These Specifications are the specifications for 2019. There is a clarification in the Wheels section below, highlighted in bold.
1. WIDTH: Overall width of the car, including wheels, shall not exceed two and 3/4 inches (2.75"). The body width where the axles attach to the wheels shall not be less than one and 3/4 inches (1.75").
2. LENGTH: Overall car length may not exceed seven inches (7.00"). The kits often supply wood blanks longer than 7 inches.
3. HEIGHT: Overall car height may not exceed three inches (3.00"). This prevents tall cars from crashing into the finish line and electronic lane judge.
4. WEIGHT: Total weight of the car shall not exceed five (5.000 oz) ounces. (Verified by certified scale)
5. WHEELS: Only official Boy Scout Grand Prix racing wheels are allowed. All four (4) wheels must be used. Wheels may not be altered (rounded across the tread-surface, narrowed etc.) except for the removal of burrs. Wheels may not be lathe-turned, thinned, sawed, perforated or machined in any way. Outside wheel diameter should be no less than 1.175". Ready-made modified wheels are not allowed. Wheels must be attached so that there is a minimum of .375" (3/8") between the car bottom and the rolling surface to provide track lane-guide clearance. Color wheels (Red, Yellow, Orange, Blue and the original Black) are all legal wheels as long as they are the official "BSA PINEWOOD DERBY" wheels. Cubs may correct wheel hubs and axle openings using hand tools and jigs. Only the wheels of a pinewood car may touch the surface of the track and the associated lane guide. If a vehicle fails its "wheels inspection" and they are removed to be replaced, the axles will be subject to closer inspection to confirm compliance with the rules. The inside of the wheel must be visible for inspection from the bottom of the car. If a air dams are used, they must be removable or allow for the judges to inspect the thickness of the wheels and hubs per the above requirements.
6. AXLES: Only official BSA Grand Prix Pinewood Derby metal "nail" type axles are permitted. Axles may be polished and lubricated but the use of wheel bearings, washers or bushings is strictly prohibited. Paper label 'hubcaps' may be used but the head ends of the axles must be made available for judging when requested. Precision machined axles, notched axles, and axles of alternative metals (like stainless steel) are not permitted.
7. LUBRICANTS. Only dry lubricants such as graphite, graphite with Molybdenum, or BSA "AXLE LUBE" are allowed. Oils or other wet lubricants are not permitted, even if sold at the Scout Shop.
8. SPRINGS: The car shall not ride on any type of spring or other suspension.
9. PROPULSION: The car must be freewheeling and may not contain any type of auxiliary propulsion or utilize any type of starting device. (No jets, rubber bands, magnets, hooks, adhesives, springs, motors etc.)
10. DECORATIVE DETAILS may be added provided they do not exceed the maximum weight and dimensions for the car. (Decals, trim, characters and decorations are allowed if they meet the finished car size and weight rules.)
11. NO LOOSE MATERIALS: The car may be hollowed-out and built up to the maximum weight by the addition of wood or metal. Any additional materials must be securely built into the body or chassis. Mercury shall not be used for weight addition or other construction purposes as it is a health hazard.
12. MATERIALS: Cars must be built using the BSA Grand Prix Pinewood Derby Series Car Kits. Additional metal must be used only for weight addition or decoration. Axles must be mounted into the wood body. No portion of other kits will be allowed except for decorative purposes. Structural strength is gained only from the wood body. No metal frames or metal axle support is permitted.