Tamiya 42391 TRF421X Chassis RC Kit

This R/C model assembly kit creates the 2 belt-driven 4WD TRF421X, the latest model in the line of TRF chassis; it has been tuned based upon racing feedback, and offers superior drivability and cornering performance. Its double deck layout is composed of a 2mm thick aluminum lower deck and carbon fiber upper deck. With a new motor mount, the kit enjoys a lower center of gravity and optimized flex. Fine-tuning of suspension material gives stability in high temperatures or on high grip surfaces, in conjunction with 1.2mm and 1.3mm stabilizer bars. New knuckle arms’ front Ackerman position gives more direct steering, while the hole on the rear arms moves adjuster rod attachment positions backward for optimum grip on low traction surfaces. Drive shafts have swing shaft caps with ball bearings to limit friction and speed loss.

New Features

• Aluminum Motor Mount: Motor attachment position is 1.04mm lower than that of the TRF421 chassis kit for a lower center of gravity and more stable cornering, and a contemporary design ensures exact assembly.
• 2.0mm thick aluminum lower chassis deck: The new lower deck is made of aluminum. It allows lower motor attachment position for optimal balance, chassis flexibility and weight distribution. NOTE: Compatible with standard TRF421 chassis if the new aluminum motor mount is used in conjunction.
• Upper Chassis Deck: Both types (one-piece and two-piece) of upper deck shape are updated for improved chassis flexibility. NOTE: Compatible with standard TRF421 chassis.
• One-piece upper deck attachment: Tubes, dedicated titanium low button-head screws and shims are used to attach the one-piece upper deck. Adjust flexibility by using 0-0.3mm shims. NOTE: Compatible with standard TRF421 chassis.
• Upper and lower suspension arms (new material) & front and rear damper stays: A- Damper attachment positions are moved 1.0mm toward the inside with new front and rear damper stays. B- Both upper and lower suspension arms are molded in carbon reinforced nylon (the TRF421 chassis kit features glass reinforced nylon) to ensure suspension flexibility and to improve stability on hot temperature or high grip or carpet surfaces. NOTE: Compatible with the standard TRF421 chassis kit when changing both damper stays and suspension arms.
• Drive shafts & drive train: A- New front double cardan drive/joint shaft and rear lightweight aluminum universal shafts feature bearings (Drive shafts used on the TRF421 chassis kit feature swing shaft caps.) to limit friction. B- The design and materials of front direct spool cups and rear differential are changed. (Materials are changed from aluminum to steel.
• Upper arm mounts: New upper arm mounts feature 1mm narrower pivot attachment width for improved cornering response, and upper arm attachment with bushings to adjust pitch. A modern design helps ensure exact assembly and stability under vibration. NOTE: Compatible with standard TRF421 chassis.
• Knuckle arm: New knuckle arms feature new hole positions for front and rear, respectively. The hole for front makes Ackerman position outward for more direct steering and the hole for rear makes adjuster rod attachment positions backward for best rear grip on low or middle traction surfaces. NOTE: Compatible with the standard TRF421 chassis kit. When using knuckle arms included in the TRF421 chassis kit, 4 setup options (2 choices for front and rear respectively) are available depending upon road surface and driving style.
• Stabilizers (sway bars): Precision stabilizers can be chosen from 1.2 diameter (x2) and 1.3 diameter (x1) depending upon road surface and driving style. NOTE: Compatible with the standard TRF421 chassis kit.
• Receiver weight & battery weight: Newly added receiver weight (20g) and 0.6mm thick battery weight (30g) ensure best weight balance. Receiver weight is attached by one screw and works as cooling fan mount. NOTE: Compatible with the standard TRF421 chassis kit.

Features

• 2.0mm aluminum lower deck 
• Aluminum motor mount for low center of gravity 2.0mm carbon fiber upper deck (1- and 2-piece types) 
• Carbon fiber-reinforced plastic upper & lower arms Front damper stay mount 
• Rear damper stay mount Double cardan drive shafts (ball bearing type) 
• Lightweight aluminum swing shafts (ball bearing type) Front direct cups (ball bearing type) 
• Steel gear differential joints (ball bearing type) 
• Upper deck flex sleeve 

Requires

• Body 
• Brushless motor 
• Tires 
• Wheels 
• 2-channel R/C system with ESC 
• Battery pack & charger 
• Batteries for transmitter
• Upper deck titanium 3x6mm screws 
• Knuckle arms 
• 1.2mm stabilizer 
• Receiver weight (20g) 
• Battery weight (30g)

• Length: 397mm (without body) 
• Width: 187mm 
• Wheelbase: 257mm 
• Double deck frame with 2.0mm aluminum lower deck & selectable1- and 2-piece 2.0mm carbon fiber upper decks 
• Transverse motor, 2-belt driven 4WD 
• Front direct coupling, rear oil-filled gear differential 
• 3-piece steering tie-rod 4-wheel independent double wishbone suspension 
• TRF Ultra Short Big Bore (USBB) dampers

Download Product Manual