17/08/2026
Attn racers🫡
🏁 TURBOTRAX OPEN BOX STOCK
OFFICIAL HOUSE RULES — QUICK CHEAT SHEET
MIX STOCK TAMIYA PARTS
ORIGINAL • STOCK • UNMODIFIED • USED AS DESIGNED
Open Box Stock allows racers to mix stock parts from different eligible regular Tamiya Mini 4WD box kits while keeping the car essentially stock.
1️⃣ STOCK TAMIYA PARTS ONLY
✅ Only original Tamiya parts normally included in regular Mini 4WD box kits are allowed.
✅ Stock parts from different eligible kits may be mixed.
2️⃣ NO UPGRADE OR PERFORMANCE PARTS
❌ Grade-Up Parts
❌ Aftermarket or copy parts
❌ Starter or Advanced Pack upgrade parts
❌ FRP or carbon parts
❌ Mass dampers
❌ Performance rollers or similar upgrade parts
3️⃣ PARTS MUST REMAIN STOCK AND UNMODIFIED
❌ No cutting, drilling, sanding, shaving, reinforcing, or other modifications unless specifically allowed by these rules.
🔧 REPAIR EXCEPTION: Adhesive may be used only to repair a cracked or slightly damaged screw hole.
The repair must restore the hole to its original function. It must not reinforce an undamaged area, alter the part’s original shape, or provide a performance advantage.
4️⃣ USE PARTS AS DESIGNED
✅ All parts must be installed according to their original purpose, design, and intended position.
❌ No stacking
❌ No repurposing
❌ No unusual mounting
5️⃣ STANDARD CHASSIS INTERNALS
✅ Each chassis must use the proper standard internal components intended for that chassis.
6️⃣ WHITE-BELL STOCK MOTOR ONLY
✅ Motor break-in is allowed.
❌ Opened, tampered, or modified motors are DISQUALIFIED.
7️⃣ FOUR-WHEEL DRIVE ONLY
✅ The car must operate as a proper four-wheel-drive Mini 4WD.
8️⃣ WHEELS AND TIRES
✅ Stock Tamiya box-kit wheels and tires may be mixed.
✅ All four wheels must be the same size.
✅ All tires must have the same size and profile.
✅ Different stock tire types or compounds may be used.
✅ Double-sided tape may be used only between the tires and wheels to secure the tires.
❌ Wheels and tires must not be modified.
❌ Double-sided tape must not be used for any other purpose.
9️⃣ ROLLERS
✅ Stock plastic Tamiya box-kit rollers only
✅ Minimum: 4 rollers
✅ Maximum: 6 rollers
✅ If a roller is designed for a rubber O-ring, the O-ring must be installed.
❌ Double plastic rollers are prohibited—even when originally included in an eligible Tamiya Mini 4WD box kit.
🔟 BODY AND COWL
✅ Any eligible original Tamiya box-kit cowl may be used.
✅ Hard cowls may be painted but must remain unmodified.
✅ Polycarbonate cowls must follow the original Tamiya trim line.
✅ All parts belonging to the cowl must be installed.
✅ At least 4 stickers must be placed on the cowl.
1️⃣1️⃣ SPECIFICALLY NOT ALLOWED
❌ Hollow wheel shafts
❌ Reinforced wheel shafts
❌ Hollow propeller shafts
❌ Gold terminals
❌ All ball bearings
❌ Double plastic rollers
❌ Liquid adhesive, except for the limited screw-hole repair allowed under Rule 3
1️⃣2️⃣ PART LEGALITY AND INSPECTION
⚠️ If a part is questioned during inspection, the racer is responsible for proving that it is an eligible stock Tamiya box-kit part.
Please review these Official House Rules before assembling and submitting your Open Box Stock car for inspection.
BUILD YOUR BEST STOCK TAMIYA.
MIX. TUNE. RACE. 🏁
