While crank- or spider-based power meters are less easily swapped than power pedals, they are more reliable and less prone to damage. For most riders, a single-sided, left crank option provides sufficient data with enough accuracy and can be bought for considerably less, but if every data metric matters, then a left-right model is the answer.
The Stages Dura-Ace G3 L-R Power Meter is Team Ineos’s chosen power meter and, as such, has recorded the last three Tour de France wins.
Two crank-based meters add £700 to the standard Dura-Ace chainset’s cost, but it’s on a par with most of the equivalent competition and cheaper than Shimano’s own meter.
However, SRAM’s Red AXS meter costs less, but is less interchangeable, while the Ultegra LR Stages is cheaper still.
Stages Dura-Ace G3 L-R Power Meter details
Stages’ polycarbonate measuring pods fit on the inside of the left crank and alongside the driveside crank within the spider. Each pod is powered by a CR2032 battery, which should last for 150 to 200 hours of use and includes a start-up LED indication of current battery level.
Connection is via ANT+ or Bluetooth Smart and firmware updates can be done wirelessly. Once paired with your handlebar head unit, Stages recommends performing a zero reset, or calibration, before each ride to compensate for ambient temperature changes and variations in the attachment torque of the chainset to the bike.
Thankfully, it’s a simple operation, which takes around 30 seconds. The left side unit is the primary meter, receiving and processing signals from the right. If one side’s battery dies, the other can continue as a single-sided power meter.
Start-up is immediate as soon as the bike is moved, and when my Garmin was left outside the garage it acknowledged the Stages’ signal from 5 metres away.
Cadence is measured by an accelerometer and a gyroscope over a 20 to 220rpm range and power is measured up to 2,500 watts, with a claimed accuracy of ±1.5 per cent. Stages says its Active Temperature Compensation system is designed to ensure data consistency, regardless of how the temperature fluctuates.
The ANT+ values transmitted are total power, left/right balance, cadence, pedal smoothness and torque effectiveness, while power, power balance and cadence can be transmitted via Bluetooth Smart.
If using Stages’ Dash head unit, several more maintenance-related details are recorded. There’s also a Stages app with some useful functionality.
During my test, I compared this meter’s data to my familiar Quarq, and used three different head units to measure connectivity.
Stages Dura-Ace G3 L-R Power Meter overall
After two months of riding, I’m satisfied that the Stages LR unit produces reliably stable and accurate data, tracking my Quarq system during static and mostly outdoor tests, and I didn’t suffer from any transmission dropouts.
Data display is prompt with close to real-time figures flicking up and down on the head unit’s screen.