| Pack 373's Pinewood Derby Pages |
| "A little, healthy competition is a necessary part of building strong character." |
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| Wheels |
Now it is time to prepare the wheels.
The casting method used for the wheels yield a very good quality. The wheels are for the most part round and balanced, and they are made to strict tolerances of size (diameter, width, hole diameter, and weight).
Very little needs to be done to the wheels other than sanding the rolling surface to remove "flash" left over from the casting process. This can be accomplished in many ways:
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My favorite method is clamping the wheel by the axle stem into the chuck of a drill. Just tighten finger tight so as to not damage the plastic. Run the drill at a low speed, and hold a piece of 800 - 1000 grit sandpaper against the rolling surface of the wheel. Only do this for about 10 seconds. Running the drill longer than 10 seconds will cause it to heat up and damage the axle shaft. |
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You can also do this by hand sanding the wheel using a light touch with 800 - 1000 grit sandpaper. I do not like this method because it can cause flat spots on the wheel surface if you sand too long in one place. If you do not have a drill available, this method is better than nothing. |
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Wheel mandrels that hold the wheel more safely in a drill are commercially available, but they are expensive. You can simulate the mandrel by wrapping a little masking tape around a spare axle shaft and wedging the wheel onto the enlarged surface created by the tape. This works well if you are careful, use a light touch with the sandpaper, and are careful not to get the wheel sticky from the tape residue. |
Some Packs allow detailing of the wheels by painting the "wire" rims and enhancing the "raised letters" of the tire. We do not allow enhancing the wheels because the added weight of the paint can actually throw off the "balance" of the wheel if it is not done perfectly. We also do not allow "hubcap" stickers because added graphite lubrication can be hidden under the sticker, and if the sticker does not dome out enough to clear the axle head, the axle head will bind against the sticky part and slow the car down.
Further enhancements that we do not allow are thinning and narrowing the wheel. Thinning of the wheel is done on a lathe and involves removing plastic from the interior surface of the wheel. This action is to reduce the weight of the wheel, thus reducing the action of friction, and it also produces a better "balanced" wheel. Thinning a wheel involves advanced skills and incredible patience. The benefits of thinning are not enough to warrant the time and skill involved.
Narrowing the wheel is easily accomplished by a drill or lathe. It simply involves changing the width of the wheel to any size smaller than the stock width by sanding, grinding, or cutting away the excess from the inner edge of the wheel. This produces a narrower rolling surface of the wheel, thus reducing the effects of friction. "Rounding" and "V" cutting the rolling surface of the wheel also produce less rolling resistance, but are also disallowed.
I have tried these methods myself, and it took nine tries and almost 6 hours to produce four identical wheels. I have been doing intricate woodworking for many years, so it is easy to see the time and skill involved.
Be warned, wheels are inspected for illegal enhancements. Don't be disqualified from racing because you are trying to gain an unfair advantage.
Tip: Application of a non-solvent based, quality wax (or metal polishing compound) to the surface of your wheels produce a nice shine, and provide a good grip on the track surface. Application of the wax would be in the same manner as sanding the wheels. A small amount of wax goes a long way, so use it sparingly. Buff the wheel to a high gloss. Too much wax and the wheel is sticky, too little and the wheel is uneven in shine. Both of these extremes will cause in increase in friction. You may want to use a spare wheel to practice on, as this is not an easy task to master the first try.
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