The most important aspect of selecting a pinewood derby axle for your race car is to keep in mind that the more accurate and straight your axle is, the more likely it is that the axle will work the way you want it to, contributing to your winning races on a regular basis. According to the rules set up by the Boy Scouts of America, which sanctions pinewood derby races, specialty axles are not permitted in pinewood derby races. This means that you'll have to make certain that the axles you receive in your pinewood derby car kit are of sufficient quality so as to provide you with the best performance possible. There also are a few things that you can do to improve the axle's performance, such as filing off the production marks and making sure that the axle is straight and does not wobble.
Begin by removing the pinewood derby wheels and axles from the box before you make your purchase. Inspect the axles for signs of bends or burrs that could contribute to added friction or drag on the wheels. Run your fingers over the point between the axle hub and the tip. It should be uniformly smooth, with no signs of irregularities.
Check the back of the axle hub, and you will see two lines. These are production marks. You can make your car faster by filing off these marks. Making sure that they are relatively small will reduce the amount of work that you will have to put in to make the axles work without a hitch.
Slide a wheel onto each pinewood derby axle and wiggle the wheel gently back and forth. Wobble during races contributes to added drag on the car, which will in turn slow you down. The wheel should be tight, but not snug.
Pinch the pinewood derby axle just behind the wheel to hold it in place, and then use your other hand to give the wheel a spin. If it wobbles too much, it will catch on your finger and slow down quickly. If the wheel and axle are properly fitted, the wheel will continue to spin smoothly without wobbling.
In unrestricted pinewood derby races, your pinewood derby axle can be used to obtain the greatest performance from your car. Specialty axles typically use reduced-friction polished or coated surfaces, include reservoirs to hold graphite lubricant and have set-back heads that reduce the amount of contact between the wheel and the axle. These pinewood derby axles focus on eliminating the wobble associated with pinewood derby wheels and eliminate the friction between the wheel and the axle, both of which significantly slow down the car. Using a specialty pinewood derby axle, however, can result in disqualification from races if you use them during sanctioned Boy Scouts of America races.