Beginner’s Guide to Buying a Power Meter
New to power meters? You came to the right place! We wrote this Beginner’s Guide to Buying a Power Meter just for you. This guide is specifically designed for those new to power who want to get up to speed fast and contains everything you need to know before buying a power meter. What a power meter is, how they work, the different types, etc. Oh, and of course how you’ll benefit from using one! After reading this guide, you’ll know all the basics and will be well on your way to getting powered up!
Please note that this guide is geared towards cyclists that are new to power. Our goal here is to hit all the important points, without going too deep into the weeds. After reading this guide, if you want to take your power meter knowledge to the next level, we recommend you check out our Power Central. We have loads of power meter related content and resources there. Ok, let’s get started!
You can click on any topic above to jump straight there.
1. What is a Power Meter?
A power meter is an electronic device that measures the power, or torque, the rider generates when they turn the pedals. A power meter literally meters (hence the term ‘power meter’) your power. Power, measured in watts, is a measurement of the work you do on the bike and is the most accurate way to measure and gauge your effort.
There are several different types of power meters, depending where on the bike the power meter is located. For example, you can buy a crank-based power meter, where the power sensors and electronics are built into the crank. Or you can buy a pedal-based power meter where the sensors and electronics are located in the pedals. You can put a power meter on virtually any bike – road, mountain, track, cyclocross, BMX, etc.
As an example, here are two popular power meters. The first is the Favero Assioma DUO, a pedal-based power meter. The Assioma measures power in the pedal body and places its electronics in pods that are mounted on the pedal spindles.
The second is a Stages Cycling Shimano Ultegra R8000 Crankset. The Stages is a complete crankset and measures power using sensors and electronics placed along the inside of each crank arm.
Favero Assioma DUO
Stages R8000 Dual-Sided Crankset
2. How Do Power Meters Work?
Most power meters measure torque using what is called a strain gauge. A strain gauge is a tiny electronic device whose electrical resistance varies depending on how much resistance (strain) is put on them. In the case of a crank arm-based power meter for example, the strain gauge measures how much your crank arm is flexing when you push down on the pedals.
Graphical depiction of a strain gauge
Using electronics located within the power meter, the strain gauge converts this flex into an electrical resistance. Based on the amount of electrical resistance, the power meter can calculate how much torque the rider is generating.
The number of strain gauges, their alignment and the materials used all determine how accurate a power meter is. The precise measurement of torque is the biggest challenge power meter manufacturers face. The microscopic bending that the strain gauges must precisely measure is the key to accurate results. It requires an extremely high level of engineering and precision to fit the strain gauges within a power meter.
Data from the power meter is transmitted in real-time to a handlebar mounted computer or watch (aka head unit) via a wireless protocol such as ANT+ or Bluetooth SMART. The head unit displays power data such as current, maximum and average power. It also serves as an all-around cycling computer, displaying things like heart rate, speed, distance, time and much more. Note that power meters that feature Bluetooth SMART (the vast majority of power meters), can also interact directly with smartphones and tablets.
As an example, here are two popular head units:
Garmin Edge 520 Plus
3. Benefits of Buying a Power Meter
With cycling, many things affect how fast you go. Winds, gradients, weight, road surface and more all determine your speed, so it’s very difficult to gauge precisely how hard you’re working. With a power meter, you can directly measure your work rate and fitness. It takes the guesswork out of riding and allows you to quantify your efforts. Power meters provide an objective measurement of real output. This affords the rider numerous advantages.
Power meters have become essential tools for cyclists of all levels, their coaches as well as sports scientists – who use power meters as a fundamental way to measure and improve cycling performance. Power meters can unlock more endurance and speed than any other training tool.
Here are just a few of the ways you can use a power meter to improve your performance:
1. Eliminates Guesswork
Perhaps the biggest advantage to a power meter is that it removes the guesswork that goes into training and racing. With a power meter, you can quantify exactly how hard you are working (as your effort is measured in watts). Many people use a heart rate monitor in their training. However, heart rate monitors only tell you how hard the effort is to your body. They don’t tell you the actual amount of work you are performing. Watts are a much more accurate way to measure your effort.
