A black 4iiii Ultegra FC8100 Precision 3.0+ Pro Power Meter for bicycles, with dual-sided power measurement crankset and branding visible.
A black 4iiii Ultegra FC8100 Precision 3.0+ Pro Power Meter for bicycles, with dual-sided power measurement crankset and branding visible.

4iiii

4iiii PRECISION 3+ PRO Shimano Ultegra R8100

£875.00 £825.00 Sale

Dual-sided Ultegra R8100 power measurement with left/right balance, advanced pedalling metrics, ±1% accuracy and Apple Find My.

Crank Length: 165
Chainrings: 50-34T
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Key Benefits
  • True Dual-Sided Data — Measures output from each leg independently.
  • Pedalling Analysis — Review left/right balance, smoothness and torque effectiveness.
  • Consistent Measurement — ±1% claimed power accuracy.
  • Indoor and Outdoor Use — ANT+ and Bluetooth Smart connectivity.
  • Low-Maintenance Performance — Up to 550 hours from replaceable batteries.
  • Added Peace of Mind — Apple Find My support for compatible devices.

The 4iiii PRECISION 3.0+ PRO for Shimano Ultegra FC-R8100 brings independent left- and right-side power measurement to road training and racing. With sensors on both sides of the crankset, riders can explore power balance and pedalling efficiency alongside the familiar watts and cadence data.

The system offers ±1% claimed accuracy, ANT+ and Bluetooth Smart connectivity, IPX7 water resistance and up to 550 hours of battery life. Pedal smoothness and torque effectiveness provide further insight for riders looking to understand how they produce power.

Apple Find My support gives compatible Apple users a convenient location feature when the bike is not in use. Select the exact crank length and chainring combination, and confirm compatibility and clearance before ordering.
Technical Specifications
  • Crankset compatibility: Shimano Ultegra FC-R8100
  • Selection: Crank length and chainring combination; verify listed options
  • Measurement: Dual-sided, independent left/right
  • Power accuracy: ±1%
  • Advanced metrics: Left/right balance, pedal smoothness, torque effectiveness
  • Connectivity: ANT+ and Bluetooth Smart
  • Battery: Replaceable CR2032; up to 550 hours
  • Power range: 0–4,000 W
  • Cadence range: 30–170 rpm
  • Water resistance: IPX7
  • Pod profile: 5.5 mm; adds approximately 29 g
  • Apple Find My: Supported with compatible Apple devices
  • Warranty: 3 years
Suggested Use & Compatibility

Best suited to performance road cyclists, racers and coached riders who want independent left/right power measurement and detailed pedalling analysis. Intended for a compatible Shimano Ultegra FC-R8100 crankset configuration; select the exact crank length and chainring option. Confirm bottom bracket/crankset compatibility and clearance on both sides of the frame, especially near wide or flared bottom bracket shells. Compatible with supported ANT+ and Bluetooth Smart head units and training platforms. Apple Find My requires an Apple device.
Why We Choose 4iiii

We choose 4iiii because they’re at the forefront of cycling innovation, delivering world-class power meters and performance technology trusted by both pro teams and everyday riders. Their mission aligns with ours: making advanced training tools accessible, accurate, and reliable for all athletes.

  • Proven Accuracy – +/-1% precision power measurement for trusted performance data.
  • Innovation-Driven – Pioneers in lightweight, compact power meter design.
  • Ride Ready – Durable, weatherproof tech built for real-world cycling conditions.
  • Trusted by Professionals – Used by elite WorldTour cycling teams worldwide.

That’s why 4iiii is part of the North Sports collection — giving riders the tools they need to train smarter, push harder, and achieve their goals.
Crank Length: 165
Chainrings: 50-34T

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