Pinewood Derby
2024 Pinewood Derby
1. The Pinewood Derby Kit
Derby kits will be available to purchase for $5. The pack will have kits at the November, December, and January pack meetings. Be sure to attend. If you are unable to attend these meetings please contact the pack. Additional kits for siblings, alumni, or outlaw division races (more on this below) are available to purchase for $7.
2. Building your Car
For new parents who have not built a car before, don’t worry. We’ve included a basic video to help explain how to build the car.
https://youtube.com/watch?v=NowS_Kk5szA
You also find right here on this pack website additional building instructions. If you have any questions please reach out to any of the leaders and we can help! The goal behind the derby is to foster an opportunity for parents and scouts to spend some quality time building something together and then have fun seeing it go down the track!
3. Race Details
There will be 4 race divisions this year
1. Traditional Scout Race
2. Siblings
3. Alumni
4. Outlaw
For each division cars will race 4 times, once in each lane. The cars will be electronically timed. The average time of the car’s 4 races determines its placement. We do not use elimination techniques.
See the general rules on this website for an explanation of the rules that the traditional scout race and sibling/alumni will follow.
The Outlaw division has the following rules
1. The car must not compromise the track or impede fellow race cars.
2. The car must operate under its own gravity-fed power. No motors, springs, etc.
3. The outlaw car can be built however you want. There are no weight restrictions.
In addition, all cars entered in the traditional scout race will be eligible for participation in the special car awards. Once all cars are checked in, the Pack will be voting on the top cars in the following categories:
• BSA Representation (Scout Theme)
• Sports Theme
• Best Paint Design
• Most Futuristic
• Most Original
• Most Realistic
• Fastest Looking Car
• Most Patriotic
• Most Unique
• Best Design
4. Car Drop Off
Car drop off is occurring at the New Hope Presbyterian Church on:
Friday 1/26/2024 from 6pm - 8:30pm
Address:
1580 Kisker Rd,
St Peters, MO 63304
Please ensure the cars are as race ready as possible. Again, if you need any help, please just reach out before drop off day and we can help!
5. Race Day
Saturday 1/27/2024
Doors open: 8:30 am
Race starts: 9 am
Address:
1580 Kisker Rd,
St Peters, MO 63304
Class A uniforms
Resources
Pack 936 Pinewood Derby Rules (pdf)
Book – Pinewood Derby Speed Secrets by David Meade (ISBN-10# 0-7566-2733-8)
Book – Pinewood Derby Guidebook (ISBN-10# 0-8395-3721-2)
Past Results
2022 Results - Re-watch the Race: https://youtu.be/2nbjk-P2FLk
2021 Results - Re-watch the Race: https://youtu.be/rvWcbO0PO-A
Pack 936 Pinewood Derby Rules
General Rules
Class A uniforms will be the dress of the day.
The Scout Race is open to all Scouts registered in Cub Scout Pack 936.
With the exception of weights and decorations, only materials from the BSA kit should be used. This is explained in detail in the Wood, Wheels and Axles section, below.
Cars will race 4 times, once in each lane. The cars will be electronically timed. The average time of the car’s 4 races determines its placement. We do not use elimination techniques. Race results (rankings, times, lane statistics, etc.) will be published after the race and posted on the Pack Website. This information is available immediately after the race if there are disputes.
The race will be conducted according to Scout rank. The fastest three cars from each rank will be awarded Rank Trophies.
The 3 fastest cars from each Scout rank will advance to the finals. The top three racers in the finals will be awarded Pack Trophies.
Certificates will be awarded for special car designs. Special emphasis is given to scout-built cars. Expensive kit cars and obviously professional paint jobs are not judged better.
Only race officials and boys racing will be permitted into the registration and track area.
No hazardous materials (such as mercury) are allowed in the race building.
Cars with wet paint, anything dripping from the car, or cars failing to maintain bottom clearance will not be allowed to race. This is to protect the track.
Disrespectful conduct by any participant or member of the audience will be grounds for expulsion from the competition and/or race area.