2. Allows for Structured Training
When you just start out, you can improve your performance by following the ‘just ride lots’ technique. But soon, you will start to see your improvement slow. A structured training program where you focus on different intensities at varying durations is the ticket to continued improvements in power and performance.
3. Can Track Fitness More Accurately
Power meters provide highly accurate details about how your fitness is changing throughout the season. You can closely track your average power numbers at given distances, your maximum power numbers, your functional threshold power and more. Using software like TrainingPeaks and their Performance Management Chart, you can track a variety of important metrics. The information gained from this type of software and analysis is invaluable.
4. Race Pacing
We all know that in most long, steady-state races such as a triathlons and time trials, your best strategy is to pace yourself. You don’t want to start too hard and end up limping to the finish. Nor do you want to start too easy and finish with gas left in the tank. Well a power meter allows you to pace yourself almost perfectly. Once an athlete’s optimal power has been determined with a power meter, they can gauge exactly how hard to push during a race.
With a power meter, there’s no lying. You get immediate, accurate performance assessment. This can serve as a great motivational tool. There is nothing more satisfying then ending an interval or a ride and seeing an increase in your average or maximum power numbers. A power meter can really help you hit that 100% effort target and can serve as a great training tool because of this alone.
6. Communication with Your Coach
If you have a coach or are thinking about getting one, a power meter greatly improves the value that they can provide. A power meter will provide a wealth of data for your coach. In addition to power, things like speed and cadence are also informative. With this data, the coach can create a plan that is tailored to your needs and by continuing to view data from your rides, they can closely monitor your performance and make adjustments where necessary.
4. Types of Power Meters
Power meters have been around for quite some time, however in just the last few years, the power meter market has blown wide open. In addition to better power meters, we are seeing new manufacturers enter the market with more types of power meters than what previously existed.
The “type” of power meter refers to where on the bike the power meter measures power. For example, some power meters are built into your crank and measure force at the crank spider – whereas other power meters are built into the pedals. Currently, there are 6 locations on the bike to measure power.
1. Crank (Spider)
3. Crank arm
5. Bottom bracket
1. Crank (Spider)
Crank-based power meters are located on the cranks of the bike and measure torque using a strain gauge positioned inside the crank spider. These units require specific cranks or cranksets, but can be interchanged between bikes, depending on compatibility. Crank-based power meters are some of the most common power meters and are the most heavily adopted system by professional athletes due to their accuracy, consistency and durability. In addition, certain units such as the power2max and FSA can provide left/right power balance data.
Pedal-based systems incorporate strain gauges inside the pedal itself. Favero Electronics, PowerTap, Garmin and SRM/LOOK all make pedal-based power meters. Pedal-based systems are perhaps the most popular power meter. They are easy to install, simple to use, can measure independent left and right leg power and are compatible with almost any bike. These power meters all come with proprietary, 3-bolt road cleats that must be used with the power meter. Note that the Favero, Garmin and SRM/LOOK pedals can also be used with original LOOK Keo cleats.
Favero Assioma DUO
Garmin Vector 3
SRM LOOK EXAKT
3. Crank Arm
A crank arm-based power meter measures the forces in the crank arm. There are different variants of crank arm-based power meters. The Verve InfoCrank is a complete crankset (crank arms, spider and chainrings) and has a power sensor located in both the left and right crank arm.
Power meters from 4iiii Innovations, Stages Cycling and Pioneer also measure power along the crank arm. These three companies offer a complete crankset that measures power on both the left and right crank arms (like the Verve InfoCrank), however they also offer a left side only power-equipped crank arm. With a left only crank arm, you simply remove your current left crank arm and replace it with a power equipped one. These left side crank arms are very popular as they are both affordable and easy to install. Because they only measure your left leg power, they work by doubling your left leg power in order to calculate a total power figure. This method of calculation assumes that both legs produce the same force.
The PowerPod and AeroPod are handlebar mounted power meters manufactured by Velocomp. Unlike direct force power meters (DFPM) (all the other types of power meters discussed in this article) that measure your power using strain gauges, the PowerPod and AeroPod attach to your handlebars and measure your power through wind measurement – that is the forces that oppose the rider. This is called opposing force technology and therefore these power meters are referred to as opposing force power meters (OFPM).
