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Rule Pet Peeves

(An update of an article published in Volume 4, Issue 4 on November
17, 2004)

I receive lots of questions and comments from our readers about rules.
Many times the person is asking me for the rules for their race, or
for a clarification on a point. Sometimes, the person is griping
about the rules, especially when the race leader appears to them to be
misinterpreting the local rules.

In these cases, I can't do much more than lend a sympathetic ear.
Local rules are out of my control, and I certainly can't jump in the
middle of a rule dispute. But during these times I certainly do wish
that the local race leaders would take the time to document a clear
set of rules. So much miscommunication, grief, griping, and anger
would be mitigated by giving a clear set of rules to the race
participants well before the race event.(1)

But there is a more fundamental question that needs to be answered
when establishing rules. Even if the rules for the local race are
clearly documented, a valid question is "Why?" Why is a particular
technique allowed/banned? What is the rationale for allowing (for
example) an extended wheelbase? Why do we need to have 4 wheels on
the ground? Of course the list goes on.

In today's article I would like to explore several common areas of
pinewood derby design that are oftentimes regulated, and offer some
guidance as to whether these design techniques should or should not be

The purpose for rules is to make sure that the following criteria are

1. Will the car run properly on the track (proper width, height,
2. Will the car run without any damage to the race equipment (too
heavy, improper materials)?
3. Is regulation required to maintain a level of equity? Some
arbitrary limits - such as the five ounces maximum weight - are
imposed to limit the range of options, thus maintaining a level of
4. Is a particular technique commonly available to the other

Furthermore, the rules need to be in line with the rules of parent
organizations when participants at the local level will be moving on
to district level races.

Let's take a closer look at several rule areas.


There are many advantages to longer wheelbase cars (see Volume 2,
Issue 6 - "Modifying the Wheelbase"). So, should extended wheelbase
cars be allowed in all races? Let's look at the criteria from above:

1. Yes - the car will run properly.
2. Yes - no damage to track.
3. Yes - must be regulated for equity. A long wheelbase car has a
distinct advantage over shorter wheelbase cars.
4. Yes - anyone can extend the wheelbase using a hand drill or drill
press.(2) But some expense is involved.

Disallowing extended wheelbase cars is a limit set to maintain
competition. If the local club allows wheelbase modification, then
this should be documented in the rules so that participants know that
they are allowed to modify the wheelbase. Also, the means to extend
the wheelbase should be made available to all participants at a
workshop. By the way, some organizations run two classes of cars:
"Stock" - standard wheelbase only, and "Open" - Extended wheelbase


Many different lubes have been successfully used on pinewood derby
cars, including dry lubes (graphite and PTFE), liquid lubes (Krytox
100 and Silicon), and some unusual ones (Pledge furniture polish,
Armor All, and Talcum powder).(3)

1. Yes - the car will run properly.
2. Yes and No - if used properly none of these lubes will cause
damage. but if used to excess, many of the lubes can stain the track
(including graphite).
3. No - not required for equity. Many different lubes can be used
with reasonable success.
4. Yes - anyone can select an alternate lube.

Limiting the lube to a particular type is an arbitrary decision.
Certainly, to protect the track the rules must specify that excess
lube be removed before the car is turned in. But limiting the lube to
one type is not necessary. Different lubricants are widely available,
and in fact, the choice of lube is an area where human ingenuity comes
into play!

Having three wheels on the ground can be a speed advantage. But
beyond this, it is much easier to build a car with three wheels on the
ground than with four. Even when four wheels touch the ground,
normally three of the wheels hold the weight of the car while the
fourth wheel just barely touches.

1. Yes - the car will run properly.
2. Yes - no damage.
3. No - not required for equity. Although there can be an advantage
to running a three-wheeled car, the advantage depends on proper
4. Yes - in fact it is easier to run three than four on the ground.

Limiting the car to four wheels on the ground is arbitrary. Since it
is easier to implement, I strongly recommend allowing three wheels on
the ground.

Many car kits are equipped with wheels that are badly out of round.
To improve the performance, the wheels can be trued.

