The TRF503 buggy chassis takes IFMAR World Championship veteran chassis TRF511 and builds upon it using Tamiya's extensive racing knowledge and a bevy of new parts. The aluminium lower deck facilitates a long 287mm wheelbase which not only allows the chassis to make light work of undulations, it also improves pitch/roll balance and raises rigidity and durability. The motor sits 5mm closer to the centre line to suppress roll, and has been shifted 10.5mm forward for superior handling stability. Front and rear aluminium bulkheads contribute to the overall lightening of the chassis without subtracting from rigidity, while the suspension is firmed up by glass fibre-reinforced nylon resin front/rear suspension arms and 12-degree aluminium front suspension plate. Both front and rear damper stays are 3.5mm carbon fibre, with the rear adjusting the wing position downwards for improved aerodynamics. The chassis is cushioned by high-capacity big bore aeration dampers. A 39T gear differential utilizes metal gears, and transfers power smoothly via ring type WO universal shafts. To ensure that the chassis maintains optimum balance, ballast weight is included to balance separate battery packs. A polycarbonate under tray and rear wing are also included.
All parts according to Tamiya Guide books, Tamiya manuals and Tamiya parts listings.