Updated: Sep 8
The internet contains a vast amount of information about Pinewood Derby®. Unfortunately, there is a lot of good information mixed with questionable. Let’s look at a few recommendations that, for whatever reason, have gained traction on the internet but don’t necessarily lead to faster cars. Some of the questionable Pinewood Derby® information includes:
Tuning the car or “breaking in” the graphite on a treadmill - Simply put, don’t do it! The belt can damage the relatively fragile wheels, resulting in a loss of speed. To break in the graphite, spin the wheels by hand or run the car down a track. Five minutes of tuning on a treadmill is equal to over 100 races. The wheels will wear out and slow your car.
Packing the wheel hubs with a slurry of graphite and isopropyl alcohol. - Once the alcohol evaporates, you’re left with dry graphite that will spill out onto your tuning board when adjusting your steer or the track during the car’s first heat.
Quick start bar (also referred to as a "Cheater Bar") - In theory, these make sense. It gets the car rolling before the other cars due to the higher contact point with the starting peg. However, with today’s spring-loaded starting gates, the peg slams down much faster than the car can start rolling, negating the quick start bar’s advantage. Further, the bar needs an attachment (often electrical tape) to ensure the car triggers the timer correctly. If not perfectly aligned, the attachment will increase drag, and there is no guarantee it will trigger the light sensor at the finish line instead of the actual car body an inch behind it. Additionally, the “dog bone” design usually associated with the quick start bar is not the best aerodynamically.
Bending the car’s rear axles - The thought process behind bending the rear axles is so the wheels will migrate outward on the axle and ride against the head, reducing friction and stabilizing the wheel. While this is sound logic (and is why league racers drill the rear axle holes at an angle), it is challenging to get them right when bending. Maximizing the car’s speed with bent rear axles will be difficult without a track to tune the car on and a lot of patience.
Polishing/burnishing the entire wheel with graphite - If you use graphite as your lubricant, you should polish/burnish the wheel hubs and bore with graphite. However, you should not polish the wheel treads (the part that touches the track) themselves. While the shiny, gunmetal gray effect looks cool, graphite on the wheel treads will make them too slippery and lead to an unstable, wiggly car. Ultimately you want the wheel treads to be smooth, not slippery!
Baking the wood block to remove moisture - Baking the wood block takes time and effort that is better spent elsewhere. After baking, the block will start to absorb moisture again, likely resulting in a warped body, especially if going with a thin league-style car. A warped body will throw off the alignment and slow the car. The risk of warping outweighs the minuscule weight savings.
The myth that Aerodynamics doesn’t matter - Most of the speed in a PWD car results from properly preparing the wheels, axles, and weight distribution. However, aerodynamics does have an impact and has been thoroughly tested. This fact is proven in practically every professional league race. In classes where aerodynamic additions (thin body, fenders, air shields, etc.) are allowed, any car that runs without these features will almost always finish dead last! In competitive Scout/Youth races, aerodynamics will make a difference.
Many racers claim to have built fast cars using some of these techniques. The truth of the matter is they made a fast car despite using these techniques, not because of them. The majority of the speed is in the Wheels, Axles and Weighting. Focus your attentions there and you will have success!
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