Specifically, they use an accelerometer, a wind pressure sensor, an elevation sensor and a speed sensor – all to measure power. (The AeroPod is also able to measure your CdA when used in conjunction with a DFPM.) There are some advantages and considerations to this type of power meter. If you’re interested in learning more, have a look at our Direct vs. Opposing Force Power Meters article where we discuss this topic in detail.
5. Bottom Bracket
Bottom bracket power meters are similar to crank-based power meters in that your current crankset is often replaced for a new, power-equipped one (but not always, as the CINCH allows you to just purchase the spindle). However the location of power measurement differs. Bottom bracket-based power meters measure torque in the axle. ROTOR manufactures its 2INpower and INpower DM power meters. Likewise, Easton and Race Face offer their CINCH power meter.
ROTOR 2INpower DM
Easton & Race Face CINCH
With a hub-based power meter, the strain gauges are located in the rear hub. PowerTap remains the only manufacturer of a hub-based power meter. You can purchase a stand-alone G3 hub for as little as $399 or buy a complete wheel where the hub is already laced into a new wheelset (this option is of course a bit more expensive). PowerTap’s G3 hub has been a go-to power meter for years and remains a very popular option among cyclists of all levels.
PowerTap G3 Hub
PowerTap G3 Rear Disc Hub
5. Our Most Popular Power Meters
We thought it would be helpful if we listed some of our most popular power meters. This isn’t to say all of these power meters will be perfect for everyone…and we have lots of great PMs that aren’t listed below, but if you’re new to power, this is a good place to start.
Cost: $490-640 (spiders). $490-1,180 (cranksets)
Bike: Road, MTB, Track
- Dual-leg power measurement starting at only $490!
- Proven accurate and consistent is all weather conditions
- Models to fit virtually every crankset and frame
- Features such as L/R Balance, BLE, Auto-Zero and more
The power2max NGeco, the company’s latest version, measures power at the crank spider. It is therefore able to measure power from both legs, a feature typically only found on more costly power meters. In addition, it comes loaded with things like L/R Power Balance, ANT+ and Bluetooth, Auto-Zero and more. You can purchase a stand-alone spider, which you install onto your current crankset, or you can purchase a complete power2max crankset. The company makes versions for virtually every crankset or frame.
- The most affordable power meter pedals
- Highly reliable and consistent
- Independent left/right power
The Favero Assioma DUO offers all of the benefits of a power meter pedal (dual-sided power, easy to use, compatible with all bikes, etc.), but at a lower price point than other pedals – making it one of our best-selling power meters. It uses IAV technology making it super accurate (+/- 1.0% accuracy). It also has a fantastic track record of reliability and consistency. It’s also only one of two pedals that features a rechargeable battery.
Favero Assioma DUO
4iiii Left Crank Arm
Bike: Road and MTB
- One of the most affordable direct force power meters
- Lightest power meter (9 grams of added weight per side)
- Easy to install
The 4iiii PRECISION and Podium are the lightest and most affordable direct force power meters available. They are accurate, reliable and are simple to install. There are versions for both Shimano road and MTB cranksets.
- Pioneer’s 12-point force measurement for high accuracy and advanced metrics
- Independent left/right power
- HDPower Metrics when connected to Pioneer Cycle Computers
The Pioneer Dual-Sided Crankset measures pedaling forces every 30 degrees, for 12 points of measurement per pedal revolution. This level of measurement is unique to Pioneer power meters. When paired with a Pioneer Cycle Computer, you also get access to Pioneer’s HDPower Metrics. This includes Force Vector analysis, Torque Vector and Pedaling Efficiency power metrics. In addition, with a sensor on both crank arms, Pioneer cranksets can measure independent left and right leg power.
