Stock Class Regulations
Sections in red were added (2026/5/11)
6. Modifications (Stock Class)
The stock class follows the Official Regulations, but with the below alterations to section 1-6 Modifications. Refer to the Official Regulations for all other areas.
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. Cutting and shaving down of the chassis is not allowed. Homemade chassis are also prohibited.
- 2. Any additional parts are limited to Tamiya Mini 4WD, R/C Mini 4WD, and Dangun Racer parts.
- 3. Modifications to parts other than the body are also prohibited. However, existing holes in FRP/carbon plates and chassis may be countersunk. Shafts may be pushed through wheel holes.
- 4. Body modifications are limited to shaving it down, and cutting away parts which are an obstruction. Body catch parts must be used.
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5.
Rollers may not be used in the combinations outside of those permitted under the regulations.
(e.g. Putting plastic rings on other rollers, changing a roller’s plastic ring, using different roller sizes.) - 6. It is prohibited to attach HG aluminum setting board, setting gauge and pinion puller parts onto a car.
- 7. Drive gears must be used in combinations permitted by the regulations. Permitted pinion gears depend upon the chassis used.
- 8. Battery terminal parts must be kit-standard, or Grade-Up parts installed as instructed in their manual. Soldering and use of double terminals is not allowed.
- 9. Modifications must not pose risk of hand injury or track damage. Grease must not be allowed to dirty the course.
- 10. Batteries must be installed in the correct polarity and direction.
- 11. Plates must be securely fitted. They must not wobble.
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12.
The area between the front and rear shafts and bearings/eyelets, plus the rear halves of the front wheels and the front halves of the rear wheels (the whole width of the tire) are designated a “forbidden zone.” This is the red area in the images below.
Only bodies (and driver figure) may be attached in the “forbidden zone.” No other parts may be attached, whether they are completely in the zone, or only partially. - 13. Parts which touch (or could conceivably touch) course walls must be fixed to the chassis or to a plate which itself is affixed to the chassis. The only exceptions are for parts which require motion: wheels/tires, rollers, and components in mass dampers and sliding dampers.
Forbidden Zones Visual Reference
Stock class Forbidden Zone (red zone): side view
Stock class Forbidden Zone (red zone): plan view
Stock class Forbidden Zone (red zone): overview
Zones forbidden under Official Regulations (blue zone): side view
Zones forbidden under Official Regulations (blue zone): plan view
Zones forbidden under Official Regulations (blue zone): overview
Stock Class FAQs
| Theme | Question | Answer |
|---|---|---|
| Motors | Motors Can I use Dash motors? | Yes |
| Motors Can I use parts from disassembled motors? | No | |
| Bodies | Bodies Can I use clear or polycarbonate bodies? | Yes |
| Bodies Can I split bodies into multiple pieces? | No. The only alterations permitted are shaving bodies down or cutting away parts that are an obstruction to parts. | |
| Bodies Can I cut away sections that obstruct chassis attachment, in order to move the body onto a different chassis? | Yes | |
| Bodies Do I have to attach driver figures and rear wing parts? | No, you may remove them. | |
| Bodies Will I be disqualified if a driver figure falls off during a race? | No | |
| Bodies Will I be disqualified if body parts (wing, etc.) fall off during a race? | No | |
| Bodies Do I have to cut off all unused parts from a polycarbonate body? | You must cut your body as instructed in the kit manual. | |
| Chassis | Chassis Can I reverse chassis direction? | No |
| Chassis Can I make new screw holes? | No | |
| Chassis Can I countersink existing screw holes? | Yes | |
| Chassis Can I drill through screw holes or widen them to 2mm? | Yes | |
| Chassis Can I use combinations of chassis and A parts that are not specified? | Yes | |
| Chassis Can I race without the battery holder attached? | Yes | |
| Ball Bearings | Ball Bearings Can I use ball bearings? | Yes |
| Tires / Wheels | Tires / Wheels Can I combine tires and wheels of different sizes? | Yes |
| Tires / Wheels Can cut or shave down tires? | No | |
| Rollers | Rollers Can I use rollers which have worn down to a smaller diameter? | Markedly small rollers are forbidden. Follow staff instructions at inspection. |
| Rollers Can I replace the ball bearing in bearing rollers? | No | |
| FRP & Carbon Plates | FRP & Carbon Plates Can I reinforce plates using cement? | Yes |
| FRP & Carbon Plates Can I cement multiple plates together? | Yes | |
| FRP & Carbon Plates Can I use carbon plates? | Yes | |
| FRP & Carbon Plates Can I attach plates loosely? | No | |
| FRP & Carbon Plates Can I taper down plate edges? | No | |
| Mass Dampers | Mass Dampers Can I widen mass damper holes? | No |
| Mass Dampers Can I use mass dampers whose holes have widened through use? | Markedly oversized holes are forbidden. Follow staff instructions at inspection. | |
| Mass Dampers Will I be disqualified if a mass damper with ball connectors falls off during a race? | No | |
| General | General Can I use discarded sprues or offcuts from polycarbonate or clear bodies? | No |
| General Can I use Mini 4WD Car Catcher parts on my car? | No | |
| General Can I heat brake sponges to alter them? | No. This is dangerous and strictly forbidden. | |
| General Can I cut brake sponges? | Yes | |
| General Can I cement shafts into gears? | Yes |
