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Do's and Don'ts for Pinewood Derby Race Leaders
By Randy Davis

On March 13, 2011 I received an e-mail from an upset customer. They
had used some of our BSA wheels in their pack race, and did well
enough to go to their district race. But at the district race they
ran into a problem. The race inspector disqualified a large percentage
of the cars (over sixty cars were disqualified) because the wheels
were too narrow. The customer's car was one of the 60. I asked the
customer to send me a copy of the rules for the race. Amazingly
enough, a minimum wheel width was not specified in the rules. So, I
told the customer that there was no reason for the disqualification,
and that they really should notify the district officials of the

Then on Monday, I received three phone calls and e-mails from
different customers regarding the same problem. All of them realized
that they had been treated unfairly. One of them described how the
official would look at the wheel, and then if it looked home processed
it was not measured (even though some sets of home processed wheels
where clearly very narrow). But if the wheels were nicely machined,
then the inspector measured the wheels, and used the non-documented
specification to allow or disallow the wheels. Amazing.

I don't know the motivation of the inspector at this race. Two of the
customers thought he had a vendetta against Derby Worx (one supplier
of machined wheels), and another thought he was trying to eliminate
competition for a friend's son. Maybe he just got out of the wrong
side of the bed that morning. But whatever the reason, at least sixty
kids and their parents went home disappointed because they could not

If this was a one in a million occurrence, then there would be no need
for this article, but unfortunately this type of aberrant inspection
occurs all too often. I hear of many instances where undocumented
standards are used at the inspection, rules are changed within a few
days of the event(1), or rules are not made available to race

So, in an effort to help prevent this type of occurrence, I would like
to share the following principles for running a fair race.


Every race participant must be given a copy of your local rules. These
rules should be provided as a hard copy when the kit is distributed,
or posted on your group's web site in a very conspicuous location.

If you are using the rules from a parent organization (such as a BSA
district or council), replicate the rules on your group's web site in
a conspicuous location, or provide a hard copy. Do not tell parents
to, "Just look on the district's web site". Finding rules on some of
these sites can be challenging - don't make your members struggle to
find the rules for your race.

Make sure that the rules you are using are clear and up to date. If
you want to ban or allow a particular technique, then specifically
state that the technique is, or is not allowed. For example, if you
want the axle slots on the kits to be used, then state, "The axles
must be mounted in the axle slots on the block." Don't say, "The
block from the kit must be used", because this would allow the builder
to drill axle holes on the other side of the block.

Here is a minimum list of techniques that should be specifically
stated as being allowed or disallowed:

- 3 or 4 wheels on the ground
- Axle slots or holes
- Existing or modified wheelbase
- Allowed/banned lubricants
- Grooved/non-grooved axles
- Weight-reduced/full weight wheels
- Narrowing of wheels
- Tread modification

Certainly there are other techniques to consider, but documenting the
techniques in the above list will greatly clarify what can and cannot
be implemented by the car builder. But be careful, if a technique is
banned, then the race inspectors must check for the use of that
technique. So make sure there is a method for inspecting whether or
not the technique is used.(3)

Once the rules are distributed, they cannot be changed. If rules are
changed after the kits are distributed then those people that don't
procrastinate will be penalized. Just plan to make the rule change
for next year's race.

Inspecting for non-documented items is one of the most common
complaints I hear from parents. I call it "legislating from the
bench", because it is essentially a judge (who is supposed to rule on
the law) making a law (which is not in his/her mandate).

If a particular technique or specification is not documented in the
rules, the inspection committee must not inspect for that technique.
For example, if the rules do not state that all four wheels must be on
the ground, then three wheels on the ground must be allowed, and the
inspection committee must not check for this technique. If there is
no specification in the rules for wheel measurements, then don't
measure the wheels. I think you get the idea.

Every technique banned in the rules must lead to an inspection step.
If an inspection is not performed for each banned technique then the
"honest" car builders are penalized.

The method of inspection must be easy to perform, and very repeatable.
The best way to accomplish this is with purpose-built gauges. The
most common gauge is the "Go/No-go Box".(4) This gauge quickly
determines if the car meets all of the dimensional specifications.
Another gauge is the Wheel Go/No-go Gauge.(5) If the rules state a
minimal wheel diameter or wheel width, then a Wheel Go/No-go Gauge is
used to determine if the wheel is legal. Do not use a digital caliper
for this check. Digital calipers are prone to error, as each wheel
must be measured in the exact same location, with the proper angle,
and with the proper pressure. If any of these are inconsistent, the
measurements will be prone to error. This is especially true of wheel
diameter; the wheels are flexible and too much pressure on the caliper
will cause the diameter to read smaller than it actually is.

Some techniques cannot be readily tested at the weigh-in. These
include: grooved axles, the use of bearings or bushings, wheel weight
reduction, et al. If these techniques are banned by your rules, then
a post race tear-down will be required. This tear-down consists of
removing one or more of the wheel/axle sets from the trophy-winning
cars. The wheels can then be easily weighed, measured and inspected,
and the axles can be inspected. If a car is found to violate the
rules, then the car is disqualified, and the cars below move up a step
in finish order.

I encourage all race leaders to review the rules for your race for
completeness, accuracy, and availability. Then review your inspection
process to make sure you are inspecting to the rules. These simple
steps can help make your race more organized and enjoyable for all.

(1) Several times people have told me that they built an extended
wheelbase car, which was legal at the previous year's event. But two
days before the race, new rules were issued which required standard
wheelbase cars. So the racers had less than two days to build a new

(2)"Just use the rules in box" is a common phrase that participants
are told by the race leader. Of course, the rules in the box (whether
it is a BSA kit, Awana kit, etc.) are quite open with little
restriction. But when the car is inspected, the child/parent is told
by the inspector, "You can't do that. That's illegal."
"Where is that documented?"
"Right here", says the inspector.
"But I didn't get a copy of that; I was told to use the rules in the
"Sorry, I can't help that", says the inspector. "Next car!"

(3)A common rule is "Only dry lubes can be used". But how do you
inspect for this? Even if you do a post race tear-down, determining
that a liquid lube was used is very problematic. Therefore, I am a
proponent of not regulating lubricants.

(4) A Go/No-Go Box is offered by Maximum Velocity.

(5) A Wheel Go/No-Go Gauge is offered by Maximum Velocity.

From Pinewood Derby Times Volume 11, Issue 1

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