Inspection and Disputes
Proper car dimensions are required to participate – so there is no damage to the track or other cars. Size dimensions will be checked using the official sizing-box.
The official race scale that is used at car check-in is the final authority regarding car weight. The TRACK is the final authority regarding bottom clearance.
The official race scale, sizing-box and the track will be available before the race to check you car’s dimensions and weight.
There will be no disqualifications from participation unless there is a risk of damage to the track. Correct car weight/dimensions and wheels/axles having no illegal modifications are required to win a speed trophy, but a certificate and/or participation trophy may still be awarded.
Each car must pass inspection by the official Inspection Committee to win a speed trophy. The Inspection Committee has a responsibility to disqualify those cars that do not meet the specifications from winning trophies or to keep them from racing is there is risk to the track.
If the car is damaged, a reasonable amount of time shall be provided to make a repair (a few minutes).
If a car jumps off the track, the heat will be run again. A car will be provided this courtesy only once per heat.
If a car leaves its lane and interferes with another car, the heat will be run again. If the same car leaves it’s lane a second time and interferes with a car, the heat will be run again without the interfering car.
Any participant (including a parent of the participant) may appeal to the Race Committee for an interpretation of the rules. The Race Committee, by majority vote, will be the final judge of the rules.
Sibling, Akela & Alumni Races
After the Cub Scouts are presented with their awards, their Siblings can race for fun. No trophies will be presented, although if circumstances warrant special certificates may be.
After the siblings race, the Akelas and Alumni (which includes past Cub Scouts and Akelas) can race. All rules from the Cub Scout race apply except:
Non-BSA blocks, speed wheels and speed axles are permitted.
Speed wheels must still have Official BSA stamped on them.
Derby Car Specifications
Car Dimensions and Weight
The overall length of the car shall not exceed 7 inches.
The overall width of the car shall not exceed 2 ¾ inches.
The car must have 1 ¾” clearance between the wheels.
The car must have 3/8” clearance underneath the body so it does not rub on the track.
The car weight shall not exceed 5.00 ounces.
Wood, Wheels and Axles
Only use the materials supplied in the kit for the car body, wheels and axles. Decoration exceptions are listed, below.
Official BSA wheels and axles from the car kit must be used. The materials are flawed, so some modifications are permitted:
Wheels may be lightly sanded (to remove the mold projection on the tread), rounded, the inner hub coned, polished and lubricated. The wheel bore may be polished and lubricated. These are the only wheel modification allowed.
The axles may be filed to remove burs and ridges, beveled under the head, polished and lubricated with dry powder (any blend of graphite, MOLY and/or Teflon).
Oil lubricants are not allowed.
Use the pine block provided in the BSA kit.
Axles must be mounted in the slots provided. Do not place wheels/axles in any location other than in pre-cut slots.
Drilling holes for mounting axles or changing the distance between the slots is prohibited.
Any type of decorations, including paint, decals, plastic or metal ornaments are permitted. – But understand that cars that don’t appear scout-built may not receive special awards.
Car Modifications Not Allowed
Wheel bearings, washers and bushings are prohibited.
Removing material from the wheels to reduce wheel weight is not allowed. This includes drilling, thin sanding and/or lathing. Calipers may be used to measure wheel thickness. Wheels that have been thinned will disqualify the scout from winning a speed trophy.
Wheels and Axles may not have grooves or ridges added. Some non-BSA wheels and axles are lathe turned to create grooves or ridges. They are not permitted in our race.
The cars must not ride on any type of springs.
No starting devices. The car must be freewheeling. Nothing may extend past the front of the starting gate or extend above the car onto the top of the starting gate to give an advantage at the start.
The Official BSA wheels, axles and pine block from the car kit must be used. No exceptions:
Vendor-supplied wheels and/or axles will disqualify the car from a speed trophy.
Vendor-supplied car bodies will disqualify the car from a special award certificate.
Tips for Building a Pinewood Derby Car
The basics
The front of the car should be at least 1 inch wide to fit the starting gate.
Wheel alignment, reducing friction and weighting your car correctly impact speed far more than aerodynamics (the shape of the car).
