In just a few years, power meters have moved from being pro-only equipment to affordable training aids for amateur racers and keen recreational riders. When used properly, a power meter gives you potent information that can vastly improve your training and pacing.
Compared to a heart-rate monitor, a power meter delivers objective measurement of the work you’re doing, regardless of how your body feels about it. Heart rate, by contrast, is greatly influenced by fatigue, temperature, adrenaline and that caffeine gel you just sucked down. Heart rate also responds very slowly: do a short sprint with lots of power, and your heart rate will barely rise before you finish; coast over the top of a hill that you just hammered up, and your power drops to zero yet your heart rate continues soaring.
A power meter helps you to define your training zones and then train in them correctly. Power meters are also the perfect tool for pacing your effort, whether on a 10-mile time trial or a 100-mile sportive.
For this feature, we tested seven meters, including the two pedal-based systems from Garmin and PowerTap, the revised version of the Stages crank (the device that arguably kickstarted the affordable power meter market), the new Infocrank and the standard-setting SRM.
More than 80 rides went into this test, and for each one we ran three meters at once, with three identically configured Garmins on the bars to record the data. Using one meter on its own makes it impossible to tell if it’s accurate or not; two is better but you won’t know which is reading incorrectly if the shift is small. With three, you can see when one is out but the other two are in agreement. Of course, it’s possible that they could all be having a bad day but we’ve done our best to eliminate that by doing so many rides.
Be sure to check out the chart at the bottom of this feature that details the weight, L/R measurement,
- Strain Gauges: You can’t see them but these thin strips of metal are bonded in place to a structural part of the meter. As force is applied to, say, the crank, it deforms by a microscopic amount and the strain gauges deform with it, allowing a calculation of force, and ultimately power.
- Compatibility: Power meters can be built into pedals, cranks and hubs, and your bike(s) may influence your choice. For instance, the Stages isn’t yet offered for Campagnolo; the Infocrank and Rotor only come with a 30mm spindle; both the Garmin and PowerTap pedal systems dictate that you use Look Keo cleats.
- Weight: The lightest of these systems adds just 20g to your bike; the heaviest nearly 300g. If weight really matters (ie, you have a sub-7kg bike, sub-7% body fat) then weight should be part of your decision, but otherwise we think it is secondary to performance, as with most things.
- Battery: Nearly every meter now has a user-replaceable battery, usually a coin type. You should travel with spares because Murphy’s Law dictates the battery will run out on day one of that big trip to a race or vacation.
- Manual Zero Offset: This is a simple pre-ride calibration check that most power meter companies say you should do. A few say it isn’t necessary but it’s still good practice. If you keep your bike indoors and it’s cold out you may also need to repeat the calibration 10 minutes into your ride.
The best power meters of 2016
Quarq Elsa RS
- Pros: Accuracy, consistency, simplicity, value
- Cons: No Bluetooth
Stages Dura-Ace 9000
- Pro: Lightest on test, simple, consistent, now tougher, good price
- Con: Limitations of left-only
SRM Power Meter
- Pros: Reliability, consistency, battery life, crank options
- Cons: Very expensive, no DIY battery swap, no analysis, requires frame magnet
- Pros: Accuracy, consistency
- Cons: TA rings, chunky looks
Garmin Vector 2
- Pros: Transferability, light, robust, extra analysis
- Cons: Not the best consistency and accuracy, dictates Look cleats
- Pros: Accurate, consistent, fits any bike
- Cons: Obvious limitations of wheel choice
- Pros: Easiest to transfer, value
- Cons: Weight, cornering clearance, some sketchy data, no left-only option
How they compare
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