Ask a Gear Guru: What Are the Best Power Meters for Triathletes?
This article originally appeared on Triathlete
If you've been in the sport for even a little bit, you'll recognize that the biggest enemy of any triathlete is time (and chafing…also chafing). There's never enough time to get in those workouts, proper recovery, good nutrition, stretching, strength training, injury prevention--not to mention those other pesky little hindrances like time with your family, friends, and work. Because of this, triathletes are always looking for the best way to optimize the time they spend training. For cycling, using a power meter is one of the best ways to get better by eliminating most of the guesswork behind effort. And as we learned in this piece about Ironman World Championship St. George third-place finisher, Braden Currie, it’s all about watts if you want to stand on the podium.
What Is Power?
Put very simply, power meters measure the amount of force the rider is applying (torque) times the angular velocity (cadence). This means that the power number you see on your computer is a direct result of literally how hard you're pushing down on the pedals. With the exception of some microscopically small losses of force through the drivetrain (if it's wheel-based or on a trainer) or other modes of transmission, what you put down is precisely what you get out. Unlike speed, if it's windy out, it doesn't matter; if you're riding up or downhill, it doesn't matter; rough roads don't even matter. And unlike heart rate, there's no cardiac drift or major effects due to temperature, fatigue, etc. So all of the guesswork that would come with heart-rate or speed training on imperfect places like roads are eliminated with power meters. Most power meters use strain gauges placed in various parts of the pedal-to-tire force chain, but a few use air pressure and other methods. Check out our links below for (way) more on training with power for triathletes.
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So What’s the Best Power Meter For Triathletes?
It depends. Obviously budget is a big part of it--power meters are not at all necessary for someone looking to do their first (or probably even their second) tri. While there has been news about crazy cheap power meter parts being offered to manufacturers, time will tell if they're any good or if they'll make it to market. But budget aside, there are features and functions that make an ok power meter the best power meter for one triathlete and a complete waste of money for another. First, we'll look at what makes a good power meter the best power meter for triathletes, and then we'll go through some picks.
What's The Point?
First, you need to ask yourself why you're getting a power meter. The most important answer should be "to train more precisely." After that, you can think about playing on Zwift or trying to hit "high power scores" to compare with buddies. Another good reason is to race better by pacing more effectively and dialing in your nutrition (power can help you determine calories spent!). Not only will your workouts be more precise and quantifiable, but you can determine exact zones for pacing with power as you race in order to avoid blowing up or still having too much left in the tank--even on hilly courses or unexpectedly windy days. Average speed gets thrown out the window completely in both conditions, when it comes to pacing.
Of course, there are other factors to consider when it comes to gauging effort and caloric expenditure on the bike for racing, but a power meter can fill in a big piece of the puzzle. In other words, the best power meter for a triathlete has to address your needs: If you're going to race with it, be sure it's not wheel-based and trapped on a set of training wheels you'd never race on or glued to a trainer in your garage.
Where Will You Go?
Do you have multiple bikes? Do you ride on a road bike some days and your tri bike on others? Do you travel and rent bikes at your destination--be it for races, training camps, or work? Do you ride inside? Do you ride road one day and gravel the next? If you're only going to use it training indoors, maybe a smart trainer is the best option; if you need to take it outside, then look for something bike-based. If you switch bikes often, maybe look at something pedal or wheel-based. If you travel quite a bit, stick to pedals.
Accuracy Matters, Right?
This is a tricky one. Instincts say that accuracy should always be a priority when choosing the best power meter for triathletes, but actually repeatability matters more than anything else. Even the most accurate power meters in the world need to be calibrated often--due to changes in temperature and other conditions--so if you're not calibrating properly, accuracy is not super important. In fact, knowing how easy (or not easy) it is to calibrate your power meter is a big draw in which one to buy.
That said, accuracy matters most when you're comparing to external numbers from other devices, like in a lab when you're doing testing. Consistency matters most for one person riding one power meter all the time: If it's always off by 10 watts, then it doesn't matter too much if all of your FTP testing, workouts, races, etc. all occur at 10 watts lower than the most precise power meter you can buy. It's the repeatability (via constant and proper calibration) that matters most. If you use different devices often, then accuracy matters much more.
Power Your Power
This is something a lot of first-time power meter buyers don't think about, but they should: How does my power meter get its juice? Power meters have traditionally had to be hermetically sealed to prevent the elements from intruding upon the super sensitive electronics inside, and back in the day, the only way to access the batteries buried deep inside was to send it into the manufacturer for servicing. Today, things are better, as most power meters have user-serviceable batteries, but some of those batteries run out pretty quickly if you're riding a lot, and it's not like they take the double-As you can find at the 7-11 down the block. So it's important to note when a power meter has a rechargeable battery (that still lasts long) or knowing how hard/not hard it is to change when the time inevitably comes.
Armed with a little more information on what makes the best power meters for triathletes, let's take a look at a few picks, based on features and reviews.
