TRF421X Damper Piston 42391 - Tamiya 9803567  [9803567]

TRF421X Shock Damper Piston Overview

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 acts as the internal flow metering element inside the shock body and directly affects damping response and rebound characteristics when used with appropriate oil and shock length settings.

Supplied as a replacement for maintenance or selective tuning of 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 rebuild routine for the TRF421X kit.

In tuning practice, swapping pistons or changing piston orientation changes oil flow and can refine mid-speed and low-speed damping behavior without altering the shock body or spring rates, making the piston useful for iterative setup changes on track.