Race Classes & Rules
Six classes, from your first race to anything-goes. Tap a class name for the full rules.
Start on the left. Every car is legal in any class to its right.
| Animal | Boxstock | B-Tuned | B-Max | Open | Outlaw | |
|---|---|---|---|---|---|---|
| Kits & parts | Tamiya animal or character driver kits, large tires | Standard kits only. No advanced or starter kits | Tamiya only | Tamiya only | Tamiya only | Any brand |
| Motor | Kit motor | Kit motor | Tuned motors: Rev, Torque, Atomic (incl. Tuned 2 versions) | Tamiya-legal | Tamiya-legal | Any, incl. Ultra & Plasma Dash |
| Bearings | None, kit bushings | None, kit bushings | None anywhere | Yes | Yes | Yes |
| Rollers | Kit rollers | Kit rollers | Plastic, no bearings | Per Tamiya rules | Per Tamiya rules | Any |
| Plates | None | None | FRP & plastic stays | FRP & carbon | FRP & carbon | Any |
| Cutting & drilling | None | None | Holes to 2mm, countersink only | Holes to 2mm, countersink only | Cutting OK; parts must stay identifiable | Any |
| Dampers | No | No | Yes | Screw-mounted, no swinging plates | Yes | Yes |
| Big events | Yes | Yes | Local only | Yes | Yes | Local only |
Animal
First race. Kids welcome.
- No bearings
- No plates
- No cutting
- No dampers
- Kit motor
Allowed
- Any Tamiya Mini 4WD kit with a pre-painted animal or character driver and large-diameter tires
- New kits not on the list below: staff make the call at tech
- Built per the kit manual
- Kit motor, kit wheels and tires, kit rollers
- Kit bushings
Not allowed
- Any upgrade part, including parts from special-edition boxes
- Ball bearings
- Added plates or dampers
- Cutting or drilling anything
Known legal kits
| Item # | Kit | Chassis |
|---|---|---|
| 18084 | Panda Racer | Super-II |
| 18086 | Dog Racer | Super-II |
| 18087 | Hawk Racer | Super-II |
| 18088 | Owl Racer | Super-II |
| 18089 | Pig Racer | Super-II |
| 18090 | Cat Racer | Super-II |
| 18093 | Koala Racer | VS |
| 95694 | Year of the Horse 2026 | Super-II |
| 95650 | Year of the Dragon 2024 | Super-II |
| 95678 | Santa Claus | VS |
| 95698 | Santa Claus Red Racer | VS |
Not eligible (small tires): Year of the Snake 2025 (95679), Shirokumakko (18083), Panda Racer 2 (18092).
Boxstock
Standard kit, built from the box.
- No bearings
- No plates
- No cutting
- No dampers
- Kit motor
Allowed
- Any standard Tamiya Mini 4WD kit
- Built per the kit manual
- Kit motor, kit rollers, kit bushings
- Animal class cars
Not allowed
- Advanced or starter kits
- Upgrade parts from special-edition boxes (bearings, plates, tuned motors)
- Ball bearings
- Added plates or dampers
- Cutting or drilling anything
Quick test: if the kit ships with anything beyond basic parts, like ball bearings, a tuned or dash motor, or FRP/carbon plates, it isn’t Boxstock.
Back to the class tableB-Tuned
Your first upgrades.
- No bearings
- No carbon
- No cutting
- Dampers OK
- Tuned motors
Allowed
- Tamiya Mini 4WD parts only
- Motors: Rev-Tuned, Torque-Tuned, Atomic-Tuned and their Tuned 2 versions. PRO-chassis cars use the PRO versions
- Plastic rollers with no ball bearings
- FRP plates and plastic stays
- Dampers
- Enlarging existing holes to 2mm and countersinking
Not allowed
- Ball bearings anywhere: axles, gears or rollers
- Dash motors or faster
- Carbon plates
- Cutting the chassis or adding new holes
- Super FM (SFM) and Carbon Reinforced Super FM (CFM) chassis
B-Max
International no-cut spec.
- Bearings OK
- Carbon OK
- No cutting
- Screw-mount dampers
- Tamiya-legal
Runs Tamiya’s Stock Class / B-MAX GP regulations. The two rule sets were merged in December 2025, so one car can race both. Official Stock Class regulations
Allowed
- Tamiya parts only
- Tamiya-legal motors, ball bearings, FRP and carbon plates
- Screw-mounted dampers
- Enlarging existing holes to 2mm and countersinking
- Cutting the body for clearance (body catches required)
Not allowed
- Cutting the chassis, plates or bumpers, or adding new screw holes
- Swinging or loosely mounted plates
- Cutting or sanding tires; reshaping or drilling rollers
- Motor disassembly
Open
Tamiya official rules.
- Bearings OK
- Carbon OK
- Cutting OK
- Dampers OK
- Tamiya-legal
Runs Tamiya’s Official Mini 4WD Race Regulations. The key idea: you can cut, but every part must still be clearly identifiable as the original Tamiya part. Official regulations
Allowed
- Tamiya Mini 4WD, R/C Mini 4WD and Dangun Racer parts
- Tamiya-legal motors, bearings, FRP and carbon
- Cutting plastic and cutting holes in the stock chassis
- Trimming carbon, FRP and metal parts, and adding or enlarging mounting holes, as long as the part stays identifiable
- Drilling aluminum rollers to lighten them, if they keep their original shape
- Dampers and moving parts
Not allowed
- Non-Tamiya parts or homemade chassis
- Reshaping carbon, FRP or metal parts so the original is no longer identifiable
- Sanding, shaving or reshaping rollers, shafts or pins
- Rollers or parts in combinations Tamiya doesn’t allow
- Motors outside Tamiya’s approved list
Outlaw
No limits.
- Any bearings
- Any plates
- Any mods
- Any dampers
- Any motor
Allowed
- Any brand of parts
- Any motor, including Ultra Dash and Plasma Dash
- Any modification
- Any car that doesn’t fit another class
Still required
- Every-class size, weight and safety rules below
- Nothing that damages the track or puts grease on it
Every class
These apply to every car.
Size & weight
- Width under 105mm, height under 70mm, length under 165mm
- At least 1mm ground clearance
- At least 90g with batteries and motor
Car
- Four-wheel drive only
- No motor disassembly
- Body painted or stickered and securely attached; no wing-only bodies
- Batteries: any AA NiMH (no alkaline or lithium). Interim rule until a single race battery is announced
Track & safety
- No grease or anything that dirties the track
- Nothing that damages the track or can cut hands
Officials
- Race officials have final say on anything not listed
- A car that fails tech must be fixed and re-checked before it races
Big events
Tamiya parts only.
- Classes: Animal, Boxstock, B-Max and Open
- B-Tuned: local races only for now; big-event status to be announced
- Outlaw: local races only