Derby Car Design Tips
Designing and Building Your Car
You don’t have to strive for the fastest Pinewood Derby car to have fun competing in your Pinewood Derby. But if you and a helpful adult are willing to put in the extra time and effort, these tips are for you.
- Bake the Block: Start with your block of wood, and before you do anything else, bake it in the oven at 250 degrees for around two hours to remove moisture and make it lighter. This will allow you to place more weight to the rear of the Pinewood Derby car where you actually want it.
Create the Design: Draw the outline of your Pinewood Derby car on a sheet of paper, cut it out and attach it to your block of wood. Remember, a rectangular car is not an aerodynamic design. The most basic aerodynamic design is a simple wedge. If you don’t have time to design a complex car, a wedge will work just fine. Click here to download a pinewood Derby car template PDF to help you create the design
Rough Cut the Design: Use a coping saw to cut out the rough shape of your Pinewood Derby car. You can also ask a responsible adult to make these cuts using a power tool.
Shape Your Car: Use sand paper to smooth your car’s edges and shape it to your design. An adult can also use a rotary tool or other tool to help you.
Sand and Paint the Pinewood Derby Car: Make it smooth to reduce friction and paint an awesome design to make it look great. Click here for tips on painting your Pinewood Derby Car to give it a shiny finish
Install Axles and Wheels: Make sure they are aligned perfectly straight. You can test the alignment of your axles by pushing your car across a smooth floor or table. It should roll smoothly in a straight line. Click here to learn about polishing Pinewood Derby axles and wheels to reduce friction.
Make a Three-Wheeler: Raise one wheel about 1/16 inch higher so it never actually touches the track. Less friction = more speed. Rules vary from pack to pack, so make sure to check your pack’s Pinewood Derby rules to make sure three wheeler cars are allowed in your race
Extend the Wheelbase: The front and rear wheels should be as far apart as possible. Again, make sure this is allowed in your race.
- Create Glue Holes: Glue the axles firmly in their holes to ensure that they stay perfectly placed, but make sure you don’t get glue on your wheels.
- Add Weight: Remember to make your Pinewood Derby car as heavy as the rules allow. In general, it’s best to place weight to the rear of your car because a heavier rear increases speed. Click here for scientific Pinewood Derby speed tips from a former NASA engineer
- Lubricate the Wheel Well: Add graphite or another dry lubricant to reduce friction. The less friction between the body and wheel, the better.
And finally, remember the No.1 rule of a Pinewood Derby is that it’s supposed to be fun. While you should always strive to do your best, don’t get caught up in winning or having the fastest car.Just enjoy the ride.Going Straight
- Put the axle in at a downward (5-10 degrees) angle. This provides two benefits. The first is the only the inside edge of the wheel is in contact with the track. This seems to make the car go straighter with less wobble. The second benefit is that the wheel rides to the outside of the axle and doesn't come in contact with the body. This tip is for experts only. First timers have trouble getting this right.
- Axles must be in straight front to back. That is square to the body. True the axles, don't trust the slots! If you have one, use a drill press to ensure all axles are straight. One of the front and two of the back should be measured to be the same height.
- After pressing in the axles, test the car for crooked wheels...roll it on the floor. If the wheels are on straight, the car should roll 8-10 feet in a fairly straight line. Should the car turn left or right, you need to tinker with the axle placement without removing them from the car body, until it rolls straight.
- Do not put the axles in at the top of the groove. Put them in at the middle. This lifts the car off the track a bit more and reduces the chance of rubbing on the center strip.
- Glue the axles in place. Nothing is worse than having the wheel fall off as you cross the finish line.
- Once you match a wheel and axle together with graphite, keep them together. They wear into each other as a matched set.
More Design Tips
The possibilities are endless when it comes to picking a shape for your Pinewood Derby car. Before you begin, consider the following general guidelines:
- Measure Twice, cut once! Have your child draw a design on paper then cut it out and use it as a template. I use the paper with the little squares on it to make it easier for him. Draw a side and top view on the paper by tracing around the block of wood.
- Keep the car a full seven inches. It has to do with the physics of velocity and length of travel of the weights.
- Use the full 2 3/4 inches (outside wheel to outside wheel) that the rules give you. This will allow the wheels to travel farther before hitting the center strip.
- Avoid designs with a pointed nose. A pointed nose will make it difficult for your Pinewood Derby car to rest on the pin at the starting gate. It may also cause your Pinewood Derby car to get bumped around when the pin drops, and it can create problems for electronic timing systems.
- Leave enough wood in the rear of the Pinewood Derby car so you can place additional weight there. You will end up placing most of the weight in the rear of the Pinewood Derby car.
- Make the maximum weight. Your car should weigh as much as it’s allowed. In most races, a Pinewood Derby car’s weight is limited to 5 ounces. If your car weighs less than that, add coins or other weights.
- Be sure that it is very clear which end of your Pinewood Derby car is the front and which end is the back. In many races, the race officials (not you) will actually place each Pinewood Derby car on the track. Sometimes the officials put the Pinewood Derby car on the track backward because they can’t tell which end is which.
- Use your imagination. Be creative. Shape has the least to do with winning. A beaver driving a log or even a pickup truck is more interesting than a wedge and will be just as fast.
- Choose a design that allows the air to move over and around the Pinewood Derby car body in a smooth manner. Pinewood Derby cars with aerodynamic profiles go faster.
Lubrication
- Use graphite only. Oil damages the paint and collects dust. I'm told that the graphite works better than the new white Teflon.
- Break in the wheels by spinning them with lots of graphite.
- Right before check-in, fill the wheels wells with graphite and cover with stickers like a hub cap. You can paint the 1 inch stickers in a contrasting color. It looks great! Remember, after the car is checked in at registration, no further modification is allowed; including lubrication!
- Put a small drop of white glue where the axle goes into the car body and put powdered graphite on it there. That causes less friction if the wheel should rub against the car body.
- Other than the good polishing of the axles, dump the axles and wheels in a Ziploc bag with some graphite and shake them for a few days prior to the race. That way the wheel and the axles are as slick as can be.
Weigh-In
- Get the weight as close to the 5 ounce limit as possible. Add the last little bit of weight with lead tape. This can be trimmed with scissors at the last minute. Remember, the official scale may not weigh the same as yours.
- Everyone has an opinion on where to put the weight. It is a well-known shared opinion that the weight needs to be predominantly in the rear, so that gravity can act upon the weight further up the incline and for a longer period of time. A car with more weight to the rear generally grabs more speed down the slope. Many suggest having the center of gravity at 1 inch, to one and a half inches in front of the rear wheels. Be careful not to put too much in the rear or you'll pop a wheelie.
- What kind of weight? These days, melted lead is dangerous and unnecessary. Tubular weights can be sunk in the sides; flat weights, like those sold at hobby & council stores can be attached to the car bottom if it is carved in a bit. Incremental weights ( with grooves) are easier to snap off into the size you need. Some folks just use BB's, nuts & bolts, etc., but these must be glued so that they can not move. No movable weights or mercury are allowed.
- Round weights found at the hobby shops and craft stores work great. This allows us to stick the weights out the back of the car. You can paint them and tell everyone that they are jet engines or tail pipes. What they really do is allow you to get the weights as far back as possible.
- Keep the weight low on the car and in the center (Left/Right of the car). Put the weight just in front or behind the rear wheels for less wheel chatter.
BSA Cub Scout Pack 615. Est. 1987