Prepare your Tamiya Cars. This racing season will be epic!

TMAC Stock Class Rules

Stock Class Category Rules and Regulations
All Tamiya cars and parts only.

General Rules

All the parts should be used according to the instruction manual.  Parts cannot be used for other purpose.

No modification to any chassis, body, motor, tire, wheel, battery, and parts can be accepted.  


Only the following motors can be used:

  • 15484 Torque-Tuned 2 Motor
  • 15485 Rev-Tuned 2 Motor
  • 15486 Atomic-Tuned 2 Motor
  • 15487 Torque-Tuned 2 Motor PRO
  • 15488 Rev-Tuned 2 Motor PRO
  • 15489 Atomic-Tuned 2 Motor PRO


  • three sets rollers (6 pcs maximum) can be used from all of our Mini 4WD rollers. Double plastic rollers counted as 1.
  • Aluminum rollers cannot be used.
  • Only Tamiya Original Rollers are allowed (Customization CNC / Anodizing of Colors NOT ALLOWED)


Carbon Plate and FRP plates;

  • All Carbon Plate and HG parts cannot be used.
  • Only two pc maximum FRP plates can be used from all of our Mini 4WD FRP plates. A pair of side plates considered as one (1).
  • Allowable combinations:
    • One Front FRP and One Rear FRP
    • One Front FRP and One pair Side FRP
    • One Rear FRP and One pair Side FRP
  • Aluminum Plates are prohibited.


  • Bearings are prohibited.


  • Poly Carbonate bodies are ok.


The above takes precedence over the following.


  1. Usable Machine Types
    Only Mini 4WD REV, Mini 4WD PRO, Racing Mini 4WD, Super Mini 4WD, Fully-Cowled Mini 4WD, Aero Mini 4WD, Mighty Mini 4WD, R/C Mini 4WD, and Truckin' Mini 4WD machines are permitted. Further restrictions on machine types may be possible depending on the race event or race class.


  1. Machine Assembly
    All machines must be four-wheel drive. Modifications that result in rear-wheel or front-wheel drive are prohibited. Bodies should have stickers applied or be painted, and must be securely attached to the chassis. Please be warned that bodies which are particularly small, or those which it is difficult to check are painted or have stickers applied, may be prohibited. Home-made bodies are prohibited. All machines must go through car inspection and machines that do not pass inspection cannot participate in the race. As a general rule, machines must be assembled by the racer. Some exceptions may be applied. Please ask Race Officials.


  1. Machine Measuring System
    All machines must have a 4WD setup and will be subject to the same measuring system as shown below.

  • Maximum Car Width: Under 105mm
  • Overall Car Height: Under 70mm
  • Overall Car Length: Under 165mm
  • Minimum Ground Clearance: At least 1mm
  • Minimum Car Weight (including batteries and motor): At least 90g
  • Front and Rear Tires: Diameter: 22-35mm, Width: 8-26mm (Note that tires must be attached.)
  • Rollers: Maximum of 6 rollers can be used.
  • Mass Dampers: The installation positions of rotating mass dampers are no longer limited.
  • Only Tamiya Original Rollers are allowed (Customization CNC / Anodizing of Colors NOT ALLOWED)



When adding parts to the bumpers, side guards or the chassis, please note the zone restrictions below.

※Definition of Bumpers - For MS chassis, the bumper is the section on the Front or Rear Unit not including the Bumperless Unit. On other chassis, bumpers are the sections forward and rearward of the front and rear gearboxes respectively.
※Definition of Side Guards - Parts that extend from the sides of the chassis between the front and rear tires.

  • Parts which extend around the outside of the wheels to completely frame the chassis are not allowed.
  • Parts attached to the front bumper cannot extend past the line of the front axle.
  • Parts attached to the rear bumper cannot extend past the line of the rear axle.
  • Parts attached to the side guards must remain within the lines shown: (back edge of Front Tire & front edge of Rear Tire)
  • Chassis: Extension parts which are attached to the chassis itself are subject to the same zone restrictions as similar parts attached to the bumpers or side guards.

    ※There are no rules for parts which pass above or within the outside edges of the tires.
    ※There are no rules for mounting rollers, etc. to the body as long as they are above the level of the wheel axles. If they extend below this line, they will be subject to the same limits as parts which are attached to side guards. 
  1. Motor

Disassembling the motor to change the number of coils and other such illegal modifications are prohibited.  If there are indications that the motor cap has been detached, it will be judged as being illegally modified. 

     5. Batteries  

For official Asia Challenge races, Only Fujitsu alkaline batteries will be allowed!

For other races, alkaline and rechargeable batteries are accepted as long the it is not tampered and follows acceptable standards.

If the battery appears to be damaged in any way, they will not be accepted for safety reasons. Please note that some events may have different rules regarding which types or brands of batteries can be used.


Only kit-included battery terminals or Grade-Up Part battery terminals, installed according to the instruction manuals, may be used. Soldering or double-plated terminals are prohibited. 

  1. Modifications

No modification to any chassis, body, motor, tire, wheel, battery, and parts can be accepted.  Parts cannot be modified or customized. 

Modifications that cause physical harm to the track, cause injury to any person, or release grease and/or other substances onto the track are all prohibited.



Any other questions, please ask the inspectors to settle before the race.

All the drivers should follow the inspectors’ decision.

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