Pioneer Dual-Sided Crankset
Stages Left Crank Arm
Bike: Road and MTB
- Compatible across a wide range of cranksets
- Upgradedable to dual-sided power
- Easy to install
Stages power meters (specifically their left-crank arms) have been very popular for a number of years now. They feature 200 hours of battery life, are lightweight – adding only 20 grams to the weight of the crank arm and are compatible with both ANT+ and Bluetooth SMART devices. In addition, Stages makes a power meter for almost any crankset, including Shimano, SRAM, FSA, Campagnolo and Cannondale.
- Affordable with models starting at $199
- Compatible with any bike
- Light weight
- Easy to move between bikes
Unlike other power meters on our list which measure torque with strain gauges (direct force power meter), the PowerPod attaches to your handlebars and measures your power through wind measurement (opposing force power meter). While this type of power meter isn’t for everyone, it does offer some nice advantages over a more traditional power meter. The PowerPod starts at $199 (PowerPod Lite) and as you add options and features (PowerStroke, Bluetooth, etc.), the price increases.
Garmin Vector 3
- Easy installation
- Slim pedal design resembles a traditional pedal in look, size and shape
- Independent left/right power
The Garmin Vector 3 features left/right power, Bluetooth SMART as well as Garmin’s Cycling Dynamics when used with a Garmin head unit. While the previous version of the Vector was met with mixed reviews, the Vector 3 has received high marks for its modern design and slim form factor.
6. How to Choose the Right Power Meter
It’s important to understand that selecting and buying a power meter depends on a number of personal factors (your bike, budget, etc.). There is no such thing as ‘a best power meter’. The right power meter for you might not be good for the next person. If someone tries to tell you differently…they’ve either been brainwashed or they don’t have your best interests in mind. We never recommend a power meter to a customer until we understand their own unique set of circumstances.
When you’re looking to buy a power meter, there are really three main areas you should focus on: (1) Compatibility, (2) Features and (3) Price.
Compatibility simply refers to whether the power meter will fit with your current frame or components. For example, if you’re looking at a crank-based power meter, is it compatible with your frame and bottom bracket? Maybe you’re looking at a crank arm-based power meter. Is it compatible with your current crankset?
If the power meter you are interested in isn’t compatible with your bike or components, it’s time to look at another power meter. (Unless you’re willing to make a change to your components in order to accommodate the power meter – which isn’t unheard of.) The last thing you want to do is buy a power meter only to later find out it’s not compatible with your bike. So be sure to confirm compatibility before purchasing. All of our product listings contain a compatibility section – so you can look there for notes on compatibility, or give us a call and we can help.
In general, there are more options for the road then there are for the other cycling disciplines (mountain, track, cyclocross, etc.). Power meters started on the road and the market there is just bigger. However, as more power meters continue to enter the market, the other disciplines are quickly catching up so I’m certain you can find a power meter that will work for you.
There are several features you will probably want to consider when buying a new power meter. In general, we have listed them below in order – starting with the most important. But the order below is just how we look at power meters. Again, we all have our own unique set of considerations. Maybe you have to have a power meter you can move between bikes, in which case Transferability will be higher on your list. Alright, let’s check them out.
Accuracy refers to whether the power meter is indeed measuring what it claims to be measuring. For example, if it’s transmitting 225 watts to your head unit, are you actually producing 225 watts, or are you producing 215 watts instead? This has to be listed first as it’s usually one of the more immediate things people think about when buying a power meter. However, the truth is, while accuracy is of course key when using any power meter, this is not something most cyclists need to worry much about. All of the direct force power meters we carry and tried and true, and are very close to one another in terms of accuracy (+/- 1.5% or better) – assuming it is installed and calibrated correctly.
To be true, there are some super precise power meters that have been certified accurate all the way up to +/- 0.5%. So if that’s what you’re looking for, more power to you (pun intended). But again, for most cyclists, other features (and of course price), usually prove more important.
Nothing is more frustrating than a piece of faulty equipment. You want your power meter to work and be reliable, every day. Reliability is key when looking at power meters so be sure to do some research in this regard. Fortunately, most of today’s units rank high in terms of reliability. Again, contact us here with questions.
Transferability refers to how easy the power meter is to transfer from one bike to the next. If you have multiple bikes but only one power meter, it’s nice to be able to move the power meter from bike to bike. Some power meters are easy to transfer; others not so much.
