The Pinewood Derby has been drawing Cub Scouts together for a day of competition since 1953. The noble goal of the derby is to foster a stronger relationship between the Cub Scout and his parent by working together to create a personalized, custom, one-of-a-kind car from a basic BSA kit. It is hoped that a scout feels pride in his work, enjoys the competition of racing against other scouts, and demonstrates good sportsmanship whether he wins or not.
Pinewood Truths
I've been through 6 years of Pinewood Derbies with my sons. The first year was a rude awakening to the reality of Pinewood Derbies. These are the few truths I discovered:
- Some dads do all the building of the car and the scout carries the trophy home. There is no way to prevent this.
- Some cars are purchased ready to race rather than built. There is no way to prevent this.
- Some fathers will teach their sons that cheating is ok.
- Most scouts prefer to roll their cars around on the gym floor after the race rather than care about who won.
After the first derby, I sat down with my sons and we talked about the various levels of craftmanship and speed we had seen. They decided that next year they would try to win the Most Creative award instead of the Fastest Car because the scouts all voted on the Most Creative. They recognized that some scouts did very little work on their car because the scouts told them. They also didn't care about not being fastest. They were already talking about cool designs for next year and asking me if I would do the sawing again - that's all I ever did on their cars. Every year, I also made my own car on which I could demonstrate my creative abilities.
I believe the Pinewood Derby is a wonderful opportunity for a son and parent to have a great time working with wood, learning about friction and gravity, being creative, and just having an excellent time together. As long as the parent emphasizes that they are participating together and does not take over the project, the derby is great. I think the team needs to set a few goals and guidelines before the derby car kit is even opened:
- Enjoy the process and the event, win or lose
- Do our best within the rules
- Hope for the best
- Congratulate the rest
While my scouts were not too concerned about speed, I was very interested. Some of those cars just flew down the track and I wanted to know how. After hours of research, I learned all the tricks for a fast car and I learned the Pinewood Derby is Big Business with a myriad selection of tools, templates, plans, and designs for a dad to purchase in an effort to help his scout bring home a trophy. I decided to try some of the free speed tricks myself - I won the pack's adult competition. The following tips tell you the most important pinewood derby car design concepts. Doing just the first few will make a huge impact on your performance.
Pinewood Derby Car Design Tips
These tips are in order of the most important first. If you have wheels as smooth as glass on axles that are misaligned, it will do no good.
- Heavier is Faster - Pinewood derby cars are gravity driven. Make your car as close to the 5 ounce weight limit as possible. When the car reaches the flat end part of the track, its extra weight means more momentum to continue moving fast.
- Axle Alignment - Absolutely straight, perpendicular axles mean a straight-running car with no drift. Every time your car drifts to the side and touches the lane boundaries, it slows down. The predrilled axle holes may not be true and straight.
- Graphite Lubricant - dry graphite where the wheels and axles meet reduces friction and results in longer, faster runs.
- Longer is Faster - if your rules allow you to move the axle locations, move the front and back axles as far apart as possible. The longer wheelbase results in less car wobble.
- Weight in Back - by moving weight towards the rear of the car, it moves further up the track at the starting point. That means it falls further and propels the car longer. If the weight is too far back, the front of the car will wobble so finding the best location takes trials.
- Polish Axles - the standard axles have imperfections that will increase friction with the wheels. Grinding the ridges off and polishing reduces friction.
- Smooth Wheels - The standard wheels have ridges and bumps. Sand and smooth them to reduce friction.
These are all modifications scouts with adult help can make on their standard kit. There are also many different tools available to help with the more advanced tasks such as polishing axles. And, it's even possible to just purchase pre-polished axles and wheels.
Design Modifications
In a bid to make superfast cars, some folks have modified the design in ways that are often outside the rulebook. These modifications also tend to be outside the skill level of a cub scout. I don't recommend doing these unless you have an unlimited category for adults.
- Thin Wheels - shave down the wheel width so they look like bicycle tires. This causes a very thin track contact point for less friction. It also has less mass in the wheels meaning less inertia and less energy to get the wheels spinning at the start.
- Wheel Grinding - the cap on the axle touches the plastic wheel across its surface. This means for friction to slow down the wheel. Grind away the outter side of the wheel so a thin circle around the axle hole is higher than the surrounding wheel. This causes the wheel to touch the axle cap close to the center where there is less energy wasted.
