Reedy Sonic 540-M3 Spec Rotor 12.3 X 7.25 X 25.3

The Reedy Sonic 540-M3 Spec Rotor (Part No: AS286) is a precision tuning component designed specifically for the 540-M3 brushless motor series. This particular rotor is the factory-standard for the 25.5-turn ROAR Spec motor, but it serves as a critical option part for racers looking to swap power characteristics. By choosing this specific 12.3mm diameter, drivers can trade off top-end RPM for increased low-end torque and better braking feel.

Key Features:

• High-Strength Sintered Magnet: Features a premium sintered neodymium magnet that maintains high magnetic flux even under the extreme heat of a 5-minute racing main.
• Precision Balancing: Each rotor is factory-balanced to eliminate high-speed vibrations, which reduces bearing wear and ensures maximum RPM efficiency.
• Laser-Etched ID: The rotor is clearly laser-etched with its dimensions and part number (AS286), allowing for instant identification during technical inspections at ROAR or IFMAR sanctioned events.
• Tuning Versatility: The 12.3mm diameter provides a "middle-ground" feel—offering more "grunt" out of corners than a 12.0mm rotor while maintaining better heat management than a massive 12.5mm torque rotor.
• Complete Installation Kit: Typically includes the necessary shims and O-rings to correctly set the motor's "end play," ensuring the rotor sits perfectly centered within the magnetic field.

Technical Specifications:

Expert Tuning Tip:

Rotor diameter is one of the most effective ways to "gear" your motor internally. Pro-Tip: If you are racing on a small, technical track with many jumps or tight hairpins, this 12.3mm rotor will help the car "pop" out of corners better than the high-RPM 12.0mm version. However, if you're on a massive outdoor track with a long straightaway, the smaller 12.0mm rotor (AS271) might give you the edge in top-speed "rollout."

Tech Note: When installing a new rotor, always check your End Play. There should be a tiny amount of fore-and-aft movement (about $0.1mm$ to $0.2mm$) of the shaft when the motor is fully assembled. If it’s too tight, you’ll burn out the bearings; if it’s too loose, the magnetic sensor (Hall Effect) may provide inconsistent timing signals.