Rear Stiffener for TRF421 Models (TRF421X Compatible) - Tamiya 3404177  [3404177]

Rear brace for the TRF421 family

This RC rear stiffener is designed as a hop-up for the TRF421 range to modify rear chassis rigidity and sharpen handling. It affects how the rear end behaves under acceleration, through turns and during traction shifts, letting you tweak balance without touching suspension geometry directly.

Fitment is at the TRF421 rear chassis mount area and installation follows standard hop-up procedures. Because it alters chassis stiffness rather than suspension travel, racers typically pair it with gradual adjustments to shocks, springs or anti-roll bars to achieve the right handling feel.

Practical tuning note: adding the stiffener usually tightens rear traction and cuts chassis flex; it can be useful for reducing oversteer or stabilising the rear at speed, after which you should fine-tune damping and roll centre for a well-balanced setup.