29/09/2026
OPEN BOXSTOCK Basic Rules
Kits
· Only Tamiya Mini 4wd kits are allowed
· Car must be built following the Specifications based on Cowl/Body used
· GEARS can be replaced to the racers choice but must follow the Tamiya Specified gear ratio.
· Single Shaft
5:1 Blue counter gear + Green spur gear
4:1 Black counter gear + Brown spur gear
4.2:1 Red counter gear + Brown spur gear
3.7:1 Green counter gear + Yellow spur gear
3.5:1 Light Blue Counter Gear + Yellow spur gear
*Dual Shaft
4:1 Blue counter gear + Orange spur gear
3.7:1 Yellow counter gear + Pink spur gear
3.5:1 Green counter gear + Pink spur gear
NOTE:
· Mixing of gears is prohibited
· eyelet on the counter gear are only allowed to specific chassis as instructed by Tamiya. MA/AR/VZ
· MOTOR
· Only Mabuchi or SMC motors intended for Tamiya mini 4wd motors Only
· Only WHITE BELL STOCK MOTOR.
· Must not be modified nor opened.
Note: scuff marks on cap lock, loose motor cap etc. may it be natural or intentional
Are deemed unauthorized there for prohibited.
· ACCESSORIES can or can’t be installed to the racer’s specifications.
- Stickers
- Rollers (must meet minimum required rollers)
- Wing
- Spoilers both polycarbonate and hard cowl
- Skid Plate
- Tail (As long as car meets the minimum number of roller requirements)
· POLYCARBONATE COWLS
· Must be cut according to Tamiya’s instruction manual and as allowed by Brickyard
· can be painted on the inside part of the cowling
· No reinforcement of any kind is allowed
· PLASTIC HARD COWLS
· Outer part may be painted but must retain 70% of natural color
· ROLLERS
· Can be placed to the racer’s specification
- Chassis only
- Rollers intended for body may NOT be placed on chassis and vise versa
· Must have at least Four (4) rollers installed.
· Rubber O-Ring can be installed or removed to the racer’s specifications.
- May only be removed by pair
· No modifications of Rollers
· WASHERS must be installed specified from Tamiya’s instruction manual.
· RACER’S NAME
· must be installed to the under belly of the chassis. Or any part visible
· Can be installed to the cowling
· Must not touch any moving part of the kit..
· CHASSIS
· must not have any modifications including reinforcement, cutting or sanding.
· TIRES
· Must follow Kit Specification based on Cowl used
· can be attached using a paper-thin double-sided tape.
· Hard tires may be replaced with different colors as long as it is a hard tire
· Super hard tires may use print or non-printed as long as it is a Super hard tire
· WHEEL
· Must not be modified or reinforced.
· Can be aligned.
· Must not be sanded, drilled or pierced.
· Must have a gap from the chassis
· Can be marked for alignment purposes
· REPLACING OF PARTS
· must follow the kits Specifications on type and mold based on Cowl used
· May use different colors as long as specifications based on cowl is followed
- Copy Parts
· are NOT allowed
· PARTS
· must be used to its intentions. No alteration allowed.
· REINFORCEMENTS
· are only limited on adding any liquid adhesive inside the screw holes.
· GOLD TERMINAL
· strictly prohibited.
Please Note:
· GT RACER KITS
· MOTOR must be replaced with a white bell motor
· HOP-UP, STARTER and EVO PACK KITS
· May be used, provided that only the base car is used and no accessories such as plates and/or dampers are used.
· Aftermarket and Bootleg kits
· are strictly prohibited. e.g.: auldey, daxing and force labo, etc.
