OK, so you already know that friction is enemy number one to the Pinewood Derby car builder.  One troublesome point source of friction is where the wheel hub rubs against the car body.  During the race, the wheels tend to migrate back and forth on the axle shaft and make contact with the car body.  Occasionally, a wheel will migrate into the body and stay there creating a braking effect all the way down the track. There are several techniques, some are not legal, to reduce the friction of this rubbing.

Many experts agree that its best if the wheel hubs never touch the body at all.  The only way to accomplish this is to cant both rear axles.  We want to bend both rear axles up so that the wheels migrate toward the inside of the axle head and not the car body.  It is true that this process simply shifts the wheel friction from the car body to the axle head however, the amount of friction is greatly reduced.

You can bend the rear axles using the same methods discussed above in the Rail Riding section using Derby Worx Axle Press and Rail Rider Tool.  Depending on who you talk to, the amount of rear axle canting should be from 1.5 to 2.5 degrees.  The Derby Monkey uses 1.5 to 2.00 degrees canting on its cars.

After applying lubrication to the wheels and axles, install them with the location dot of both rear axles at the 12:00 position… or position your axle head groove in the vertical position.  Look at the car from the rear and make sure that the tops of the wheels are leaning in toward the body.

Gently roll your car on a flat surface and concentrate on the rear wheel hubs. If the hubs migrate toward the body and rub against it, then slight turn the axle with pliers of an axle head screwdriver.  Continue to test and adjust until the wheels migrate out and against the axle head.  Perform this with the car rolling forward and backward.

Try to make sure that each rear wheel is parallel to the car body… at least as close as possible.

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