The block starts out weighing about 4 ounces and the wheels and axles weigh about ½ of an ounce combined. Between 2 and 4 ounces of your car’s weight should come from the weights. So, design your car so that at LEAST ½ of the block is cut away. The fastest designs receive the least total weight from the block and the most from the weights. Overall, a simple wedge is a good design.
The center of gravity should be slightly in front of the REAR axle. Design your car so that the weights are placed low and to the rear.
Your design should allow for weight to be added or taken off easily in case your car does not meet the 5 ounce limit.
Tungsten weights are the best – but they are expensive. Lead weights are good, but lead is toxic and must be handled very carefully.
Airbrushing will give the best results, but this takes a considerable investment to do it right. Spray paint is the easiest, but the fumes are unhealthy. Brush paint can be enamel or acrylic. Acrylic paint is water based and much easier to clean-up afterwards – this is the best choice for the scout who paints his own car.
Design your car – plan your car first, build it later – You’ll be glad you did!
Your design should consider how and where you will mount your weights:
Placing the weights to the rear is simple. Hobby shops have metal plates that can be screwed onto the car. Don’t put them on the bottom unless the required 3/8 inch clearance can be maintained.
Getting them low is more difficult – the easiest method is to drill holes in the side above the rear axles and insert metal wire.
If you have a router, you can cut a pocket in the bottom of the car for the weights. Be sure to consider how the axles will be mounted securely.
Draw your car to scale on paper or draw directly on the car block.
Buy your materials (you should be able get everything you need at a single hobby shop or online vendor)
We recommend that you buy a car kit from the Pack. You may want to buy a second kit in case you make a serious mistake on the first one. If you don’t – you already have next year’s car.
Local hobby stores and online vendors offer car kits and weights. You will need at least 2-4 ounces of metal weights to build a fast car. Please don’t use non-BSA wheels and/or axles. If your wheels and axles are not official BSA, you will not be allowed to race in the finals or win a speed trophy.
Decide what type of paint and brushes you will use. Again, brushed-on acrylic paint is good. You can buy this much cheaper at a craft shop than a hobby shop. The sponge-type bushes don’t work well at all. If you care about how your car looks, spend a few dollars on some good, natural bristle brushes. They will last for years if you clean them properly.
Choose some really cool decals or a “skin” for you car.
Lubricant – get a tube of graphite. No oils, please – they can ruin the track.
Start Building!
Drill holes or use a router to make a pocket for your weights.
Cut your block. A band saw works best, but a coping saw, hack saw, or even a hand saw will get the job done.
Now, weigh your block, wheels and axles, and your weights together. Your materials should weigh between 4.8 and 4.9 ounces. Painting and final adjustments will account for the rest.
Sand, prime and paint your car
If your block is rough, start with 60-grit sandpaper. If your cuts were smooth, you can start with 100-grit or even 200-grit. Work your way up to 400-grit for the final sanding before you apply primer. Wipe well to remove any loose material.
Cover the axle holes or around where the slots show on the side of the car with a piece of painter’s tape, masking tape or electrical tape. The area covered should be slightly bigger and in the same location as where the wheel will meet the car.
Just about any primer will do. It’s better to use enamel primer with enamel paint, though. Follow the instructions on the can and let it dry thoroughly. Then sand your car again. If your strokes were smooth, you can start-out with 400-grit. Otherwise, start with 200-grit and then finish with 400-grit. Your car should be VERY smooth at this point. Wipe it down well to remove any loose material.
Painting takes a LOT of patience!
If you are patient, you will get it right. If you aren’t patient it will actually take much longer to get it right. No matter how well you plan, design and build your car, it won’t look great if you get impatient between coats of paint. If you don’t care – you’ve got it made – because paint doesn’t make a car go faster, anyway.
Apply the first coat of paint. You might be satisfied with the results of a single coat, but that’s unlikely. Plan on 2-3 coats of paint (or more).