In general, the easiest power meters to transfer are pedal-based power meters and opposing force power meters, such as the PowerPod. Hub-based power meters are also easy to transfer because all you have to do is move the wheel from bike to bike. Next easiest are usually crank arm-based power meters. Then there are crank (chainring or spider) and bottom bracket-based power meters – which can be moved among bikes – but typically aren’t due to the time it would take to do so, as well as potential frame compatibility issues between your bikes.
Installation usually goes hand-in-hand with transferability. Power meters that are easy to transfer are usually easy to install. The easiest power meters to install are pedal-based power meters, OFPMs, and hub-based power meters – assuming you buy a pre-built wheel set. Next easiest are crank arm-based power meters. Crank-based power meters on the other hand require more work. However, assuming you’ve purchased a power meter that is compatible with your bike and bottom bracket, even these are relatively straightforward to install, come with detailed instructions and mostly require common tools.
In addition, assuming you’re not moving the power meter from bike to bike frequently, keep in mind that installation is a one-time thing. So even if the installation process is a bit more involved, don’t let this deter you too much if the power meter checks all of your other boxes.
Left/Right Power Measurement
Some power meters offer independent left/right power measurement. With this feature, you can measure how much power each leg is generating independently. While left/right power measurement is a very cool feature, there is some debate as to how meaningful this information is and whether you can, or even should, try to even out any imbalances you might find.
There are two types of left/right power – actual and estimated. Power meters such as Verve Cycling’s InfoCrank or pedal-based power meters, measure both legs independently. They combine the data to give you total power. Verve does this by locating a power sensor on both crank arms. Whereas the pedals house a power sensor in each pedal.
On the other hand, power meters such as the FSA PowerBox only estimate how much of your total power is coming from each leg. This is because there is only one power meter on the bike (in this case in the spider), so the power meter needs to make some assumptions. The PowerBox takes power from your left and right down strokes only and ignores the upstroke. Since the majority of your power comes from the down stroke, it can estimate the power distribution fairly closely, just not exactly.
Your power meter will communicate with your bike computer, smartphone or tablet through one of two wireless protocols: ANT+ or Bluetooth SMART. Note that nowadays, most power meters are compatible with both.
ANT+ is a 2.4 GHz wireless network which is used to send standard information wirelessly from one device to another. It allows your power meter to communicate with your head unit. All power meters and head units we sell are compatible with ANT+ technology.
Bluetooth SMART technology is also a wireless protocol, however it allows you to connect your power meter with smart phones and tablets. It also allows for pairing with popular training apps such as Zwift.
There are three aspects you might want to consider when looking at the battery for your power meter: battery type, battery life and the ease of which it can be changed.
More and more power meters are coming with rechargeable lithium-ion batteries. Specifically, approximately 40% of the power meters we sell now feature a rechargeable battery. Rechargeable batteries offer a bit of a trade-off. You never have to worry about replacing batteries in your power meter, however battery life is typically less than that of a replaceable battery.
The next most popular battery is the CR2032 coin-cell battery, making up about 35% of the power meters we sell. These batteries are cheap and you can find them virtually anywhere. The remaining 20% represents AAA (PowerTap P2), LR44/SR44 (Garmin Vector 3 and Verve InfoCrank) and proprietary (SRM) batteries. We always recommend keeping a few batteries on hand as to eliminate the risk of being without a battery when you need one.
Battery life largely depends on the type of battery your power meter has. As mentioned previously, rechargeable batteries have a bit of shorter life on average. At last count, our rechargeable units averaged about 140 hours. This compares to 230 hours on average for power meters that feature CR2032 batteries. The range is wide for the ‘other group’ (remaining 20%) with the PowerTap P2 getting 80 hours off its AAA batteries while many SRM units get close to 2,000 hours off of the company’s proprietary battery.
Difficulty to Change
Assuming you have a power meter with a user replaceable battery, you will have to change it out from time to time (based on battery life and how much you’re riding). However, the act of changing batteries on the majority of power meters is pretty straightforward, so there is not much to worry about here. The only real exception is in case of SRM units that feature proprietary batteries. Those power meters must be sent back to the factory for a new battery. SRM is making most of their new units with rechargeable batteries however.
