Tips and tricks:
By Joe Horst
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I have been running Pinewood Derby’s for years, my son went through 5 years of cub scouts, after the first year, and watching a big fight of an unorganized derby, I decided to take over and run it myself. After the purchase of electronic finish line and computer interface, and some organization, I started putting on very organized and FUN pinewood derbys. Through all of this and many practice days with the finish line (the finish line times to 1/10,000s of a second) I learned some things that help make a pinewood derby car fast!!!
The following are some of the things we did to our cars, while some are my opinion, we were very successful at the Derbys.
Keep the car as flat as possible, some literature says wind resistance plays little or no part, but the fastest cars I have seen (including ours) were very flat. The electronic timer we use times up to 1/10,000's of a second, I have seen several races won by less than 2/10,000's of a second!!!
Do NOT make the car sit lower than normal or it can rub against the center guide and this will slow the car a bunch!!!
Take the burrs off of the axles (the nails) then put them in last after all the body work is done. Paint the car with something that cleans easily or (use a skin) as you will use a lot of (black) graphite after the car is all done and it will make the car look bad if you can't clean it off.
Drill holes right in front of and behind the rear axle (crossways) and drip lead into them (I use fishing weights and a small torch). Of course this is done before the car is painted and axles put in. You want the car to weigh between 4.7 and 5 ounces. I have tried different weights on the same car and once you hit about 4 3/4 ounces, it has hit its prime weight, most rules do not allow over 5 ounces. You want the weight at the rear of the car, this IS an advantage, but not very far behind the rear axles or it will raise the front wheels off the track.
Put the wheels and axles on last, be sure all the burrs are of the nails and polish them so they are very smooth, if your rules allow, round the tires, put them in a drill and smooth them as well, if your rules do not allow you to round the wheels, (most don't) then smooth the inside of them and tilt them very slightly, when you set the car on a smooth and flat surface, you will be able to see just a little bit of light on the outside of the wheel, the less wheel that touches the track, the less resistance it will have.
Spin all 4 wheels on one finished axles, find the three that spin the best and those are the three that touch the track.
!!!! One of the front wheels (it does not matter which one) gets a hole drilled for it just higher than the other three. This wheel is only used to guide the car and should never touch the track. When you set the car on a flat surface, you should see light under this wheel, but it should not be much higher than the other wheels and it should be straight and polished on the inside as well. (I use a drill press and drill my own axle holes, while it is more accurate, it can be very difficult)
Also very important >>>> Once everything is done roll the car across a very smooth and clean floor, it must roll very straight, if it does not, find the wheel that is not in straight and fix it, if it does not roll straight, it will try to run against the center guide all the way down and will slow it considerably.
At this point start lubricating the axles and also rub the inside of the wheels with lubricant. Spin the wheels and continue to lubricate (I use air pressure to spin the wheels, but not too fast or it will melt the plastic) If you do not have air pressure, have your son do it by hand 15 minutes on each wheel the night before the derby (he should do this anyway).
Most derbys do not allow lubricant once the cars have been impounded, if they do allow it, lubricate the wheels right before the race and spin the wheels a bunch, then only once more during the race halfway through, we tested this a bunch, and right after the axles are lubricated it takes about 3 to 4 races to reach the fastest times and they will hold that for another 2 or 3 races before they start slowing, our races usually consist of each car racing 12 times, with an electronic timer and computer interface, this is very possible, on a very large group (like regional’s we only run 8 races and lubricating the wheels in the middle of this is not necessary).
JJ built his entire car in his last year of cub scouts and still won our packs derby and finished second in regionals!!! But he watched everything we did in prior years and I let him do a great deal of the work those years.
Well that should give you something (a little) to work with!!!!
Notes on the derby itself:
Be sure your pack uses an electronic timer, this saves a lot of arguments and you can not eyeball a race that is within even 10/10,000 of a seconds and it happens often.
One of my other rules is that all of the boys walk out with the same prize, I always used little trophies or plaques, they can say "first", "second", or "participant" but they must be the same; these two things will keep it fun!!!! This is what it is all about!!!
I also do NOT recommend running eliminations, this will allow some kids to not run as many races as other kids and that takes the fun out of it.
Below are the rules that I use at our Pinewood Derbys:
Your rules may vary, but these worked well and kept the derby fun!!!
It is in my opinion that using only BSA cars is very important, it keeps the playing field more even and of course it supports the Boy Scouts of America!!!
I also feel strongly on requiring the boys to wear their uniforms, however I did not ever prevent a boy from competing when he didn’t, but they should be strongly encouraged to do so.
Pinewood Derby Rules
¨ Each participant may enter one (1) car. The car must be built for the current year of competition and not raced in previous years. The Cub Scout should play an active role in the design and construction of the car. It is understandable that a younger Cub Scout will need more assistance from an adult and we encourage this along with explanations for the reason the wheels are sanded, axles are polished, etc.
¨ The Cub Scout needs to be present and in uniform for the car to compete.
¨ Wheel and axles must be lubed before entering the building before the day of the race. No lubrication will be allowed to be added, inside or outside the building, once the car has been impounded.
¨ After registration, inspection and weigh-in the car will be impounded. A car losing a wheel or any part that prevents running can be repaired after weigh-in, if damaged during a race. Repairs have to be made by the car owner, a parent, or an official.
¨ If car leaves the track in two (2) consecutive races, it may be disqualified.
¨ The starting pin - The cars will rest against a starting pin; therefore it is advisable that they do not come to a sharp point in front. Due to a short starting pin, the front end should not be any higher than ¼” above the axle line.
¨ ONLY the official Cub Scout Grand Prix Pinewood Derby kit should be used.
¨ Width – overall width will not exceed 2-3/4”. Width between wheels will not be less than 1-3/4”.
¨ Length – overall length will not exceed 7”.
¨ Bottom Clearance – Clearance between car and track will not be less than ¼”.
NOTE: Some tracks may require a 3/8” clearance.
¨ Weight – Will not exceed 5 ounces.
¨ Height – Will not exceed 4”
¨ Only official Cub Scout Grand Prix Pinewood Derby wheels and axles are permitted.
¨ Wheels - You may not change the wheel dimensions. Wheels may not be rounded, pointed, concaved, shaved or otherwise modified. You may, however, sand the tread or tire contact area of the wheel to smooth out the rough spots. Wheel bearings, washers, and bushings are prohibited. The car will not ride on springs of any type.
¨ Axles - The axle grooves provided in the block of wood do not have to be used. Wheels will not exceed past the front or rear of the car body. Wheel covers or hub caps are prohibited, the head of the nail must be viewable for inspection. The axles (nails) maybe polished and stamping imperfections removed but the shape and size of the head may not be altered.
¨ Lubricant - The recommended wheel and axle lubricant is dry, powered graphite.
¨ Other Items – Details such as steering wheel, a driver, and decals are permissible as long as these details do not exceed the width, length, height, clearance and weight specifications. All details must be securely attached to the car.
¨ All cars will be free wheeling with no starting devices. Magnets and slip weights are prohibited. All weights must be securely attached to the car.
¨ Inspection: Each car must pass an inspection by the official Inspection Committee before it may compete. The inspectors have the right to disqualify those cars which do not meet the rules and specifications outlined above, even though your car passed the inspection at the Pack or District level. If a car does not pass inspection, the owner will be informed of the reason for failure and will be given a time within the official registration period to make adjustments.
ALL DECISIONS BY THE RACE OFFICIALS ARE FINAL.
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