A complete Shimano GRX FC-RX810 48/31T gravel crankset with a 4iiii Precision 3+ power meter already on the left arm. Useful when you are fitting a new crankset anyway and want power from day one, with Apple Find My to help track the bike.

Highlights

• Complete GRX FC-RX810 double crankset, 48/31T
• Precision 3+ left-side power meter: ±1% accuracy from three strain gauges
• Apple Find My, ANT+ and Bluetooth
• 9 g pod, CR2032 coin cell, up to 800 hours
• IPX7 water resistance and a 3-year 4iiii warranty

The crankset

Shimano GRX FC-RX810 (the double, FC-RX810-2) is an 11-speed Hollowtech II crankset with 48/31T rings on a 110/80mm BCD four-arm spider, a 47mm chainline and a 151mm Q-factor. The arms and rings are aluminium, and Shimano quotes 710 g at 170mm without bottom bracket. The power meter measures from the left arm; left/right balance needs the dual-sided Precision 3+ PRO.

Set-up and calibration

Wake the pod by turning the crank three or four times, pair it with the 4iiii app to update firmware, then add it to your head unit over ANT+ or Bluetooth. Zero offset before you ride: bike upright and still, cranks at 12 and 6 o'clock with the left arm down. Apple Find My is set up from the Find My app on an iPhone, iPad or Mac; the pod starts reporting its location once it has been still for about four minutes.

Fitting at Tune

Fitting, pairing and calibration are separate workshop services and aren't included in the price. The Tune workshop can check your bottom bracket, fit the crankset with the correct Hollowtech II tools and torque, check clearance on both sides, and pair and zero the meter. If your frame needs a new bottom bracket, the right BB tool or press for your shell matters, and we'll quote it separately.

Options

Compatibility & fit

For Shimano 11-speed double drivetrains with an HG 11-speed chain. It needs a Hollowtech II bottom bracket, which isn't included: Shimano recommends SM-BBR60 for threaded 68mm or 70mm shells and SM-BB72 for press-fit. For other shell standards, ask us which Hollowtech II bottom bracket suits your frame. Check frame clearance before you order: 4iiii publishes a printable frame clearance guide for the Precision 3+ pod, and after fitting you should spin the crank by hand and not ride if a pod touches the frame.

Warning: This product contains a button/coin battery. Keep new and used batteries out of reach of children. Swallowing can cause serious injury or death within hours. Seek medical attention immediately if a battery may have been swallowed or placed inside any part of the body.