Stiffener Nut 9803402 Compatible with TRF420X Chassis - Tamiya  [9803402]

Function and chassis fit notes

This Tamiya 9803402 stiffener nut (part no. 42382) is a replacement fastener intended for TRF420/TRF420X hop-up assemblies. It acts as a securing element for chassis stiffener parts, helping to keep preload and alignment stable when you alter chassis rigidity settings. The description stresses fit and tuning role rather than specific measurements.

Typically the nut is used where the chassis layout needs a locking or reinforcing fastener for a stiffener plate or brace. Changing stiffener plates, adding reinforcement inserts, or testing chassis flex all rely on consistent fastener seating; this nut helps prevent unwanted movement that can affect handling. Use appropriate tightening practice, avoid over-torquing near thin aluminium or composite sections, and verify mating threads and seating surfaces before reuse.

From a tuning perspective this nut influences the integrity of mechanical joints rather than suspension geometry or electronics. Keep useful spares and monitor thread condition if you swap hop-ups often.