Specialized Power Crank review

Power to the people

Our rating 
4.0 out of 5 star rating 4.0
GBP £420
Left-sided power crank road bike

Our review

Specialized’s left Power Crank is quick to fit and very simple to make effective use of
Pros: Simplicity, value, reliably accurate data display
Cons: Left side-only option only for UK Shimano users

Specialized teamed up with power specialists 4iiii to create its own dual-sided crankset, and this more affordable left side-only power crank.


Only available for Ultegra (in lengths of 170mm–175mm) my R8000, 175mm power crank weighs 210g, compared to the 175mm, 193g R6800 Ultegra crank I replaced.

The power unit consists of a raised module on the inboard side of the crank; use the hex wrench to remove two screws, then lift the cover to peel the protective film from the coin cell battery. Replace the cover and fit the crank in the usual way.

The Power Crank works with all ANT+ and Bluetooth devices, I switched on my Garmin, span the cranks a few times and the meter was detected. Or, manually input the numerical code printed on the power module into your device.

Specialized’s Power Cranks app can also be used for set up and diagnostics from a smartphone. A simple zero offset calibration is required on first use, and is advised every week, or when seasonal temperature changes occur.

From the off, the Power Crank performed as expected, and in line with other more expensive dual-sided meters I’ve tested

Specialized created a treadmill test rig, nicknamed the WinMill, to accurately test its power meters in realistic riding scenarios, such as seated or standing and at differing cadences or weights.

Its data was validated by Boulder’s Locomotion lab, and resulted in confirmed +/- 1.5 percent accuracy, a figure that’s also been quoted by several competitors, but Specialized believes its test protocol makes its product claim more realistic.

From the off, the Power Crank performed as expected, and in line with other more expensive dual-sided meters I’ve tested. There was no data transmission dropout, just smooth and consistent readouts of all metrics, such as current, average, normalised and maximum power, plus cadence.

Overall power figures are extrapolated from the single-side measurement accurately enough, but I was unable to view any similarly created balance data.

The main reason Specialized’s meter housing is larger than 4iiii’s own is its improved weather seals. I had no problems throughout a very wet spring, or after post-ride bike washes, which wasn’t a great surprise, because the unit is intended to shrug off daily pro-team jetwashing.

If you’re a Shimano user, Specialized’s Power Crank is one of the cheapest and most reliable ways of joining the power training party. Not quite fit-and-forget, but it certainly isn’t onerous in daily use.


Specialized Power Crank specifications

  • Side: Left
  • Upgrade kit: Shimano Ultegra upgrade kit (Shimano 105 available USA market – $425)
  • Connectivity: ANT+ and Bluetooth devices
  • Accuracy: +/- 1.5% tested on the WinMill
  • Apps: Easy set-up and diagnostics with the Specialized Power app
  • Sizes available: 170–175mm crankarm length
  • Price: £420 / $525 / AU$725