Tamiya’s TRF R/C designers never rest. They are constantly looking to bring our most hardcore R/C racing fans the absolute best features able to be squeezed into a 1/10 scale touring car chassis! After two and a half years of development, we now bring you the ALL-NEW TRF 421. The highest end touring car chassis series we produce has received a whole new suspension and layout makeover! New features: This 2-belt driven 4WD carbon fiber double-deck design is loaded with new features such as an updated drivetrain, a new lower deck shape, front and rear upper A arms, and new shorter dampers, all of which promise to translate into serious speed on the track! Other notable features include a choice between one- and two-piece upper deck layouts for different chassis flex characteristics, plus updated suspension geometry that keeps the chassis more stable. Key Features: The Drivetrain uses a front direct coupling and rear oil-filled gear diff. Equal length front and rear drive belts minimize pitch. Suspension Arms are a rigid "A" design with 7mm longer span compared to the TRF420X for stable roll, while upper arm mounts can be slid to adjust camber. Three damper pivot positions are provided. Dampers are 5.5mm shorter than on the TRF420X, for a lighter chassis and lower center of gravity. Attach them directly to aluminum mounts and fine-tune with spacers. • 1/10 scale R/C chassis assembly kit. • The drivetrain features the motor position moved 22.7mm toward the chassis center compared to the TRF420X Chassis Kit and has identical length front and rear drive belts for stable drivability. • With updated setup of spur gear and drive belts, only one dedicated nut is required to attach spur gear, which enhances efficiency of maintenance. • The new lower deck is smaller compared to the one used on the TRF420X Chassis Kit to limit ground clearance when the chassis experiences roll. • Choose from two types (one-piece and two-piece) of upper deck. Changing screw positions allows five setup patterns in total. • A-shaped suspension arms are employed for higher rigidity. (The 420X chassis kit uses I-shaped suspension arms.) Longer lower arm spans limit swing width and ensure stability when the chassis experiences roll. • Along with longer lower arm spans, front and rear suspension setups are changed from suspension blocks to suspension balls. Roughly 7mm-longer arm spans limit swing width and ensure stability when the chassis experiences roll. • Toe angle can be adjusted by uprights. (The toe angle of lower arm inside is 0 degrees.) • Three attachment damper positions (inner, middle, and outer) on front and rear lower arms are offered by two types of aluminum bushings. • Changing positions of upper arm mounts by screws allows changes to front and rear caster angles, which is suitable for current high-downforce races. Front caster available angles: 3, 4, and 5 degrees. Rear caster available angles: -.5, -1.5, and -2.5 degrees. • Dampers are shorter by 5.5mm compared to the 420X chassis kit, which provides an exceptionally low center of gravity and reduces the weight, for a more dynamic driving experience. • Dedicated damper ends are used front and rear to ensure the same piston level. • New damper oil seals (Item 51738) are used to keep the maximum oil amount and to make use of oil dampers efficiently. • While the 420X chassis kit uses carbon fiber damper stays, this chassis kit employs aluminum mounts for precise angle adjustments based on the number of spacers used. • Front and rear differential pullies are newly molded while direct coupling and oil-filled gear differential are employed at front and rear, respectively. (The currently sold Hop-Up Option and Spare Parts can be used.) • The front features double cardan joint shafts while rear employs lightweight universal drive shafts. New axle shafts (Item 42388) and 45mm drive shafts (Item 42387) are also used for both front and rear to ensure efficient drivetrain and maintenance. • Newly designed lightweight rear wheel axles enhance durability. • Precision stabilizers are attached at a lower position than drive shafts for efficient maintenance of drivetrain. Includes 1.0mm diameter (x1), 1.1mm diameter (x2) and 1.2mm diameter (x1). • The steering system pairs dual steering arms and Ackerman bush with a new steering bridge. Three types of new spacers featuring different diameters allow steering angle adjustment. • Includes Sealed Ball Bearings from the TRF series for efficient rotation and Item 22078 Aluminum Differential Holders (0.8mm Offset, 2pcs.). • The newly molded quick-plate design battery holder does not require tape for attachment. Depending on the battery pack equipped, change positions of spacers and posts. Shorty pack compatible. • Comes with a carrying case dedicated to the TRF421 chassis kit. • Required to complete: 2-channel radio, low-profile steering servo, ESC, 540 motor, wheels and tires, 190mm TC or Sports Car body, 7.4volt battery pack and compatible charger.