The 421 is the high-end competitive model by TRF (Tamiya racing factory) and has been designed for the racing tracks of this world. Compared to his predecessor, he has been completely revised at many points. The drive train was moved around 22.7 mm toward the center of the chassis and has drive belts of the same length at the front and rear for stable driving.With the updated configuration of the spur wheel and drive belt, only a special nut is required to attach the spur wheel, WAS increases the efficiency of the maintenance.The new lower deck is smaller than the TRF420X chassis kit to limit ground clearance when the chassis rolls.Together with the longer span of the lower links, the front and rear suspension brackets have also been changed from suspension blocks to suspension balls. Approximately 7 mm longer arm widths limit the swivel width and provide stability when the chassis rolls.This text is machine translated.