Tamiya 9803402 Stiffener Nut for TRF420X chassis  [9803402]

Stiffener nut role and fit

This Tamiya 9803402 stiffener nut (part no. 42382) is an RC-scale replacement fastener intended for TRF420/TRF420X hop-up assemblies. It functions as a securing element for chassis stiffener components, helping to maintain intended preload and alignment when adjusting chassis rigidity. The description focuses on compatibility and tuning role rather than dimensional data.

In practice the stiffener nut is used where the chassis layout requires a locking or reinforcing fastener for a stiffener plate or brace. When you change stiffener plates, add reinforcement inserts, or experiment with chassis flex, this nut keeps the assembly location secure, preventing unwanted movement that can affect handling balance. Use standard workshop practice for tightening, avoid over-torquing near composite or thin aluminium parts, and inspect mating threads and seating surfaces when reusing hardware.

For hobbyists performing tuning, this nut is a component-level part: it affects the mechanical connection points rather than altering suspension geometry or electronic settings. Keep spare common fasteners and check for thread wear when swapping hop-ups frequently.