There are six major factors that influence the speed of a Pinewood Derby car. Pay close attendtion to all six of these and you can build a winning car.
Major Speed Factors:
1. Body Design
2. Weight Placement
3. Wheel Preparation
4. Axle Preparation
Advanced Speed Techniques:
1. Rail Rider Alignment
2. Rear Wheel Canting
3. Advanced Friction Reduction
During the race the wheel hubs will rub on the axles. This unwanted friction contact cannot be avoided. However, if you have properly repaired and polished your axles and wheel hub bores then this friction is reduced. But even that is not enough.
We must thoroughly lubricate all friction points before putting on the wheels. Your scout rules will probably require that you use a dry lube. If so, use quality graphite, such as
Monkey Dust dry graphite powder. If, on the other hand, your rules allow for the use of oil then you should consider taking advantage of that by using a super lubricant like NyOil or Krytox.
The Derby Monkey Garage uses DuPont Krytox® GPL 100 whenever oil is allowed. This is a highly-refined synthetic thin-film lubricant with an ultra-low viscosity. When this stuff is properly applied it equals or outperforms any dry lubricant on the market including graphite. Krytox is much easier and faster to apply than graphite.
It is also almost undetectable by derby officials. As a matter of fact, Pinewood Derbies should adopt a Krytox only policy. When properly applied, Krytox is much cleaner and leaves no trace on the tracks.
This stuff is also perfect for your nice paint job. Graphite will stain and ruin a light color paint job but Krytox will not.
READ MOREMonkey Dust
It is very important that you first treat the axles with graphite. This is an often overlooked procedure and most experts agree that this is an extremely important process. The graphite must be properly worked into the axle. No matter how fine you polish the axle shaft there will still be microscopic scratches that will add friction. By working in the graphite, it fills the minute scratches and helps protect against this unwanted abrasion. The Derby Monkey Axle Lube Kit is an excellent tool for thoroughly treating axles.
Treating the Wheels
Extra Tip: When inserting the axle, make sure that the axle tip does not rub against the inside of the hub wall. This will place scratches on the surface that you have worked so hard to polish. These new scratches will create unwanted friction. You can’t just squirt a little graphite in the hub and that’s it. You must pack the graphite tightly in the hub until the hub is completely packed full of graphite. Again, don’t worry about being wasteful.
After the hub is packed, carefully insert the axle in the wheel. A lot of the graphite will be pushed out of the other side of the hub but that’s OK. Spin the wheel several times on the axle to help seat the graphite. Graphite has a break-in period of 4 to 6 runs so always spin the wheels multiple times. Then mount the wheel and axle on the car. Be careful so that you don’t get graphite on your nice paint job.
Extra Tip: Keep your graphite and lubed car in a dry place. High humidity will actually dampen the graphite causing it to gunk-up and decrease your speed.
Now, roll the car back and forth on a clean flat surface. If you have a test track, make 3 or 4 practice runs. This further helps to seat the graphite. Then remove the wheels and start the wheel treatment process all over again.
Extra Tip: Other parts to consider lubing with graphite are:
• The car body where the hub rubs
• The inside of the wheel hub
• The inside of the wheel edge
• The wheel surface
Every little bit helps.
After the last wheel lube, you car will need what is comparable with 5 practice runs to break-in the graphite.
Wipe the car down and remove as much loose graphite as possible from the body and outsides of the wheels so that it won’t get on the track. Then put the car away and don’t touch until check-in time.