The best power meters will take the guesswork out of your training and allow you to accurately prepare for races. A power meter that doesn't perform consistently and accurately can throw off a session, causing inadequate training stimulus and subsequently, sub-optimal training. Worse, an under-reading power meter can cause poor pacing strategy in races or FTP testing and longer-term, could lead to overtraining.
The humble power meter has been around in the pro peloton for over 30 years but has only recently become de rigueur among amateur riders wanting to train more clinically and race more effectively, and as data becomes more widely used, the demand for accuracy and consistency is higher than ever.
The trackable, quantifiable and comparable nature of data means the best power meters take the guesswork out of your training and allow you to accurately track your performance by way of power output, cadence, and even kilojoule expenditure.
Over the past several years, power meters have become more affordable thanks to advances in technology and the introduction of a host of new competitors to the fray. There are several types of power meter configurations available which measure power at the rear hub, crank spider, crank arms, bottom bracket or pedals, but choosing the right one comes down to four factors: price, compatibility, accuracy and weight.
Below we explain what to look for in a power meter, along with our roundup of the best.
Skip to: How to choose a power meter
Best power meters
Aesthetically, and mechanically, one of the best units on the market
Weight: 142g, 130BCD (spider only) | Battery life: 200 hours | Battery type: CR2032 | Measurement: Dual-sided | Type: Spider/chainring
Quarq’s latest spider-based masterpiece, the DZero, can be ordered as an individual spider or as a complete crankset in either aluminium or carbon. Not only are the strain gauges located within the spider but it also benefits from a built-in accelerometer to simplify function and boost accuracy — with a variance of only 1.5 per cent. The DZero power meter is compatible with all bottom bracket types and BCD configurations and there’s even a version for Shimano-specific chainrings called DFour. The DZero’s biggest selling point is its ability to measure power from both the left and right leg which helps improve pedal efficiency and power balance.
Stages Power LR Ultegra R8000
Big data for those with a Shimano groupset
Weight: 35g | Battery life: 175+ hours | Battery type: CR2032 | Measurement: Dual-sided | Type: Crank, 165mm, 170mm, 172.5mm, 175mm
Stages Cycling made a name for itself when it dropped the single-leg power meter concept at an amazingly affordable price just a few years ago. Known for continually pushing the boundaries in terms of weight and performance, the Colorado-based firm has taken things up a notch with the introduction of the Stages LR, a dual-sided power meter with generation 3 internals, a boosted ANT+ and Bluetooth signal (6 times stronger than before) and accuracy to a maximum deviation of only 1.5 per cent. Available in three Shimano-only options, Dura-Ace 9100, Ultegra R8000 and 105 R7000, it adds just 35g to the crankset. Even better, Stages introduced a restructuring of its product pricing in early 2020, to the benefit of global customers.
The modular design of Rotor's INspider power meter makes it a sensible investment for the serious cyclist
Weight: 148g | Battery life: 250-300 hours | Battery type: Rechargeable | Measurement: Dual-sided | Type: Spider
The Rotor INspider power meter offers multi-discipline compatibility, and can be seamlessly switched between bikes, granted they all use a Rotor OCP-splined (Optimum Chainring Position) crankset. In terms of compatibility the INspider will play nicely with all crank arm lengths (150-175mm), axle standards (24 and 30mm) and carbon crank arms, not to mention both 1x and 2x chainring configurations.
The INspider uses two paired sets of opposing radial strain gauges which independently measure power at the left and right leg. The upshot of a power meter of this nature is the way in which it harvests data. It can capture up to 200 data points per second, trumping the crank-based alternatives that measure power at one side - no multiplying by two here.
In terms of accuracy, Rotor says there's no real benchmark for comparisons but claims a maximum deviation of only 1-1.5 per cent.
The holy grail of power meters
Weight: from 599g | Battery life: 1400 hours (standard), 100 hours (rechargeable) | Battery type: Rechargeable or Standard | Measurement: Dual-sided | Type: Spider, 110BCD asymmetric
SRM has always been considered the benchmark when it comes to power-meter accuracy - it revolutionised the industry and brought number-crunching to the pro peloton. After producing primarily spider-based power meters for the last three decades, SRM recently launched a more compatible three-piece power meter crank system called the Origin which can accommodate a host of frame/bottom bracket setups.
The SRM Origin power meter comprises crank arms, a spider (110 or 104BCD) and spindle (BB30 and 24mm), and is available in both carbon or aluminium, the latter of which has crank length options of 160-175mm. The carbon version was developed alongside French frame and pedal brand, Look, with a Trilobe pedal insert allowing for adjustable crank lengths of 170, 172.5, and 175mm. SRM claims reliable accuracy levels of 99 per cent.
Accurate and affordable for multiple bike owners
Weight: 296g (actual) | Battery life: 50+ hours | Battery type: Rechargeable | Measurement: Dual-sided | Type: Pedal
Favero Electronics may be a newcomer to the power-meter realm but the Italian manufacturer has taken the fight to PowerTap and Garmin by offering a lighter, cheaper and more accurate power pedal - the Assioma. In fact, they weigh just 148g per pedal, which is significantly less than the Garmin Vectors and PowerTap P2s (216g per pedal).
