BOX STOCK CLASS REGULATIONS

DRIVER RESTRICTIONS

Lipo 3500, 2wd Mod, AWD Mod, Lipo 2500 Pan, or Open Pan drivers are not permitted in Box Stock class.

CHASSIS

Allowed: Kyosho MR03S, MR03S2, MR03 RTR, MR04 RWD, Associated SR27 (RWD only)

Not Allowed: Shaving chassis or removing sections for weight reduction

Chassis must be raced as manufactured from the box

WHEELBASE

Only allowed wheelbases: RWD 90mm, 94mm, 98mm, and 102mm

MOTOR & ESC BOARD

Kyosho MZ9P, MZ9E Motor from RWD RTR

Permitted modifications:

Changing motor wires with same or maximum (20) gauge wire

Removing safety switch

Motor must be run as manufactured with no other manipulations or modifications

Not Permitted: EVO Board or other upgraded board

GEAR RATIO

6T - 9T Pinion (included with RTR kits)

Stock Kyosho Gear Diff only

WHEELS

All brand plastic and aluminum 1/28 scale production wheels allowed

Size limitations:

Maximum front-wheel width: 8.5mm (not including outer flange/disk)

Maximum rear-wheel width: 11mm (not including outer flange/disk)

Maximum wheel diameter: 20mm

Minimum wheel diameter: 19mm

Wheels must be original designs made for 1/28 scale cars

Wheel and tire must fit inside the body

TIRES

Maximum tire diameter (mounted): 25.5mm

Front tires must be 8.5mm and rear tires 11mm

Not Allowed:

Traction compound on tire or race surface

Tire warmers

Homemade tires

Foam tires

Silicon tires

Urethane tires

Ethyl Carbonate tires

Tire inserts

Tires may be cleaned with 70% alcohol solution or water

Using illegal tire cleaner will result in penalties

Direct tire-related questions to the driver's meeting or race director

BATTERIES

Cars must be powered by 4 AAA batteries

Allowed types: Alkaline, Ni-MH, or Ni-Cd

An additional battery is allowed only for transponder connection

ELECTRONICS & TRANSMITTER

Stock Radio from RTR Kit

Only Kyosho original items included in the RTR box are allowed

No modifications to radio permitted

BODY

Any manufactured molded hard shell that fits the allowed wheelbase

All parts must be original for that body

Limited wheel and ground clearance modifications allowed

Size limitations:

Maximum body length: 180mm

Maximum width: 83mm

Not Allowed:

Shaving/thinning body material for weight reduction

Lexan roofs, windows, and wings

Headlight requirements:

Original headlight covers must be installed

Headlight buckets may be removed/omitted

Lost headlight covers may be replaced with decal/tape

Taillights and covers may be removed/omitted

Small body parts (mirrors, canards, exhausts, front splitters) may be omitted to prevent racing damage

Wings: Standard rear wings for corresponding hard-shell body may be used with no height limit

Custom aftermarket plastic wings must meet 45mm height limit from ground

OPTION PARTS

Allowed from any manufacturer: bearings, wheel nuts, springs, and T-Plates

Only original Kyosho front and rear suspension parts may be used

No added weight via tungsten, brass, or other materials

MODIFICATIONS

King pin flip allowed, lower pin must be shortened to no damage track