ONE OF THE MAIN REASONS FOR SPEED LOSS IS DIRTY WHEELS!
Dirty wheels are one of the main reasons a pinewood derby car slows down over time. Often mistaken for alignment issues or lube breakdown, a simple wheel cleaning can restore up to .03! You should always clean your wheels before a pinewood derby race.
Instructions: Using the weight of the car, rest the wheel on the cleaner and spin the wheel with your finger starting on the #4 grit and progress to the #7 grit until you hear the sound of smoothness and feel the wheel surface become smooth again. The coarse grits can be used to clean up and bad gouges to the wheel. PLAY WITH EACH OF THE 4 SMOOTHEST SIDES TO SEE IF YOUR CAR SPEEDS UP!