1. Yes - the car will run properly.
2. Yes - no damage.
3. Yes - required for equity. Rounder wheels are faster.
4. Yes - anyone can true wheels.(4) But some expense is involved.

Limiting the car to non-trued wheels does serve to maintain
competition. However, if your organization uses wheels that are
severely out of round, consider allowing trued wheels, and offer the
means to true wheels at a workshop.

Recently, many packs have instituted a minimum wheel diameter rule. I
believe the intent of the rule is to try to catch trued wheels.
However, this type of rule will not specifically catch lathed wheels,
but instead makes it more difficult on parents that try to prepare
wheels with a mandrel and sandpaper.

1. Yes - the car will run properly.
2. Yes - no damage.
3. No - not required for equity. Smaller diameter wheels run
4. Yes, anyone can change the wheel diameter, but determining the size
of the wheel requires a digital caliper.

Specifying a diameter restriction serves no purpose. If an entrant
wants to use very small diameter wheels, they will be less, not more

The speed of the car can be improved by reducing wheel mass through
tread reduction. This can be done in many ways including drilling
holes in the wheels, hollowing out the wheel, creating an "H" or "V"
tread wheel, and by narrowing the tread.

1. Yes - the car will run properly.
2. Yes - no damage.
3. Yes - required for equity. Some modifications can greatly improve
4. No - although they can be purchased, accurately modifying the
geometry of a wheel requires either special machinery and/or extensive
trial and error.

Since wheel modification is beyond the ability of many race
participants, I recommend limiting wheel modification to 'Open
Competition' races.

Aftermarket axles are available which require less preparation. Some
of the these axles can improve the speed of the car, but most just
simplify the car building process.

1. Yes - the car will run properly.
2. Yes - no damage.
3. Yes and No - some aftermarket axles may improve speed, while others
do not.
4. Yes - aftermarket parts are available, but an expense is involved.

The purpose of providing a kit is so that each participant uses the
same basic materials. However some kits provide axles that require
extensive work.(6) In these cases groups should consider offering
aftermarket axles to all participants, or change to a different kit.

Several people have mentioned to me recently that their rules state
that the front edge of the car must be at the bottom of the block. If
the block is tapered upward from the bottom to the nose, then the car
is disqualified. The rationale for this rule is that a car with a
front edge positioned higher on the block will have an advantage.

1. Yes - the car will run properly.
2. Yes - no damage.
3. No - not required for equity for the vast majority of tracks. All
modern tracks are equipped with spring-loaded gates which negate any
advantage of a high nose car.(7)
4. Yes - anyone can build a car with an upturned or high nose.

A restriction on the shape of the block is arbitrary and limits
creativity. I recommend not regulating the position of the front edge
of the car.

There are certainly other rules that should be reviewed to determine
whether there is a basis for the restriction. I encourage all race
leaders to thoroughly review the local rules and make modifications
where needed.

(1) In Volume 2, Issue 2 - "It's the Law! - A Sample Rule Set for Your
Pinewood Derby", I provided an outline for a complete set of rules.
Just fill in the blanks for your organization.

(2) The Pro-Body Tool is a drilling guide to accurately drill axle
holes with a hand drill. You can find it at:

(3) I do not personally vouch for any of these products except
graphite and Krytox 100. For more information on these products, see:

(4) The Pro-Wheel Shaver is a device for truing wheels. For more
information see:
In addition, trued wheels are available from many sources including
Maximum Velocity. See:

(5) The smaller the wheel, the more times it must rotate to make it to
the finish. Thus, a small wheel must rotate faster than a larger
wheel. The fastest wheel is of the largest diameter, the most
accurate, and the lightest weight possible. But to make a wheel
accurate, you must reduce the diameter. So, there is a trade-off
between wheel accuracy and wheel diameter.

(6) One of my pet peeves is the nail axles in the BSA kits. Removing
the burrs is a difficult process for many people. Certainly BSA could
include axles without burrs at little to no cost increase. But until
such a time, people will continue to purchase aftermarket axles such
as our BSA Speed Axles. For more information see:

(7) This was proven to be the case in "Cheater Bars - Do they Work"
posted at:

Read More at: Pinewood Derby Times Volume 10, Issue 4

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