- Hub Caps - similar to the Wheel Grinding, but better. Make a round paper hub cap to glue onto the wheel after final assembly of the wheels and axles. When the wheel moves towards the car body, the hub cap contacts with the axle cap before the wheel can touch the car body. The spinning wheel and hub cap just touch in the very center of the axle cap resulting in minimal friction. Even better if you put a bit of graphite in the hubcap before final glue-down.
- Raised Wheels - position the axles and balance the car so that one of the front wheels does not touch the track. Three wheels mean less friction. Just make sure the car runs straight on the three wheels. I've also heard of cars being balanced on opposite front and rear wheels with the other front and rear wheels only occasionally touching the track in an effort to further reduce friction.
- Suspension - It is possible to cut your pinewood block in a long zig-zag manner so that the entire piece of wood acts as a suspension. This absorbs more bumps and keeps the mass moving evenly down the track, resulting in less lost energy.
- Track Bumpers - Running down the track, a car will eventually touch the raised center of its lane. This raised center keeps the car in the lane but most cars will touch it with their rotating wheels which slows down the wheels. At the front and rear of the car, add four small brad nails under the car body way out by the sides. These will touch the center rail before the wheels, reducing the friction to the wheel rotation. Another enhancement is to place a smooth bead on the brad nail so it touches the center rail and spins easily, reducing friction a bit more.
For many Pinewood Resources, check out my Pinewood Links page.
Comments:
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Jan 11, 2013 - 2Girls4Speed
Thanks I love the tips. I have two girls, and this year the church is allowing the girls to build cars too. They are definitely interested in the look of the car way more than its speed. As a dad, I do hope a girl beats all those boys though. Â:)
Jan 12, 2013 - Scouter Paul
2Girls - I hope the girls race in a 'siblings' category rather than against the Cub Scouts. ÂThat would be the appropriate way to allow them to race. ÂSome Packs also have a 'Parents' or 'Unlimited' category for those that really want to race, but still keep it fun for the Scouts to race against each other.
Feb 06, 2013 - Michael
Our pack gives every cubscout 2 kits, 1 for them and 1 for their adult partner. We also have classes on a couple of Saturdays to help get evrybody up to speed. I'm proud of our boys and their cars. We have some very close races.
Feb 06, 2013 - Scouter Paul
Michael - That sounds like a great way to encourage an 'adult' car and race separate from the Cubs race. ÂThere are soooo many accessories, tools, and gadgets available at the Scout Shop for Pinewood racers, a class is probably very helpful.
Feb 07, 2013 - Twila
lowes and dremmel tools also hold pinewood derby work shopsin January and Febuary.they have a lot of good tips and show the kids how to use tools to more work on their on.
Jan 02, 2014 - Brice
So where is the line drawn between it being a boys car that a dad helped with and a car that a dad made? My boy made the design, drew it on, suggested modifications and painted it. ÂI have done all the cutting and detail. I know it can't be avoided but if we won I am sure others would think my boy had not made it. Fair enough. Just would like to know what others view as acceptable. Cheers
Jan 02, 2014 - Scouter Paul
@Brice - There is no line. ÂIt's a very wide smudge, interpreted differently by everyone. ÂMy view is that an adult should do the work that could be dangerous to the scout, such as bandsaw, power sander, and the like.The scout can do everything else. ÂGetting the axles in straight is one area where an adult's help would make a big difference.
Feb 01, 2014 - Brian
@ Brice, a 7-10 year old boy will not have the know how to build a car. The most important part is to spend time together, teach techniques in building the car, and let them do everything they are capable of doing. All boys are different and require different amount of help.
Feb 14, 2014 - Robert Wells
As a grandfather new to this grand prix, I would like to see a picture of a typical car. Also not everyone has a  scale accurate enough to measure 5 ounces. Is there a convenient equivalent in so many nickels, dimes or whatever?RW
Feb 14, 2014 - Robert
@Robert Wells, Âmost post offices will weigh your car with their scales free of charge. ÂJust don't try to do it during their busy time. ÂAlso be prepared to make minor adjustments at the derby weigh in if there is a small difference in scale accuracy.
