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. The aerodynamics of a small block of wood doesn't mean much in thirty feet.
Use the groove closest to the end of the block of wood as the rear axle.
Note: The Race Starter will place the car on the track according to axle location. The back axel is nearest to the end of the car. The front axel is furthest away from the end of the car. This determines the direction the car will race unless the contestant clearly marks "Front" on the car.
Do not make the front of the car pointed. It is hard to set up against the starting dowels. You can taper the front end but please leave at least the center 1/2" to set the car on the starting line.
Leave a lot of wood in the back to put in 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.
Keep the car a full 7" in length. It has to do with the physics of velocity and length of travel of the weights.
Once you match a wheel and axle together with graphite, keep them together. They wear into each other as a matched set.
After pressing in the axles into the wood base, 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 the middle of the inside the of groove. 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.
You MUST use the block of wood provided. Purchasing pre-made bodies is NOT ALLOWED.
Wheels may be lightly sanded to smooth out molding imperfections on the tread area. This light sanding is the only modification allowed. Beveling, tapering, thin sanding, wafering or lathe turning of the wheels is prohibited.
Axles may not be altered in any way except for polishing.
Wheel bearings, washers, bushings, and hub caps are prohibited.
The car shall not ride on any type of springs.
The car must be free-wheeling, with no starting device or other type of propulsion.
Axles and wheels shall be only as provided in the Official Grand Prix Pinewood Derby Kit.
Keep the weight low on the car and in the center of the left/right of the car. Put the weight just in front or behind the rear wheels for less wheel chatter.
If you use the round weights found at the hobby shops and craft stores, it allows you to stick the weights at 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 us to get the weights as far back as possible.
What kind of weight? The 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 pre-marked 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.
Everyone has an opinion on where to put the weight. 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 to 1-1/2 inches in front of the rear wheels. But be careful not to put too much in the rear or you'll pop a wheelie.
Get the weight as close to the 5 ounce limit as possible. Add the last little bit of weight with lead tape from the golf shop. This can be trimmed with scissors at the last minute. Remember, the official scale may not weigh the same as yours.
The wheel-base (distance between the front and rear axles) may not be changed from the kit body distance of 4-1/4 inches.
The minimum width between the wheels shall be 1-3/4 inches so the car will clear the center guide strip on the track.
The minimum clearance between the bottom of the car and the track surface shall be 3/8 inch so the car will clear the center guide strip on the track.
The maximum overall length shall not exceed 7 inches.
The maximum overall width (including wheels and axles) shall not exceed 2-3/4 inches.
The maximum height should not exceed 6 inches.
Use graphite or white Teflon lubricants only. Oil damages the paint and collects dust.
Break in the wheels by spinning them with lots of graphite.
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 ziplock 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.