BOX STOCK

Build the kit as supplied and race it without performance upgrades.

CLASS PHILOSOPHY

Assembly quality, straightness and driving preparation—not purchased upgrades—decide the result.

✅ ALLOWED

→The exact chassis, body, wheels, tires, gears, rollers and normal motor supplied in the kit.
→Kit grease and normal assembly consumables used according to the instructions.
→Painting, decals and cosmetic finishing that do not change performance or dimensions.
→Replacement of a damaged component with the same Tamiya part, geometry and material after official approval.
→Basic cleaning, alignment and screw tightening before inspection.

⚠️ ALLOWED WITH CONDITIONS

→A replacement body, chassis or wheel color is allowed only when it is the same mold, material and specification and is approved before race day.
→Minor body trimming is allowed only when the kit instructions require it or an official confirms it is necessary for normal fitment.

❌ NOT ALLOWED

→Starter-pack, advance-pack or Grade-Up performance parts.
→Changing the motor, gear ratio, roller type, bearing type, wheel type or tire compound.
→Cutting, drilling, countersinking, sanding, shaving, stretching or piercing race-car parts.
→Adding weights, dampers, brakes, plates, stabilizers, tape-based tuning or extra rollers.
→Mixing parts from another kit to create a performance advantage.

SCRUTINEERING

CLASS INSPECTION

1Kit identity and chassis/body pairing

2Supplied normal motor and stock gear ratio

3Stock wheels, tires and rollers

4No added tuning parts or modified components

5Body securely attached and car within general measurements

OFFICIAL DECISION

Rulebook v1.0 applies from 30 July 2026. A configuration not explicitly described must be shown to the race director before inspection. Approval at one event does not automatically create a permanent rule.

VIEW MOTOR MATRIX OPEN BUILD GUIDES