Mar 01, 2014 - Paul
Im building my first derby car with my son and trying to remember all my Dad's tricks, he helped my brothers and me build two 1st place cars and one 2nd place car. The most important thing though is involving my son and teaching him sportsmanship and fairness. I remember sanding my cars, polishing wheels and axles and helping with painting. Axles were totally Dad's domain since they were so critical to the cars running well. ÂOne tip I will share, he would incorporate a small box in the design and buy 1/2, 1/4 and 1/8 oz crimp on type fishing weights. ÂThis allowed quick adjustments if the judges scales read differently from our scales...we could quickly and easily add or remove weight and keep the car at 5 oz. ÂHave fun with your sons and daughters and teach em good scout values!!!
Mar 02, 2014 - Angry Dad
My son loves the derby and doesn't even try to build a car to win. ÂHe just loves cutting and painting the car. ÂThis year it is part painted and part drawn. ÂPersonally it's a little embarrassing BUT he is proud of his unique creation and that is what the derby is all about (in my opinion). ÂHave races for the parents if they want a "professional" looking car but let the boys just have fun with it.
Mar 04, 2014 - Becky
In our rules it says not to use washers and stuff, as weights, and then to read online to use quarters to help weight the cars. Aren't they about the same. What do you suggest to use as weights, that would Âbe laying around the house? And do you think front or back to place weights for speed?
Mar 04, 2014 - Scouter Paul
@Becky - Fishing "pencil weights" are small, easy to cut, and cheap. ÂOr, the BSA has tons of Pinewood accessories available, including official sets of weights. ÂSee all of it at: ScoutStuff.orgIf you read the content above, you'll see information about weight placement. ÂBack is better for speed, but may affect holding the line down the track.
Mar 04, 2014 - Tim
as to weight placement, if you run om a long track place your weights toward the back, 1/3rd past the back axle 2/3 in front of the axle.I drill in from the bottom and put them as high up as possible or use the dome weight from the store. If you have a short track move the weight forward toward the center. weight in back pushes the car at bottom ,weight in center goes faster down slop. We race on 2 tracks one long one short and I move weights for each race.
Jan 13, 2015 - David
Our pack has an "akela" category. ÂThe idea is to prevent parents from taking over the cubs' cars. We also allow siblings - they race with the dens of their age. I make a very intricate car every year - slow but fun. For good or bad, my kids follow that example, and design beyond their own ability, but each year they can handle more and more of their own build.
Apr 27, 2015 - Joe
Be sure of the rules for YOUR Pack to avoid disappointment on race day. Rules can vary from Pack to Pack so be sure to check and to have a printed copy of those rules.
Mar 06, 2016 - Chad B
We are having our first derby this year. Our Den leader gave us the kit and said the den rules are we can only use what's in the box so weights are out of the equation.
We were thinking of just rounding the front/back of the block to save weight and keep it aerodynamic. Would trying to keep most weight to the rear (potential energy) by having the axles closer to the front make sense?
Mar 07, 2016 - Scouter Paul
@Chad - That is a silly rule that your den leader has added. ÂThe scouts can't even paint their cars? ÂIs everyone in your Pack and your District following the same rules? ÂIf not, then whoever wins your den race stands no chance at all in future races.
Moving the axles wouldn't make much difference, probably cause more steering problems. ÂAerodynamics of a block of wood versus a slightly rounded block of wood is miniscule. ÂTrying to keep as much weight on as possible would help. Â
But, really, it's a dumb rule to add to the process because everyone else uses the 5 ounce rule. ÂSome wood blocks will weigh less than others, so your den's rule is unfair.
May 04, 2017 - Asst Cub-master
Our Pack has categories For all dens, Parents, and sibling. ÂI make a decent looking trophy out of scrap wood, and everyone gets one. ÂThere is an over-all Pack winner that can elect to go to District Finals. ÂThere are many publications available at the scout store, and in my opinion "Winning within the Rules" is the best. ÂOur Pack has a design night, a build/weigh in night, and an Inspection Night. ÂAs our District continues to "Change the rules" we ensure that each car would qualify for the District race should it win. ÂWe have fathers that bring power tools to Build/Weigh In night as we have several boys without fathers. ÂWithout these nights, many of our boys would have nothing to race. ÂNext to camping out of doors, it seems that Pinewood Derby is the High Point of the Year. ÂA good time is had by all... our boys learn a lot about their cars... and also learn about sportsmanship. Â NOTE: ÂMy grandson won two years ago by painting his block of wood purple, writing "Barnie" on the car. ÂProperly weighted, it was the fastest thing on the track.... who needs a band saw??
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