Wheel Selection for Winning Pinewood Derby Cars

Wheel Selection

If your "wheel rules" say that you have to use the four wheels that came in your kit, you can skip this paragraph entirely. Most Packs and Districts say only that you must use official Cub Scout wheels. Well, there are at least three different molds out there. The kits in our District last year came with "new" wheels. These are slightly wider than the "old" wheels and some had raised lettering on the sidewalls. They also had a significantly larger hub area and are about 10% heavier, as is evident in the two photos below. However, the "old" wheels were still available in "wheel kits", which are a box with five wheels and four extra axles. The "old" wheels are lighter and have a much taller sidewall area, which some of the later, more-intensive techniques use to advantage. However, the key is weight in the wheels. The less, the better. (More in detail about that later for those of you who can "work" the wheels.)


Old-style Pinewood Derby Wheels	New-style Pinewood Derby Wheels. Notice the added weight, compared to the old-style wheels.

The other thing about wheels is that they are made in a multi-cavity mold. If you look on the back side of the wheels, you will see a little number which differs from one wheel to the next. The mold makes a whole bunch of wheels in one shot. Due to molding tolerances and slight differences between cavities, some are better-balanced and run straighter than others.

Rule Number One of Wheels: Select four wheels that run straight and true.

Go to your local Scout Shop and buy four or five boxes of wheels. Prepare an axle according to the directions later in this section. Now, sit down with your son and give him a stopwatch. Put a wheel on the prepared axle, hold the axle in your hand, and spin the wheel by dragging your index finger along the top of the wheel, fast. Have your son time two or three runs on each wheel. Set them down on a piece of paper with the times noted for each wheel. Some wheels will run true, while others will wobble and stop very quickly. Toss the "wobblers" in the "experiment" box and keep the ones that run straight and true. You should end up with at least six or eight wheels that will run 30 seconds or more before stopping and don't chatter or wobble as they spin down.