XRAY RX8 21T Pinion Gear for Tuning - Arrowmax AM-RX8-348521  [AM-RX8-348521]

Aftermarket 21T pinion for XRAY RX8

The Arrowmax AM-RX8-348521 is a 21-tooth pinion made for the XRAY RX8 platform, machined from 7075-T6 aluminium and finished with a hard coat. It serves as a direct second-stage replacement for RX8 cars where changing tooth count adjusts the effective gear ratio and motor loading.

Key points hobbyists should note:

• Material and finish: 7075-T6 aluminium with a hard-coated surface to reduce wear from spur engagement.
• Role in drivetrain: installed as the 2nd-stage pinion to shift final drive ratio and trade off acceleration against top speed.
• Compatibility: built for the XRAY RX8 series; always confirm RX8 pinion geometry and shaft dimensions before fitting.

Fitting and gear tuning tips

When changing pinions, confirm correct mesh with the spur gear and tighten the set screw to the RX8 motor mount torque specification. Inspect and remove any machining residue before first use and re-check mesh after an initial break-in. Swapping across the 16T-21T range produces predictable RPM and drivetrain load differences, so adjust ESC settings and gearing choices accordingly.