Best Power Meter For Triathletes Who Need Flexibility
Wahoo Speedplay Powrlink Zero Pedals
Starting at $650, wahoofitness.com
If you look at the features and stats on the new Speedplay Powrlink Zero pedals, they’d line up pretty squarely with what you find on other systems: +/-1% accuracy, available in single-sided ($650) or dual-sided ($1000), and a rechargeable 75-hour battery. But the true story behind these pedals is particularly important for triathletes--Speedplay has the most (15-degrees) and most-adjustable amount of float in the entire power-pedal market. For triathletes, this is huge because many triathletes have traditionally depended on the extra float in Speedplay pedals to help with knee and other upper-to-lower leg injuries and imbalances. Even better, these pedals weigh in at a scant 250g (276g for dual-sided)--though that doesn’t account for the large cleat you need. For more pros and cons in this system, check out our basic review or our deep dive.
Best Value Power Meter For Triathletes
4iiii Precision 3 Power Meter
$334, 4iiii.com
This upgrade to the previous kind of the budget power meters--the Precision--still features an easy, tool-free replaceable 2032 battery (which, yes, you should be able to find at the local grocery store). But it also has a staggeringly long 800-hour battery life, which is nearly untouchable industry wide. Of course, despite its price, the Precision 3 also has the features you’d expect in a modern power meter: +/-1% accuracy and ANT+ and Bluetooth transmission to pair with your cycling computer, computer, or smartwatch. And as a virtue of its design, the device itself only weighs an additional 9 grams on top of the crank weight (which you need anyway). Available in crank lengths from 165mm to 175mm, users can get the Precision 3 preinstalled on the full range of Shimano cranks from 105 to Dura-Ace and GRX to XTR (for mountain).
Best Dual-Sided Value Power Meter For Triathletes
Favero Assioma DUO
$730, favero.com
In terms of combination portability and functions, the Assioma is tough to beat. With a dual-sided power meter, riders can squeeze every drop of data out of each training session--looking at balance between left and right pedals, smoothness, efficiency, and more. Very cool features like automatic temperature calibration and a light weight at 152g per pedal, Favero packs a ton into a ANT+ and Bluetooth-compatible setup that could easily go for $1,000. The only downside to this pair is the fairly low 50-hour battery life--lower than both the Garmin (120 hours, replaceable) and the Wahoo Speedplays (75 hours, rechargeable) but they’re easily rechargeable.
Best Power Meter For Versatility
Garmin Rally Series
Starting at $650, garmin.com
The long (long) awaited update to Garmin’s Vector 3 (the dual-sided version) and 3S (the single-sided version) is the Rally series. The big news about the Rally series is that the pedal body can be swapped out for Shimano SPD-R (Shimano road), Look-compatible road, or SPD (Shimano mountain). The swap isn’t exactly the kind of thing you’d want to do every day, but it takes about 10 minutes and only a limited amount of technical knowledge. The conversion kits, however, run $200 (road) and $250 (mountain), so the flexibility comes at a slight cost. Adaptability aside, these are very accurate dual-sided pedals (+/-1%) that have 120 hours of battery life (user-replaceable 4x LR44/SR44 or 2x CR1/3N). They weigh in at a fairly standard 320g (SPD-R) to 444g (SPD) and measure a staggering amount of data. Check out our full review here for more.
Best Indoor Smart Trainer With Power Meter For Triathletes
Wahoo Kickr Core
$900, wahoofitness.com
This smart trainer is built like a rock--exactly what you want in a wheel-on system that measures power and gives feedback from virtual training environments. Both ANT+ and Bluetooth-compatible, this trainer hooks on to your bike's rear end to provide you with a super stable (but also easy-to-move) platform to measure watts, do workouts, and more. With an accuracy of +/-2%--pretty much around the industry standard for trainers--there's a lot you can do with the 1800W max ceiling and 16% simulated grade. Unlike some other brands, expect instant and rock-solid connectivity with devices and virtual platforms.
Best Alternative Power Meter
Velocomp PowerPod Lite
$250, velocomp-llc.com
Unlike the other power meters in this guide, the PowerPod uses a combination of wind sensors, barometric sensor, accelerometers, and a host of calculations to deliver a power reading that's said to be accurate to within -/+2%. By simply mounting to your handlebars and connecting to a Bluetooth or ANT+ speed sensor and computer, the PowerPod sets up super quickly. Bear in mind, you won't get any pedaling analysis or other high-end cycling dynamics, but in terms of price, low-profile, and simplicity, this could be a good solution if you're willing to think outside of the box.
Best Cycling Computer For Displaying Power
Hammerhead Karoo 2
$400, hammerhead.io
Though there are more data-driven cycling computers out there, none display your information or navigational maps in such a clean, engaging way. Using a huge 3.2-inch color touchscreen with resolution that comes close to an iPhone (nearly 300dpi), the view from this cycling computer is nothing short of beautiful. Better yet, the size of the latest Karoo is substantially smaller than the previous version and it can be mounted between aerobars without too much struggle. Why is this such a good choice when Garmin devices might crunch more data? It’s simple: No one uses graphical displays to convey data like power in such an intuitive way at a glance. You don’t want to be trying to decipher 20 fields of raw numbers when you’re cross-eyed halfway through an iron-distance bike.
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