It's a tidy-looking package - all the sensors and strain gauges are located in a housing next to the pedal body, which measures directly at each axle. Not only does this neat little design cue ensure the Assiomas look like an ordinary pedal and not as chunky and bulky as their rivals, but it also keeps the electronics from getting damaged by falls or impacts, meaning it's easier to maintain down the line. They're also IP67 certified.
Unlike other power meters that harvest data based on the angular velocity of the crank arm through each rotation, the Assioma uses an instantaneous angular velocity (IAV) measuring technique thanks to an on-board gyroscopic sensor. According to Favero, the IAV way of harvesting data is class-leading, with accuracy to a maximum deviation of only one per cent.
The budget-friendly winner
Weight: 9g | Battery life: 100+ hours | Battery type: CR2032 | Measurement: Single-sided, dual-sided | Type: Crank, 165mm, 170mm, 172.5mm, 175mm
Weighing in at a scant 9g, the 4iiii Precision power meter represents the pinnacle of lightweight options on the market. Available as a crank-based left-side-only, or dual-sided unit the company claims it is 99 per cent accurate. The product portfolio comprises just three off-the-shelf options in the form of Shimano Dura-Ace, Ultegra and 105, but you can send your own crank directly to 4iiii Innovations to have a power pod retrofitted, something the company calls a ‘Factory Install’. Prospective buyers should be aware of compatibility issues pertaining to crank clearance at the chain-stays; 4iiii Innovations recommends checking this before ordering.
If you’re looking for a durable and reliable spider-based power meter, look no further
Weight: 172g 130BCD (spider only) | Battery life: 300 hours | Battery type: CR2032 | Measurement: Dual-sided | Type: Spider/chainring
Like Stages Cycling, Power2Max disrupted the industry by bringing power to the people at an affordable price. Owing to its spider-based anatomy, riders are able to choose from myriad crank options depending on budget, something that’s enabled the German company to gain immense traction and market share in a highly competitive space. Power2Max claims its NGeco unit is a dual-sided power meter although it calculates power at the spider and apportions the left/right ratio based on crank position.
However, it does measure both pedal strokes independently, making it superior to those of the single-sided variety that collect data from the left side only.
PowerTap P2 pedals
Best for multiple bike owners
Weight: 402g (actual) | Battery life: 80 hours | Battery type: AAA | Measurement: Dual-sided | Type: Pedal
The PowerTap P2 pedals require no fancy tools for fitment and can be swapped effortlessly between bikes. Not only are they 34g lighter (400g a pair) than before, they also boast a 20-hour battery life improvement over their predecessor (80 hours in total). While they may not appeal to everyone in terms of visual clout (the black P1 pedals are far sexier-looking items) the P2 pedals are appreciably easy to clean and don’t hold much in the way of dirt or grit, regardless of weather conditions and terrain. What makes the them a safe bet is the company’s proven track record in terms of accuracy, durability and reliability. It also helps being owned by cycling industry heavyweight, SRAM.
Proven reliability clad in a smartly designed, robust package
Weight: 170g (340g per pair, actual) | Battery life: 30 hours | Battery type: Rechargeable (lithium-ion) | Measurement: Dual-sided | Type: Pedal
These might not be road bike power meter pedals but they can double up for use on gravel and cyclo-cross bikes, so they're a worthy inclusion on this list. The SRM X-Power pedals represent a ground-up in-house development - the world's first off-road-specific power pedal offering if you will. As such SRM is looking to garner market share in what has become a highly competitive space with rivals such as Stages, Rotor, Power2Max and Quarq dominating the landscape.
The pedals use the tried-and-tested SPD design made popular by Shimano - but with an SRM twist. The colour spread - comprising anodised-lime-green, black or red - will also help those who obsess over colour matching bike equipment. Battery power comes in the form of a lithium-ion supply, with a run time of approximately 30 hours (standby power draw is 2-5 per cent per day). The pedals are charged by way of a single-pin magnetic connector located on the wrench flats - the LED battery charge indicators will flash green once fully charged.
The set-and-forget nature and ease of the installation are truly impressive, and the splash of colour provides a striking alternative to the bland offerings currently on the market.
The complete power meter pedal system
Weight: 320g (Actual) | Battery life: 120 hours | Battery type: LR44/SR44 (x4) or CR1/3N (x2) | Measurement: Dual-sided | Type: Pedal
The Garmin Rally pedals are a system of three pedal bodies with either single or dual power measurement. The range's naming structure is made up of two letters, RK, RS, or XC, followed by the number 100 or 200.
An RK box means you've got a road pedal with a Look Keo compatible cleat. An RS designation means a road pedal using an SPD-SL cleat. The last option is XC and that gets you a dual-sided, two-bolt, SPD-compatible pedal. Next to the letters, you will find either 100 or 200 meaning either single-sided power or double-sided power, respectively.
