Pack 421’s Pinewood Derby Rules

Last revision: December 17, 2023

For build resources, click here.

GENERAL

  • The car must be built for the current Pinewood Derby Racing Season.

  • No repeats or repaints.

  • Complete cars purchased from a third party are not allowed.

  • The car may not be sent to a third party facility for tuning or other performance enhancements.

  • Each car must be given a name at check-in. Car names can be multiple words but should not exceed 20 characters including spaces. Longer names will be allowed but may be truncated on race displays.


body

  • The main body structure must be made of wood.

  • The car design may be enhanced by the addition of other stable materials such as plastic or metal.

  • Any additions must be firmly attached and meet car size specifications. 

  • The car must be freewheeling.

The car must meet the following specifications:

  • Width: not to exceed 2.75 inches

  • Length: not to exceed 7.0 inches

  • Height: not to exceed 3 inches

  • Weight: not to exceed 5.0 ounces on a scale accurate to 1/10 ounce

IMPORTANT: Car weight is strictly enforced to 1/10th ounce accuracy. It is advantageous to make sure the car weight is as close as possible to 5.0 ounces without going over. If a car exceeds 5.04 ounces at inspection, the Scout will be asked to remove excess weight (using a drill or file if necessary) until the weight is at or below the limit. Note: Most kitchen scales are not accurate enough to measure a derby car properly. Postal scales are more likely to have the required accuracy. Official weight of all cars will be determined by inspectors upon check-in using a single high-accuracy scale to ensure trueness and consistency. Be prepared to make adjustments if needed.

  • Weights: The use of lead weight is strongly discouraged. Zinc, tungsten, brass, or other safe materials are recommended instead. If lead is used, it should be completely sealed and not exposed where it could be contacted by children or race officials. Drilling, cutting, or filing of lead (to reduce excess weight) will not be permitted at the venue due to safety reasons. If coins or other loose items are used for weight, make sure they are securely attached (use strong glue, not tape!), and take special care when placing weights on the bottom of the car to avoid creating obstructions that might interfere with the guide rail or braking.

  • Clearance: The wheels are the only part of the car allowed to touch the track. Cars roll down the track on a center rail that is 1-5/8 inches wide and 1/4 inch tall. The underside of the car should leave a clear path for the rail and avoid having any protrusions or edges that might catch on the rail (see Car Bottom below). Note: If questions arise about a car’s clearance during check in, race inspectors should place the car on the track to verify that only the wheels touch the track.

  • Car bottom: To clear the track rails, the bottom of the car should be no less than 3/8 inch from the surface. However, if the car rolls on the track without touching the rails, the height will be considered legal. Avoid irregular shapes on the bottom of the car. When the car hits the end braking section of the track, it will be sliding on the underbody of the car, not the wheels. If there are notches, grooves, or protrusions, they could cause the car to bounce up and off of the track, possibly injuring itself and/or other Scout’s cars.

  • Fenders: Fenders or other body parts may extend below the car bottom on the sides of the body, but remember the guide rail width so the fenders do not rub.

  • Wheelbase: You may use the precut axle slots in the BSA pinewood block or make new axle holes for a longer wheelbase. Longer wheel bases promote a more stable car path. Wheels may extend beyond the rear of the car, but may not protrude ahead of the starting pin (front edge of the car). The total car length including the wheels may not exceed 7.0 inches.

  • Front Edge of Car: When placed in the starting position, the front edge of the car will rest on a retractable starting pin that protrudes upward from the center of the track. No part of the car (including the front wheels) may extend forward beyond the starting pin. The front edge of the car should be at least 1⁄2 inch wide at the center of the car. This recommendation ensures the car rests securely against the starting pin when placed in the starting position and is wide enough to trigger the electronic timer. A needle nose car will be permitted to race, however its performance will suffer because the nose will not trigger the electronic timer accurately. If you choose to run a needle nose car, the electronic time, even if it is slower than the car’s actual time, will be the official time.

The following items are prohibited:

  • Springs

  • Magnets

  • Starting devices or propellants

  • Electronic or lighting devices that make sound or interfere with the race electronics. (Decorative lights that do not interfere with race electronics are permitted. But note that you will not have an opportunity to turn them on or off after check-in. Make sure the battery is turned on prior to check-in and can last through the end of the race.)

  • Liquids, wet paint, oil, sticky substance, or powders of any kind (other than axle lubrication)

  • Glass or excessively fragile parts

  • Wheel/Axle bearings, bushings, and washers

  • Loose objects on car


Wheels

Only official BSA wheels are allowed. Official BSA colored wheels (available from Scout Shop and other suppliers) are allowed, but make sure they are official BSA wheels.

  • All lettering and numbering on the outside and inside of the wheel must remain complete and visible for inspection.

  • The decorative spokes and fluting (small dots) on the outside of the wheel must remain visible and complete around the entire circumference of the wheel.

  • The outer tread surface (the flat part that touches the track) may be sanded, shaved, or polished to remove imperfections and to true roundness, but the tread must be flat and parallel to the wheel bore. Therefore, the following modifications are prohibited: Rounding of the tread surface, Grooving, H-cutting, or V-cutting the tread surface.

