A cycling power meter is the single most transformative purchase you can make for your training. Heart rate tells you how your body is responding. Power tells you exactly what your body is producing. One is reactive, the other is absolute.
If you're serious about improving — whether that's raising your FTP, nailing your training zones, or pacing a race — a power meter removes the guesswork entirely.
Types of Power Meter
Pedal-Based
Examples: Favero Assioma, Garmin Rally, SRM X-Power
Strain gauges in the pedal spindle measure force applied through each pedal stroke.
Pros: Easy to swap between bikes. Available in single and dual-sided. No special tools needed. Cons: Adds weight to the pedals. Must use compatible cleats. Vulnerable to pedal strikes.
Best for: Riders with multiple bikes, or anyone who wants portability.
Crank-Based
Examples: Stages, 4iiii, SRAM Quarq, SRM
Strain gauges bonded to the crank arm or spider measure deflection under load.
Pros: Well-proven technology. Hidden from view. Wide compatibility. Cons: Bike-specific. Single-sided options only measure one leg. Spider-based units are expensive.
Best for: Riders with one primary bike who want a clean setup.
Hub-Based
Examples: PowerTap (now less common)
Strain gauges in the rear hub measure torque at the wheel.
Pros: Measures true total power. Reliable. Cons: Locked to one wheel. Heavy. Limited availability now.
Smart Trainers
Your indoor trainer likely measures power too. Accuracy varies but modern direct-drive trainers (Wahoo KICKR, Tacx NEO) are within 1-2% of dedicated power meters. Fine for indoor training. If you're deciding which to buy first, see our power meter vs smart trainer comparison.
Single-Sided vs Dual-Sided
Single-sided meters measure one leg and double it. If your left-right balance is roughly 50/50, the reading is accurate enough for training. Most riders fall within 48-52% balance.
Dual-sided meters measure both legs independently. More accurate total power, plus left-right balance data. Worth it if you can afford it, but single-sided is not a compromise that will hold you back.
My recommendation: Start with a single-sided Stages or Favero Assioma Uno. Upgrade to dual-sided later if you want the extra data.
How to Actually Use Power Data
Buying a power meter without understanding the data is like buying a heart rate monitor and ignoring the numbers. Here's what matters:
1. Establish Your FTP
Your Functional Threshold Power is the anchor for all your training zones. Test it properly — we cover this in detail in our FTP guide.
2. Train in Zones
Power zones remove ambiguity from every session. Zone 2 means Zone 2. Threshold means threshold. No more accidentally turning an easy ride into a moderate one.
3. Track Trends
Single sessions don't matter much. Trends over weeks and months tell the story. Is your 20-minute power improving? Is your power-to-weight ratio shifting? Are your VO2max intervals producing higher numbers?
4. Pace Events
Power transforms event pacing. Instead of going on feel and blowing up, you set a target wattage and ride to it. This alone can improve your sportive or race performance by 5-10%.
Common Mistakes
- Chasing numbers every ride. Not every ride is a test. Easy rides should be easy.
- Comparing to others. Your numbers are your numbers. Focus on your own progression.
- Ignoring conditions. Power is absolute, but your ability to produce it varies with fatigue, heat, altitude, and nutrition.
- Over-analysing. Average power and normalised power for the session, plus interval targets. That's 90% of what you need.
Key Takeaways
- A power meter is the most impactful training tool you can buy
- Pedal-based meters offer the best versatility across multiple bikes
- Single-sided is accurate enough for training — don't let budget stop you
- Establish your FTP first, then use our FTP Zone Calculator to set your zones
- Track trends over weeks and months, not individual sessions
- Use power to pace events — it prevents the blow-up that ruins most riders' races
- Zero-offset before every ride for consistent data
- A smart trainer provides good power data for indoor sessions
- For time trialling, a power meter transforms pacing from guesswork to precision
- Triathlon pacing relies entirely on accurate power data — it's the most valuable investment for Ironman racing