Tamiya 9803567 - Damper Piston 42391 TRF421X  [9803567]

Damper piston for TRF421X

This Tamiya spare part is the damper piston referenced as part 42391 and is intended for use with TRF421X shock assemblies on Tamiya scale RC cars. The component functions as the internal flow metering element inside the shock body, so it directly affects damping response and rebound characteristics when paired with appropriate oil and shock length settings.

The piston is supplied as a replacement component for maintenance or selective tuning of the TRF421X suspension; installers should verify part numbers on their shock assemblies before ordering to ensure direct fit. When servicing shocks, inspect piston surfaces and shock shafts for wear and replace damaged seals or spacers according to the shock rebuild routine relevant to the TRF421X kit.

In practical tuning use, swapping pistons or changing piston orientation alters oil flow and can refine mid‑speed and low‑speed damping behaviour without modifying the shock body or spring rates, making the piston a useful part for iterative setup changes on-track.