Let me 1st be upfront and tell you the pinewood derby was never intended to be for the kids anyway. Maybe bonding but this is an adult competition. Let’s not deny this. As long as the kid is taking ay interest or a active hand, it’s all good.
Now let’s win this.
Don’t Cheat – Check the Rules – Win
In the past people have cheated by using some sort of mechanism that rolled a ball bearing from the back of the car to the front. The mechanisms were hidden inside the car. The act of the bearing striking the front of the car after the launch gave the car an added boost of speed. The car’s owners were disqualified after someone got suspicious and checked the car. parts including the weights must be fixed to the car. That is they are not allowed to move relative to the car. BB’s and fishing weights are allowed but must be glued or fixed in place.
Put your weight in the back
When you start your car is in the starting block at an angle with the back of the car higher. You want as much as far back because the back of the car is then higher then the rest of the car. That gives you as much potential energy as possible. When the car reaches the level part of the track your weights have fallen farther then if the weights are in the middle or back. Therefore you have more energy when the car reaches the flat section which translates into extra speed. Assuming you have good axles and straight wheels you’re car will be about as fast as possible. Good smooth polished axles combined with rear weighting is the best combo for a fast car. Wind resistance helps but almost negligible for such a short distance and slow speeds.
Also in regards to the weight placement, right in front of the rear axle is considered the best placement. If it is behind the rear axle it makes the front too light and makes the nose want to hop every time the front wheels roll over the track joints. You want the center mass (weights) positioned as high up as possible on a slope because once the car is level the center mass’s momentum can no longer be affected by gravity. Since the rear of the car is the last portion that makes it to the flat track gravity is pulling the center mass down until that point in time.
Good lubrication -Graphite powder on the nails, makes that thing faster than hell.
Wheels must move freely with no binding. Another trick is to not paint the wood where the wheels might touch and rub dry graphite into the wood in those spots. drill and file them smooth to get rid of the burrs, then polish them up.
Note the last rule. “No loose materials of any kind are allowed in the car.”
Learn how to melt lead.
Pour in melted lead to bring the weight close to 5 oz, then epoxy in lead shot to finish up the last 10 grams or so. If overweight, pop out a few balls of shot at a time until your on the mark. And always overshoot by several grams on my scale, so that if their scale is reading low, Take advantage of that.