The big talking point here is the parts that make the Rally pedals work as a power meter live in the spindle. The pedal bodies are interchangeable with an upgrade kit. Whatever you start with is irrelevant other than as a place to start. With that in mind, look at the pedal bodies and you can see the aesthetic design follows the function and the bulk is in the spindle.
With a claimed accuracy of +/- 1 per cent, they're one of the most reliable power meter systems on the market.
How to choose the best power meter
As the name suggests, a power meter is a compact electronic device that calculates power by way of a strain gauge. The strain gauge transduces flex into electrical resistance based on how much strain or torque is applied and multiplies it by the angular velocity (cadence) to calculate power, which is measured in watts. Sounds complicated, right? Thankfully, your cycling computer does all the maths for you, processing the data it receives from the power meter via an ANT+ or Bluetooth connection. That said, not all power meters are created equal – the accuracy and reliability of each unit hinge around a number of complex parameters, the most pertinent being the quality of the materials used in its construction and number of strain gauges fitted. As you can imagine, manufacturing such a device is an intricate process which explains why these components cost as much as they do.
Power meters explained
It’s easy to get overwhelmed by the marketing jargon and complex specification sheets when shopping for a power meter. There are five distinct power meter types based on where it’s fitted to the bicycle, so it’s important to factor in compatibility before making a decision. (Most manufacturers have compatibility charts on their website).
Rear hub power meters
Hub-based power meters are some of the most affordable, reliable and compatible units available. PowerTap is the main protagonist in this segment and its G3 hub has earned a reputation for its hardy and bullet-proof nature. One of the many benefits of using a hub-based system is the convenience of swapping it between bikes. This has become somewhat more complex by new hub standards (quick release vs bolt-thru and disc vs rim), but assuming your wheel will fit both bikes, the power meter can go with it.
Compared to other power meters, the location of a hub-based unit may result in marginally lower power readings owing to drivetrain losses.
Crank arm power meters
Stages Cycling brought affordability and reliability to the market with its left-side crank concept in 2012, and made them cheaper still in 2020. Weighing just 20 grams it redefined the segment with a catalogue comprising a range of crank arms in both aluminium and carbon fibre guise. Since then, 4iiii Precision has jumped on the power bandwagon with its off-the-shelf, left-side Shimano crank arms (Power pods for other models can be retrofitted as a ‘factory installation’). Crank-based power meters are extremely light and affordable but be wary of frame clearance issues on older bikes.
If choosing a left-sided option, the only compatibility consideration you need is to ensure the crank will fit the spindle from the right-side, and that the crank length matches the right.
If choosing a left-right option, you'll just need to ensure the crankset fits your bottom bracket standard.
Bottom bracket power meters
The bottom bracket power meter is not as popular as other designs as it is more difficult to install and isn’t compatible with all bottom bracket systems. But the results don’t lie: Rotor claims its INpower units are 99-per cent accurate (variance of 1 per cent). Another benefit is that the power meter’s innards, battery and electronics are housed within the bottom bracket for added protection and weight balance.
Pedal power meters
Not only are power pedals easy to swap between bikes but the plug-and-play nature nullifies the need for complex fitting procedures. Available in two distinct guises: single- or dual-sided, it’s the latter which can independently measure left-right balance as well as calculate pedal smoothness and efficiency. The only pitfall stems from the extra weight of the electronics, strain gauge and battery pack located within the pedal assembly. PowerTap, Look, Garmin and Favero are the chief players in this segment with little between them in terms of performance and reliability.
They can even be swapped onto an indoor or gym bike for some Zwift action should you be away from home without a bike.
Crank spider power meters
Spider-based power meters rose to prominence in the late 1980s with SRM who pioneered the concept. Available in various shapes and sizes these power meters are compatible with most bottom bracket and chainring BCD patterns and can be purchased individually as a spider or complete chainset. Leading products here come from brands such as SRM, Quarq and Power2Max, each of which offers varying price points, weights and power-measuring functionality.
The compatibility here can be somewhat daunting, but manufacturers simplify things by offering spider-based power meters based upon the make-model of the crank you're using. The only thing to then consider is chainring BCD; you'll generally have 4- or 5- bolt configuration, and the bolt-circle-diameter will generally be written on your current chainrings.
Aaron is Cyclingnews' tech editor. Born and raised in South Africa he completed his BA honours at the University of Cape Town before embarking on a career in journalism. As the former gear and digital editor of Bicycling magazine and associate editor of TopCar, he's been writing about bikes and anything with wheels for the past 16 years. A competitive racer and Stravaholic, he’s twice ridden the Cape Epic and completed the Haute Route Alps. When not riding, racing or testing bicycles in and around the UK's Surrey Hills where he now lives, he's writing about them for Cyclingnews and Bike Perfect.
Rides: Cannondale Supersix Evo Dura Ace Rim, Cannondale Supersix Evo Disc, Trek Procaliber 9.9 MTB
Thank you for signing up to Cycling News. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.