With this option, a magnet is attached to the bike frame and cadence is detected using a reed switch. For example, on a crank-based power meter, the reed switch will be located in the power meter itself. As the crank turns, the reed switch will pass by the magnet and the magnetic field generated by the magnet will set-off the reed switch. This is considered the most accurate way to measure cadence. However the downside is a magnet has to be attached to your bike frame, usually using adhesive tape or glue, and some prefer not to have to bother with this application. We also note that only a handful of power meters still use magnet-based cadence detection.
The vast majority of power meters use an accelerometer to measure cadence. An accelerometer is a device housed inside the power meter and measures proper acceleration. With an accelerometer, everything is internal to the power meter and there is no magnet to mount. Some argue that a tiny bit of precision is sacrificed with the use of an accelerometer vs. a magnet…but the difference is negligible.
Crank Position System (CPS) Technology
Verve Cycling measures cadence internal to the cranks, using the strain gauges to read the tangential load. Their algorithm uses Crank Position System (CPS) technology. CPS accurately detects cadence pulses regardless of power or pedaling style. With CPS, you have the accuracy of a magnet without having to have one mounted to your bike.
All power meters add weight, some more than others. Power meters such as a left-side only crank arm-based power meter might only add 10-20 grams to your bike, while others might add closer to 200-250 grams or more (but this all depends on the component you are replacing). When factoring in the weight, remember to focus on added weight by taking into account the component you’re replacing. For example, if the crank-based power meter you’re considering weighs 700 grams, and your current crank weighs 500 grams, the net addition is 200 grams.
While it’s important to pay attention to how much weight is added and where, it’s not worth fussing over. The benefits of training with power will more than offset any weight gain. If you’re a weight weenie (and we don’t say this is a bad way), weight might move up on your list. Otherwise, we think it’s safe to keep it here.
Power meters start at around $199 and and reach $2,000 or more. Some of the more expensive power meters offer features like independent left/right power measurement as well as high levels of accuracy and consistency. However, this isn’t to say that a lower priced power meter can’t do the job. In fact, nothing could be further from the truth. The vast majority of power meters are very capable assuming you have them set up properly and calibrated – so don’t assume that more expensive is necessarily better. If you find a power meter that meets your criteria and is in your price range – than it’s likely a winner for you.
7. Cost/Benefit of Buying a Power Meter
So you’re convinced that a power meter is the single most effective training tool a cyclist can use for improving performance, but you think they are too expensive? We would argue differently. Cyclists often spend hundreds and sometimes thousands of dollars upgrading the components on their bike…and we can’t think of a single upgrade that can offer the potential gains that a power meter can. Power meters are simply an invaluable piece of technology when it comes to cycling performance.
In addition, due to the rise in popularity and the increased use of power meters across all cycling disciplines, more manufacturers have entered the market. More power meters results in a more competitive environment, which means lower prices. With prices now starting at $199, there is no reason not to be riding with power!
8. The Power Meter City Difference
We would be remiss if we didn’t briefly mention why we think we are best suited to help you when you’re ready to buy a power meter. (We’re biased…but we think we’re pretty great.)
At Power Meter City, we focus on ONE area and one area only: power meters. Unlike others, we don’t deal with other bike parts, clothing, miscellaneous accessories or anything else that can distract us from what we love – yes, power meters!
Our singular focus means we are your power meter specialists – and can offer you the best possible value, selection, advice and support. Here are 10 reasons to shop with us:
1. Power meter specialists that can provide expert advice and customer service
2. The largest selection of power meters and accessories with power meters starting at $199
3. Free U.S. and international shipping on most orders
4. Fast order processing and same day shipping
5. Power meter knowledge center with additional information and resources
6. Customer support 7 days a week
7. 100% satisfaction guarantee on all orders
8. Financing available through PayPal Credit
9. 20% off TrainingPeaks Premium with the purchase of a power meter
10. 5 star (Excellent) customer service rating on Trustpilot
Well that’s it. Thanks for reading our Beginner’s Guide to Buying a Power Meter. Please contact us with any questions!