Should you graphite the wheel tread on a pinewood derby car?

Dry lubricant is the only allowable lube by standard BSA rules. Graphite is a dry lube and it will not dry out. Do not mix dry and wet lubricants. They will not work well together.

Although graphite does not dry out over time, it can in fact draw moisture from the air it is exposed to over time. This all depends on the humidity levels of the air that the car/graphite is being stored in. If the graphite draws moisture it will start to act like a paste and slow the car down by placing more friction on the axles. I always recommend re-graphiting your wheel just before any race.