It’s that time of year again. Time to bust out the tools for some Pinewood Derby fun.
But first, how did you do do last year?
Was your car fast? Or just meh?
Let’s change that…
So, you want to build fast pinewood derby car? You want to win?
The good news is that making a fast car is easy and doesn’t have to be expensive.
Now, I can’t promise that you will win, but you can learn 5 steps that will dramatically increase your odds of building a winning car and you will also learn why.
Let’s get started…
But first, if you don’t have a drill press or other specialty tools, check out the links below for cheaper alternatives so you can still benefit from these techniques.
Our two main goals are to create a good center of gravity and to reduce friction.
Step One is finding good axles and preparing them for speed
These two nails may look the same, but they are not. One is straight and the other is slightly bent. The one is a winner, the other will cause the car to drift and bang into the track. This slows this car down.
The easiest way to find straight axles is to put it in a drill and look for ones with the least amount of wobble.
Next we want to use a metal file to remove crimp marks on each nail to reduce friction.
Go light here. Stop as soon as the crimp marks are gone. We don’t want to remove too much metal.
Finally, we want to polish each axle. We will start with a fine grit sand paper and work our way to a really fine grit paper. Only spend twenty to thirty seconds on each grit. We want to polish, not remove metal.
Step Two is finding good wheels
The wheels are made in several different molds. Some are good others are bad.
Take each wheel and spin it on one of your polished axles. Keep the wheels that spin the longest with the least amount of wobble.
Step Three is drill axle holes for optimal speed
If your rules allow, don’t use the grooves for your axle placement. The grooves may not be cut evenly which can lead to drifting and the axles can easily get knocked out of alignment.
Instead, we want to move the wheels as far as possible to the front and back of the car without exceeding the allowable length of the car. This extended wheelbase will help the car track straighter down the track.
For the rear wheels, we will drill the axle holes at a 2 degree angle called canting. This will cause the wheels to move up away from the wood and ride on the edge of the wheel reducing friction.
The front right wheel will be drilled flat, unless you want to try rail-riding which I won’t be covering as it can be finicky to get right.
The front left wheel will be drilled 1/16 inch higher than the right wheel. This wheel is lifte just enough to not actually roll on the track. Your car will be riding on three wheels to reduce friction.
Don’t drill this too high, because if the car drifts a really high wheel can cause the car to jump over the center rail and crash.
Step Four is to place your weights properly
We want to move the weights to the back of the car. This will position most of the weight higher on the track. This leads to higher potential energy and a faster car.
But the weight must not be so far back that the front of the car loses control.
The weights should be placed so that the center of gravity is about an inch in front of the rear axles.
Step Five is to use graphite the right way
Putting too much graphite on your axles, or putting more on after each run will actually slow your car.
You want apply some graphite. Run the car down the track once or twice to break it in or spin the wheels by hand if you can’t run the car before the race. The next five to six runs should be actual race runs without adding extra graphite.
Alright. Time for some bonus tips.
Bonus tip one. If you are on a budget, you can save money buy using fishing weights instead of expensive tungsten weights. We have won with both types.
Bonus tip two. If you don’t have a bandsaw or belt sander create that thin car body, you can buy an official pre cut wedge body for a couple of dollars. Link below.
Bonus tip three. Don’t use the weights that are screwed or glued to the bottom of the car. On some tracks, these will rub on the rail under the car and greatly slow the car down.
That’s it. Go out and have some fun. Remember to let the boys help and teach them the science behind making a fast car. A winning car is really a loser car if the boy doesn’t help build it.
What do you do to make fast pinewood derby cars? Share your comment below.