  • The inside edge of the wheel may be trued and smoothed to ensure straightness, but the width of the tread surface must be at least 6.5mm. This rule is only in place to prevent extreme narrowing of the wheel tread width. Wheel tread width will not be measured unless a wheel has been noticeably and significantly narrowed.

  • Lathing or removing material from the inner surfaces of the wheel is prohibited. Wheels will be checked for this during inspection. Wheels in violation can easily be detected due to having thinner than normal plastic thickness and/or non-standard machine marks (grooves or step edges) on the inner surfaces. Cars with illegally modified wheels will not be allowed to race in the Pack Championship Series or Open division, but may be entered in the Outlaw division.

  • Drilling holes in the sidewall or tread of the wheel is prohibited.

  • Wheel bore treatments are allowed, including polishing, waxing, sanding, and/or tapping. However, filling and re-drilling the wheel bore—or narrowing the wheel bore in any other way (e.g., bushings, bearings, etc.)—is prohibited.

  • Washers, air shields, and air dams between the wheel and car body are prohibited.

  • The inside cavity of the wheel may not be filled with any material except small amounts of fingernail polish for balancing.

  • Accent paint on wheels is permitted but should be avoided on contact or friction surfaces. Stickers and decals should not be attached to wheels or axles.

Common legal modifications include, but are not limited, to the following:

  • Truing the outer tread surface to correct out-of-round wheels (but do not remove so much tread material that any of the decorative fluting or dots on the sidewall is removed).

  • Truing and shaping the inner edge of the tread surface to get smooth straight edges (but do not remove so much edge material that the tread width is reduced to less than 6.5mm).

  • Applying wheel bore treatments such as polish and wax to smooth the bore.

  • Truing or coning the tip of the inner hub and/or removing the step on the outer hub.

  • Balancing the wheel by adding a small amount of material such as fingernail polish to the inside of the wheel.

Number of wheels:

  • At least 3 free-spinning wheels must be attached to the sides of the car body using a legal axle.

  • If you choose to run with only 3 wheels, then a guide fin (or similar contrivance) must be used in place of the 4th wheel to ensure the car is prevented from bouncing out of its lane.

  • If you choose to run with 4 or more wheels, it is only required that 3 wheels touch the surface of the track.

  • Wheels (and guide fin if present) should be positioned with wide enough separation and protrusion below the bottom of the car to ensure that they engage the track’s center guide rail sufficiently to keep the car in its lane. If there is doubt during check-in, the car should be tested on the track and if necessary the Scout may be asked to make modifications.

  • You will not have an opportunity to adjust wheel alignment during the race. Make sure all wheels are properly adjuster prior to check-in.


AXLES

  • Metal axles with a nail head are required.

  • You may use official BSA axles or after-market nail type axles from various vendors.

  • You may also polish and groove the axle.

  • Axles may be bent or canted, but the resulting wheel angle shall not exceed 20 degrees from vertical. This rule is to prevent the wheel from binding on the center rail and to prevent the car from exceeding the maximum width limit. In practice, wheel angle will not be measured unless it appears to be significantly angled.


Lubrication

  • Dry lubricant is recommended, but you may sparingly use liquid lubricants as long as they don’t drip.

  • Lubricants you may use include but are not limited to: Graphite, Teflon, Nyoil, and Krytox.

  • Over application of lubricant, which results in excessive shedding onto the track is not allowed. If your car is shedding excessively, it may be disqualified. We will make every effort to race all cars so if there is a shedding car, we will try to figure out how to race it without negatively affecting the conditions on the track for other racers.

  • Make sure lubricant is applied prior to check-in. There will be no opportunity to reapply lubricant during the race, including between heats or divisions.


Race Day

  • Each car must pass inspection before it will be allowed to compete. Scouts will be allowed to correct any rules violations discovered prior to check-in, provided the rework can be completed prior to the close of check-in. Any car found to be in violation of the rules after the race has started shall be disqualified.

  • Any adult or scout may appeal the findings of the Inspectors or other Race Officials to the Race Committee Chairperson, whose decision is final.

  • The Race Committee Chairperson may grant limited waivers or exceptions to rules if he/she determines (after consultation with other race officials) that there is no meaningful impact to the fairness of the race.

  • After a car has passed inspection, only race officials may handle the car.

  • After check-in, car repairs are not allowed unless authorized by the race officials.

  • Typically, race officials will authorize a car repair if it was involved in a collision with another car or object. However, the decision to allow a repair is left entirely to the discretion of the race officials and may be subject to time limits set by race officials. The weight of the car after repair should not materially exceed the weight at check-in (in judgement of race officials), and in no case may a repaired car exceed the regulation weight or dimensional limits.

  • If a car fails to successfully complete a run down the track for any reason, the car will be assigned a time of 9.999 seconds and the heat will not be rerun (see exception for interference below). The slowest heat for each car will be dropped from calculation of its final score, so a single incomplete run will not significantly impact the car’s overall standing in its division.

