So, You Want to Train with Power? Here’s What You Need to Know
You’ve probably heard people talk about power meters like they’re some secret weapon for cycling performance—and they kind of are. A power meter is one of the most effective upgrades you can make if you want to take the guesswork out of training and get serious about measurable progress.
But choosing one? That’s where things get tricky. Crank, pedal, spider, hub… each has its strengths and trade-offs. If it feels overwhelming, don’t worry—you’re not alone. In this guide, we’ll walk you through the different types of power meters, what makes them tick, and who each one is best suited for. Whether you’re racing crits, chasing KOMs, or just want to make your training time count, there’s something here for you.
But before we dive in, let’s quickly cover how these clever devices actually work.
How Does a Power Meter Work?
At the core of nearly every power meter is a component called a strain gauge. This small but powerful sensor measures tiny deformations in metal when force is applied—like when you press down on your pedals. The strain gauge detects how much the material flexes under pressure, and from this, it calculates the torque you’re generating. Combined with your cadence (how fast you’re pedalling), the device then calculates your power output in watts.
Cool fact: Strain gauges were originally invented for structural engineering and aerospace applications—designed to measure stress on aircraft and bridges. So next time you’re grinding out intervals, remember: you’re using tech originally built to keep planes in the sky.
Examples: Stages, 4iiii, Shimano, Giant
Crank-based power meters are a popular and proven choice. They’re typically installed on one or both crank arms and use strain gauges to measure the torque you apply with each pedal stroke. That torque, combined with cadence, gives you a real-time power reading. Since they’re located close to where the force is generated, they provide responsive and reliable data.
You’ve got two main options here: single-sided or dual-sided. Single-sided meters (usually left-only) estimate your total power by doubling one leg’s output. It’s more affordable, but not as precise. Dual-sided meters measure each leg independently and are great for spotting imbalances or tracking rehab progress.
They’re also pretty sleek and low-profile—hardly noticeable on the bike. Just keep in mind that not every crank-based meter works with every crankset, so you’ll want to check compatibility before you buy. Still, for most riders with one main bike, they’re a rock-solid choice.
Pros:
- High accuracy, especially in dual-sided models
- Lightweight and blends in with your setup
Cons:
- Crankset compatibility can be a limiting factor
- Not ideal if you frequently switch between bikes
Best for: Riders with a dedicated race or training bike who want reliable, high-quality data.
Pedal-based power meters are fast becoming a go-to for cyclists who want flexibility and convenience. These replace your standard pedals and measure force right at the spindle—the point where your effort meets the bike.
They’re super easy to install with a standard pedal wrench, making them ideal for anyone who switches between bikes or travels regularly. Many systems also offer dual-sided readings, giving you detailed insights into left/right balance and pedalling dynamics like platform centre offset or power phase.
Because they sit externally, they’re slightly more vulnerable to knocks and weather, but most modern models are built tough. Some riders also notice a tiny weight increase compared to regular pedals, but for most, it’s a non-issue.
Pros:
- Quick and easy to move between bikes
- Dual-sided options give deep performance data
- Works with almost any crankset
Cons:
- Slightly more exposed to damage and the elements
- Can be a bit pricier than other types
- A bit heavier than standard pedals
Best for: Riders with multiple bikes or anyone who values convenience and data-rich feedback.
Spider-based power meters sit at the centre of the crankset, between the chainrings and the crank arms. It’s a prime location for accurate torque measurement because it captures the total output from both legs at once.
They use multiple strain gauges to detect how the spider flexes under load and combine that with cadence to deliver your power output. Since this happens centrally in the drivetrain, the data is consistent and unaffected by how your legs are working individually.
They’re stable, reliable, and well-suited to racers or those who want top-tier data with minimal fuss. Some models include auto-zeroing and temperature compensation, so you spend less time calibrating and more time riding. The trade-off? They’re integrated into the crankset, so switching bikes is a hassle, and the upfront cost is usually higher.
Pros:
- Accurate, consistent power readings
- Great for interval training and race pacing
- Handles varied conditions without a fuss
Cons:
- Harder to move between bikes
- Can be expensive, especially with compatibility upgrades
Best for: Racers or anyone training seriously on one main bike.
4. Hub-Based Power Meters
Examples: PowerTap (now discontinued)
Hub-based power meters were once the go-to choice, built right into the rear hub of your wheel. They measure the torque delivered through the drivetrain—after all the losses from the chain, cassette, and everything else.
That means they reflect the power hitting the rear wheel, not what’s being produced at the cranks. If your chain is dirty or your drivetrain’s not running smoothly, your readings will be lower than what you’re actually putting out.
They’re no longer being manufactured, and support is limited, But they were once a great piece of kit but have since been surpassed by modern solutions thanks to advancements in sport science and technological improvements.
Pros:
- Durable and consistent under controlled conditions
- Simple, no-fuss power tracking
Cons:
- No longer in production
- Power readings affected by drivetrain efficiency
- Not transferable between bikes without swapping wheels
Which One Should You Choose?
Picking a power meter comes down to what kind of rider you are. If you ride multiple bikes and want something that’s easy to move between them, pedal-based power meters are hard to beat. They’re flexible, straightforward, and packed with useful data.
If you train seriously on one bike and want the most consistent, precise measurements, spider-based or dual-sided crank meters are ideal. They’re dependable and perfect for structured training and racing.
And if you’re just starting out and don’t want to spend a fortune, a left-side crank meter still gives you a solid foundation for training with power.
Whatever your choice, the most important part is that you’re making your training measurable, trackable, and tailored to your goals.
