【1】Machines

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.

2. 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. 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. 

3. 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 installations total (double rollers count as 1 installation.)
  • Mass Dampers: Rotating mass damper may not extend from the sides beyond the line formed by the guide roller poles. 

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.


4. Motor


1.     ALL Tamiya motors are permitted.

2.     Disassembling the motor to change the number of coils and other such illegal modifications are prohibited.

3.     If there are indications that the motor cap has been detached, it will be judged as being illegally modified.


5. Batteries    
R6/AA/UM3 batteries are permitted. If the battery appears to be damaged in any way, they will not be accepted for safety reasons.


6. Modifications

Please follow the guidelines below when modifying your car. Also note that for modifications not listed, race officials will have the final absolute authority to grant or deny their use.


  1. Chassis modifications are limited to cutting away plastic material or cutting holes out of the stock chassis. Homemade chassis and homemade parts are prohibited.
  2. Part modifications are limited to cutting away the material or making holes in the stock part.

Gear modifications are limited to making holes or shaving away material to reduce weight and installing ball bearings. All running gears must be installed according to the set gear ratios.

  1. 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.
  2. 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.
  3. Modifications to the tire's shape are allowed if they comply with the Car Measuring System outlined above. However, changing the material properties of the tire surface (including, but not limited to, applying glue or other substances to the tire surface) are prohibited.



3 For Competitions at Official Race Courses

  1. A racer will immediately retire from a race if their car leaves the track, flips over, jumps into another lane, or if their car's body detaches during the race.
  2. If race officials determine that a racer's car is blocking the progress of faster machines, the racer will be required to retire.
  3. A car's race is completed when it reaches the finish line.
  4. Qualifying and Final positions are determined by finishing order.


4 Car Inspection

  1. All racers must have their car inspected by race officials before the race. If any part of the car is determined to be against race regulations, the racer must make the necessary changes in order to participate in the race.
  2. In addition to the pre-race car inspection, other car inspections may occur at any time during the race day at the race official's discretion. If the car is found to be in violation of the race regulations at any of these inspections, the racer's race results up to that point will be disqualified and the racer must make necessary changes in order to participate in subsequent races.


5 Disqualification

If any of the following situations occur, race officials will, at their discretion, have absolute authority to disqualify any racer. Please take care to remember the common manners for a Mini 4WD race to avoid any problems.


  1. A racer's car is determined to have modifications that will cause physical harm to other racers, other cars, or the race track.
  2. A racer's car is determined to have modifications that are designed to deliberately obstruct other cars.
  3. A racer deliberately puts grease or other substances onto the track to affect track surface conditions.
  4. A racer is determined to have deliberately touched the track or cars to impede other racers' race progress.
  5. A racer does not follow the instructions of race officials or otherwise impedes the operations of the race track.
  6. A racer is determined to have acted against the spirit of fair play or caused distress to other participants.


6 Race Operations

  1. Participants may raise objections to the race officials. However, these objections must be made before the next race begins.
  2. Race officials reserve the right to announce the use of special regulations at any time during the race.


7 Participant Restrictions

  1. Please be aware that some races have age limitations, so it may be that some participants cannot take part in certain classes or races.
  2. Except for endurance races, it is against regulations to have more than 2 racers using the same car.