Better
Watts are better for a number of reasons, including:
Watts are objective, not dependent on the varying factors of your body or the weather. If you held 305 watts for 30 minutes on April 8, and then you churned out 318 watts for a 30-minute period a month later, you know you are improving.
Once you have this number you can compare it to get an apples-to-apples comparison and see how you're doing related to other cyclists (chart). And this will give you an idea what level you need to get to to improve.
Finally, you'll be able to track your fitness and improvement over a wide array of new levels. If you've enjoyed measuring your average speed on your favorite courses, you'll love being able to measure effort, calories, time in various zones, the intensity factor of the ride and much more.
TSS takes IF into account to provide an even better big-picture measurement of training stress. By taking IF and duration into account, TSS can be used to quantify your overall training load. By then gradually increasing TSS for several weeks and dropping it during rest weeks, you can pinpoint overload training like never before. Or, if serious training isn't your goal, you'll be able to gauge fatigue like never before. If you have trouble sleeping or find yourself snapping at your relatives, a quick check of TSS will show you if overtraining is to blame.
3 Customizable Dashboards
Battery Level Indicator (Sensors, Joule GPS)
Cadence (Current, Average, Maximum)
Distance Remaining in Workout
Distance to Next Route Point
Distance to Ride Partner
Heading to Next Route Point
Heart Rate (Current, Average, Maximum)
Heart Rate Zone
Intensity Factor (IF)
Intervals Summary Screen
Kilojoules per Hour
Normalize Power (NP)
Peak Power (5 second, 5 minute, 20 minute)
Pedal Balance (Current, Average)
Percent Grade (Current, Average)
Power (Current, Average, Maximum)
Power Zone (Current, Average)
Speed (Current, Average, Maximum)
Surge Count (W/Kg)
Time of Day
Time Remaining in Workout
Time to Ride Partner
Training Stress Score (TSS)
Watts per Kilogram (Current, Average, Maximum)
|Joule GPS w/PowerCal heart rate strap||012527010929||30202|