SEVEN THINGS TO CONSIDER
All you need to know before buying a power meter
NARROW YOUR OPTIONS
A power meter is, first and foremost, a tool designed to improve your training and racing. If you don’t plan on doing targeted training sessions, testing your fitness or using it to pace yourself during races or big rides, a power meter perhaps isn’t worth the outlay.
If you do want a power meter, the first thing to consider is what kind of riding you do and what compromises you’re willing to make with bike components. This’ll narrow your options considerably. If you only need power data on a road bike, then your options are wide. If you want to use the same power meter across multiple bikes and for multiple disciplines, then your options become more limited.
A power meter based around a roadpedal wouldn’t be ideal for use on your
Ultimately, there is a compromise of some kind with every power meter you can buy
gravel bike, for example. And, ultimately, there is a compromise of some kind with every power meter you can buy – there’s no ‘one size fits all’ solution for every bike and type of riding.
Also keep in mind that, unless you’re a WorldTour pro, your numbers aren’t likely to blow anyone away. Power meters are also arguably a young rider’s tool. After all, past a certain point, a power meter just tells you how much fitness you’re losing with each passing year.
CRANK V SS PI DE RV SPED AL
Three of the most common power meter options are crank-based, spider-based and pedal-based. Pedal threads are the same on practically every crankset available, meaning pedal-based power meters can be attached to almost any bike, with no modifications required.
A crank-based or spider-based power meter, on the other hand, might require you to swap the bottom bracket on your bike to make it compatible with the new axle. If you have multiple bikes that you want to measure power on, the cost of converting them all to the same bottom bracket standard could quickly add up.
Cranks also take a few minutes longer to swap between bikes than pedals. With pedal-based power meters, though, you’re limited to using the pedal body types that the power meter is compatible with. For some models that may just be one road pedal standard, but even for those which have interchangeable pedal bodies, not every cleat and pedal system is catered for.
Once you have a power meter, you’ll need something to capture the data. And while many power meter brands offer dedicated apps for recording data on your smartphone, a dedicated ANT+ compatible bike computer is a better option. Especially one with a large data screen to present all the data.
BEWARE LEFT/ RIGHT SPLITS
As with anything, cheaper options often come with compromises compared to more expensive options. Single-sided power meters only measure the power output of a single leg (this figure is then doubled to estimate total power), and therefore only require half the electronics so they tend to be significantly cheaper.
The biggest disadvantage of singlesided power meters is that the accuracy of the total power data produced depends on your left/right power balance. Any imbalance introduces a further margin of error, reducing the precision with which your metrics are measured.
DUAL SIDED BENEFITS
Many power meters now offer a range of advanced metrics such as left/right power balance, pedal smoothness and torque effectiveness. Left/right power balance is a measure of how much power each leg is contributing to the total power being produced. This is usually displayed on head units as a percentage split.
True dual-sided power meters consist of two separate power meters that measure each leg independently and combine the data from each to give a precise total power. If you do have a large imbalance, this may be something you can target to improve with the use of a dual-sided power meter.
Your power meter has a practically endless list of metrics you can track and evaluate
FEEL THE FORCE
Pedal smoothness measures how smoothly force is applied throughout each full, 360-degree rotation of the crank. A perfectly smooth pedal stroke, where the power was applied evenly throughout the entire rotation would give a pedal smoothness reading of 100 per cent, with each leg being assigned a separate score. Most cyclists will see a pedal smoothness reading between 10 and 40 per cent.
Though there are claims that improving your pedal smoothness can improve your performance, a 100 per cent pedal smoothness score isn’t desirable. This is because the majority of the force should be generated on your downstroke, to take advantage of the biggest muscle groups in your lower half, the glutes and quadriceps.
Another measurement is torque effectiveness. This measures how much of the force (torque) being generated is pushing the pedal or crank arm forward. Like pedal smoothness, this is measured as a percentage and each leg is measured separately. A torque effectiveness of 100 per cent for both legs would mean all your effort is going into pushing the pedals forward, though this is difficult to achieve in practice.
THE IMPORTANCE OF ANALYSIS
Once you’ve finished your rides, you’ll need to have access to dedicated software to review your data. You can use these programmes to calculate your training load and progress, track how many calories you’re burning, review your personal records and more. There’s a practically endless list of metrics you can track and evaluate.
Key tools include Garmin Connect, which is a free service that clearly presents a variety of metrics, and incorporates insights into your current fitness and training load via its Training Status feature. Strava offers a similar package, but these features are reserved for subscribers to its premium service.
Those working with a professional coach may be best served by TrainingPeaks, which offers a vast array of in-depth analysis tools and training plans. For those who like open-source (free!) software, GoldenCheetah offers an offline software package that incorporates a huge range of data analysis tools with amazing functionality.
DEMAND ACCURACY
Most manufacturers will claim their power meters are accurate to within +/- one to two per cent. It’s typically the case that the more expensive a power meter, the tighter the claimed margin of error will be. Fortunately, we have multiple power meters from a wide variety of brands to cross reference against one another. This enables us to put those claimed accuracy levels to the test. Turn overleaf for our pick of the best power meters on the market…
If you just want the basics done well the Quarq is a reliable and accurate option