What to Know Before Buying a Power Meter

There are several different ways to mount a power meter to a bike, each with its own set of advantages and disadvantages. There is no right way, or even a best way, to mount one: It's all about what works for your situation.

The three basic styles of power meter are pedal-based, crank-based, and hub-(wheel)-based. We’ll explore these in detail over the next few slides. 

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Note: Power meters measure the distance between the pedals and rear axle, an area that’s rapidly fluctuating. Drivetrain, brake, and axle standards are rapidly changing these days, which makes investing in a power meter feel like a bit of a gamble. Will the power meter hub you buy today work on the bike you buy next year? Unfortunately, you just can’t know. Regardless, with regular use, you can still get valuable training data once you do get set up.

Advantages

• Leaves your drivetrain alone.
• Allows wheel swaps for different events or situations.
• Dual-sided versions offer a left/right balance, as well as a pedal force and stroke analysis.
• Somewhat easy to move from bike to bike.

     RELATED: The Beginner's Guide to Riding with Power

Disadvantages

• Not available in all pedal systems (notably Shimano or Speedplay)
• No mountain bike options.

Examples: Garmin Vector 2 (pictured) and 2S, Look Keo Power, and PowerTap P1.

(This power meter category includes chainring-, spider-, and crank arm-mounted systems)

Advantages

• Available in a range of options to fit different bikes and uses (road, mountain, track, BMX, etc).
• Allows the use of your favored pedal system.
• Allows wheel swapping.

Disadvantages

• The most difficult type to swap from bike to bike.
• Bottom Bracket standards may make some crank and frame combinations incompatible.
• For Powertap C1 rings, there's limited crank and spider compatibility.

Examples: Pioneer, SRM, Quarq, Power2Max, Verve Infocrank, Rotor INpower, Powertap C1 chainrings (pictured), and Stages.

Advantages

• Easiest to install and move from bike to bike (in rim-brake, quick-release format).
• PowerTap hubs automatically hit zero when coasting.
• Leaves the drivetrain alone.
• Allows you to use a favored pedal system.

     RELATED: 6 Popular Power Meters, Explained

Disadvantages

• Not favorable if you have multiple wheelsets for training, racing, or environmental conditions (unless every wheelset has a power meter, which is expensive).
• Rim and wheel brands are limited.

Examples: PowerTap G3 (pictured) and GS hubs.

A single-sided power meter measures the power of only one leg, usually the left. To provide your complete power, it doubles the power on the measured side. This assumes perfect symmetry, but most people are not perfectly balanced and consistent.

Advantages

• Usually the simplest, cheapest, and lightest way to get into training with power.

Disadvantages

• This form of measurement does not provide the precision or accuracy of a complete or dual-sided power meter. For most cyclists this may not matter, but for high-level training and racing, single-sided meters don’t provide a complete enough picture.

Recommended: Stages power meters. Stages offers a range of arms for many different applications—road, mountain, track, and cyclocross—offering the greatest chance for compatibility (you just swap your existing left arm for one with a Stages unit installed). Early units were finicky, but later versions and firmware updates have addressed most known issues.

Examples: Rotor INpower (crank), Garmin Vector 2S (pedal), Pioneer LT (crank), Look Keo Power Essential (pedal), and Stages Dura-Ace 9000 left crank arm (pictured). 

Complimentary head unit: Your smartphone running the Wahoo Fitness App (may need ANT+ key).

Complementary analysis: Strava Premium ($59/year).

Complete power uses a single meter to measure power from both legs. This is probably the kind you’ve seen most; SRM’s power meter, which was built into a crank’s spider, is considered the originator of the power meter category, and the company’s products are still regarded highly. 

     RELATED: A Guide to Power Meter Metrics

Advantages

• It provides a complete power picture and can be used for high-level training, racing, and when working with a coach.
• Recent competition has driven down prices for these meters.
• There are several formats and options available.

Disadvantages

• These are generally more expensive than single-sided power meters, while less feature-filled than dual-sided models. 

Recommended: PowerTap G3. A wheelset with a Powertap hub is the easiest to install, and the easiest to switch to a different bike. It automatically zeros when coasting, which helps ensure precision and accuracy without any effort on the rider’s part. (In my experience, the PowerTap hubs have proven very reliable and the easiest of any power meter to live with.)

Other examples: SRM (cranks, pictured), Quarq (cranks), PowerTap C1 (chainrings), and Power2max (cranks).

Complimentary head unit: Garmin Edge 520 ($300).

Complementary analysis: Today’s Plan Premium with unlimited training plans ($150/year).

Double-sided power systems consist of two independent power meters, with one for each leg. This allows the system to gather more information, and potentially offer more feedback to the rider. However, the information obtained from double-sided power meters isn’t always useful. “With regards to right-left pedal stroke analysis, I think the sport science community is still trying to figure out what to do with that data,” says Frank Overton of FasCat Coaching. 

Advantages

• They have all the advantages of a complete power meter, plus additional detail and information.
• Left/right power information is helpful when recovering from a lower-body injury.

Disadvantages:

• Two power meters means potentially double the risk of problems.
• These systems equire more batteries and also weigh more.
• The added information and features may not offer much benefit.
• They cost more than most other styles of power meters.

Recommended: Pioneer PM-90 Power Meter. Pioneer mounts their system on Shimano Dura-Ace cranks, but they also work with SRAM and Campagnolo 11-speed drivetrains. Besides being the best cranks (with the best-shifting rings) on Earth in my opinion, they use a 24mm axle that can be adapted to almost any bottom bracket standard, and are offered in many lengths (165, 167.5, 170. 172.5, 175, 177.5, and 180mm). In pedaling monitor mode, which requires Pioneer’s head unit, the system provides a higher sampling rate than ANT+ and provides a level of detail not found elsewhere—this is why you would buy a dual-sided power meter over a complete power meter. The same system is offered on a Shimano Ultegra crank, which is heavier and not offered in as many lengths. The system works in single or dual mode with ANT+ head units as well, but does not provide as much information as when paired to Pioneer’s head unit.

Other examples: Garmin Vector 2 (pedals), Verve Infocrank (crank), PowerTap P1 (pedals), and Look Keo Power (pedals, pictured).

Complimentary head unit: Pioneer CA500 ($300).

Complementary analysis: A cycling coach! (price varies).

Like DVD players (remember those?), power meters were astronomically expensive at first, but prices have dropped over time, especially during the past few years.

An important thing to consider: Power meters are a rapidly evolving category of training technology. As with smartphones, as soon as you buy a particular model, a new one will come out that’s lighter, cheaper, and more powerful—but if you want to ride with power, you have to jump on the train sometime. Just know it’s never going to stop. 

Least expensive options: Single-sided power meter: Stages crank arm; complete power meter: Power2Max crankset; dual-sided power meter: PowerTap P1 pedals (pictured).

The table below lists the most common power meters and their prices at press time.