Retrofit legacy AC and IC Classic bikes with threaded spindles using this precision power meter crank. The 4iiii system turns any ride into a data-driven session, tracking left/right power balance, cadence, and normalized power (NP). Its low-profile design preserves original bike aesthetics while adding cutting-edge biometrics ideal for studios upgrading older fleets without compromising on accuracy.

Features:

• Standard threaded spindle compatibility (9/16")

• Real-time torque efficiency measurements

• Crash-resistant aluminum housing

• 5Hz data transmission rate

• Firmware updatable via 4iiii app

• Includes pre-installed chainring bolts

Compatibility:

• Threaded AC models, IC Classic