The first coat should be thin – so thin it doesn’t even look very good, yet. Just get a good coverage and let it dry thoroughly. Acrylic paint may take 30 minutes to a couple of hours to dry. Spray paints can take longer. It won’t hurt to wait until the next day to be sure it’s dry.
After it’s dry, sand it again using 200 or 400-grit sandpaper. Wipe away the loose material and start your second coat. The second coat can be a little thicker, but not so thick that the paint starts to run. This is the hard part – deciding how thick your final coat should be. If your paint runs and you can’t get the runs out without ruining your paint job, just wait a day or two and sand it smooth. Then try again.
You can add coats and sand with ever-finer grit sandpaper (600+) until you achieve the desired result.
After you are finished painting, you may want to add decals. The dry transfer type work very well. Just read the directions and be careful.
Decide if you want to add a final gloss coat. Spray lacquers can add a glass-like sheen that looks great. If you used acrylic paint or added decals, be very careful with the final gloss coat. If you don’t let your paint cure or apply the first coat too thickly, it will ruin your paint job. The first coat should be almost a mist. Let this dry and apply a second mist-coat. The final coat can be thicker, but not so much it runs. If it does, let it dry thoroughly and sand it smooth. Then try again.
Remember – patience!
While your paint is drying, you should start working on your wheels and axles
Axle Preparation:
Only use stock BSA axles. Changing the shape of the axle (also known as Speed Axles) or axle head is against the rules, but you might want to be sure it’s straight. If it wobbles when you turn it in the drill, you should choose another axle or use an Axle Press.
Stock BSA axles have a bur under the nail head that needs to be filed smooth. Put the axle in a drill and use a small file (a nail file will work) to remove the bur.
Polish your axles with fine grit sandpaper (600+). Clean them thoroughly with water or rubbing alcohol.
Wheel Preparation:
Only use stock BSA wheels. The stock BSA wheels will have a mold mark that needs to be sanded smooth. The best way to do this is to attach the wheel to a drill with a mandrel and gently rub the wheel on moist, 600-grit wet/dry sandpaper that has been attached to a sanding block. If you turn it too quickly or the sandpaper becomes dry, it might actually melt or deform the plastic, so be careful.
Smooth the wheel bore hole using a fine abrasive (whitening toothpaste works, too!) applied to a pipe cleaner. Clean thoroughly with water or rubbing alcohol.
Lubricate your wheels and axles:
Use graphite or Teflon powder to lubricate the wheels and axles. Graphite works better, but it is messy. NO OILS are allowed.
The wheels should spin on the axles for about 20 seconds.
Mount your wheels and axles
This is what you have been waiting for! If you begin too soon, you will ruin your paint job or at least leave a lot of fingerprints in the paint. So you may want to wait at least 1 or 2 days after your final coat of paint to begin this step.
After your paint has thoroughly dried, remove the tape that covers where the axle meets the car body. You can either use a dull graphite pencil or just rub some graphite onto this spot. This will provide lubrication between the car body and the wheels.
Put the axles into the wheel holes and gently press into the car body. You should leave a gap of 1/32 inches between the wheel and the car body. You can use the Spacing Tool or just cut a notch in a couple of business cards stacked together to maintain this gap as you insert your axles. A few taps from a small hammer may be necessary to get them completely in the car body.
After all 4 wheels and axles are mounted place the car on a flat surface. All 4 wheels should touch the ground and they should be straight horizontally and vertically. You may have to remove an axle with pliers if they aren’t straight. Be very careful you don’t damage the car body, axle or wheel. This can be the most frustrating task – and the most disastrous!
To test your alignment, the car should roll straight on a clean, flat surface for at least 10 feet before pulling slightly to one side or the other. If the car is not aligned properly, you might choose to realign it by SLIGHTLY bending the axles.
The final task is to drop some glue on the axles on the bottom of the car to secure the axles. Leave the car turned upside down overnight to ensure the glue dries without dripping out.
Final Check-up (the night before the race)
Weigh your car using the official scale. If it doesn’t weigh enough, add weight as necessary. If it weighs too much, use a drill to remove material. Less holes are required if you drill into the weights.