Tamiya 3404174 Upper Deck — Compatible with 42391 TRF421X  [3404174]

Product summary: upper deck for TRF421X

This upper deck is provided as a spare identified by code 42391 for the TRF421X chassis range. It serves the upper mainplate position and is supplied for repair use or for when you want to change chassis flex and balance as part of setup adjustments.

The item is produced to match the TRF421X original mounting arrangement so it works with existing standoffs and fasteners without altering the chassis. When swapping decks, confirm that hole alignment and screw lengths are correct to maintain the intended chassis geometry and to prevent unwanted play or binding.

As a hop-up or spare, the component mainly affects structure and tuning: exchanging deck pieces can shift fore/aft stiffness and thereby influence handling on different surfaces. Keep track of any screws and shims removed during the change to preserve your setup baseline.

Fitment details

Compatible with 42391 TRF421X as specified by the part code and listing.

Good for hobbyists and workshop technicians needing a like-for-like replacement or testing different deck stiffness; the part integrates into the TRF421X platform without modification.