  • If a car (or part of a car) leaves its lane and interferes with another car, the heat will be rerun. If the same car causes interference again, the heat will be rerun once more without the offending car on the track, and the offending car will be assigned a time of 9.999 seconds. If the car repeatedly causes interference over multiple heats in different lanes, it may be disqualified at the discretion of race officials.


Pack Championship Series
🏁🏎💨

The Pack Championship Series shall be conducted in two rounds: a Qualifier round with divisions by Scout rank, and a pack Grand Final round with the fastest cars from the qualifiers.

Divisions & Grand Finals

The Qualifier Round shall be organized into divisions by Scout rank: Lion, Tiger, Wolf, Bear, Webelos, and Arrow of Light. Each scout shall be entitled to enter exactly one car in his/her division. Any division with fewer than 3 entries may (at the discretion of the Race Committee Chairperson) be merged into the next higher or lower division.

  • The 1st, 2nd, and 3rd place finishers in each qualifying division shall receive an award.

  • The top 8 cars across all Qualifying Divisions shall advance to the Pack Championship Division where they will race against each other to determine the Overall Pack Champion. If a qualifying division fails to have at least one car place in the top 8, then the fastest car from that division shall be added as a wildcard to the lineup for the Grand Final round. Based on results of the Grand Final round, an award shall be given to the Pack Overall Champion and the 1st and 2nd Runner-ups.

  • Each division shall race enough heats to ensure that each car races one time in each lane. A car’s final score will be the average of its times, dropping the time from its slowest heat.


OPEN DIVISION

  • Siblings and friends age 11 and under who are not registered scouts in the pack may participate in the Open Division. One car per person.

  • Cars in the Open Division must comply with all pack rules concerning car construction.

  • Heats in the Open Division shall be conducted the same way as the Pack Championship Series. The 1st, 2nd, and 3rd place finishers shall receive an award. Cars in the Open Division are not eligible to advance to the pack Championship Division.


OUTLAW DIVISION

Moms, Dads, Brothers, Sisters, and Scouts can enter!

  • The no-rules race is just that... no rules... well, almost no rules. You can’t use fire or combustion of any kind. So, no bottle-rocket-powered cars. Other than that, the weight limits, wheel, axle, size, etc. rules don’t apply, except as noted below.

  • Limit one outlaw car per person. Rerunning cars from previous years is discouraged, but may be allowed by the Race Committee Chair in special cases (e.g., vintage car exhibition).

  • The car shouldn’t be taller than about 6 inches (it won’t fit through the finish line timer), and it shouldn’t be longer than about a foot (it won’t fit on the track in the start section). The car must not encroach on other lanes or cause a danger to other cars or the track.

  • Weight should not exceed 16 ounces to prevent damage to the braking section of the track. Liquid weights and fragile parts should be avoided. Lead weight, if used, must be securely enclosed to prevent contact by scouts or race officials.

  • Cars with motors or fans are okay as long as they won’t damage the track or put anyone in danger. You will not be permitted to handle your car after inspection or between heats, so make sure any electronics and mechanical mechanisms are enabled before check in. Electronic and mechanical propulsion systems must be triggered by the starting gate and must not impart motion when the car isn’t racing. Races will not be rerun if propulsion systems fail to activate. Sound making devices, if used, should be designed to remain silent when the car is not in motion.

  • Heats in the No-Rules division shall be conducted the same way as the Pack Championship Series. The 1st, 2nd, and 3rd place finishers shall receive an award.


DESIGN AWARDS

Cars that race in the Pack Championship Series or Open Division shall be eligible to receive Design Awards that recognize exceptional craftsmanship, creativity, and originality. Winners shall be presented with an award.

Award categories for craftsmanship:

  • Best Body Design
    (judged on difficulty and quality of execution, not creativity)

  • Best Paint Job
    (judged on difficulty and quality of execution, not creativity)

  • Best Detailing
    (spoilers, fenders, steering wheel, windshields, etc.)

Award categories for creativity and originality:

  • Best Car Name

  • Cutest Car

  • Funniest Car

  • Fastest-looking Car

  • Scariest Car

  • Most Patriotic Car

  • Most Futuristic Car

  • Best Classic Car

  • Most Colorful Car

  • Most Realistic Vehicle
    (can look like any real-life vehicle such as a bus or tank)

  • Best Theme Car
    (based on a TV, movie, toy, video game, or book)

Design awards shall be judged by a panel of adults consisting of one parent from each den, appointed by the Den Leader. Judging shall be performed after check-in has closed and all cars have passed inspection.

No single car may win more than one Design Award. If a single car earns the highest score from judges in multiple categories, the car shall be declared the winner in the category where it made the strongest showing (by number of votes), leaving the other categories to the next runner-ups. A category can be skipped if the judges determine no car exemplifies the category.

If there is a tie, or any situation where the judges’ scores do not indicate a clear outcome, the Race Committee Chairperson shall make the final determination (which can include recognizing both cars as co-winners if a suitable award is available).