Winning Pinewood Derby Cars
This article was written to
help Dad and Scout build a reasonably fast Derby car. The
steps are in order. This should make the process easier and
more enjoyable. I have also tried to identify all of the
steps that the scout can safely participate in. If any
construction technique in this article violates your local
Derby rules, do not use it.
Prepare the Axle Supports (holes) in the Block
The axle slots or holes must be square with the block.
Using a drill or drill press, drill new axle holes using a
#43 or #44 bit (#44 is the axle size for the new 1998 kits).
We use the #43 so that the axles easily fit into the axle
holes (Later you will see how we secure the axles into the
holes -- all this makes it possible and easy for the scout to
install and secure the axles/wheels). If legal under your
local rules, lengthen the wheelbase -- the longer wheelbases
seem to be more stable. I also drill the right front axle
hole higher to lift the right front wheel off the track (3
wheels, rather than 4, means a slight reduction in friction,
but more importantly, it provides a place to put your worst
wheel. It seems there is always at least one really bad wheel
in the kit).
What you want is wheels that run true
on the axle
and "absolutely" do not rub the car
body when running.
Build glue application channels for gluing in axles. This
is simply drilling a 3/32 hole or cutting a slot from the
bottom of the car into the axle channel. This makes it real
easy for the scout to secure the axles in with a drop or two
of glue after all construction and testing have been
Build graphite application channels for lubricating the
axles and wheels. This is simply grinding or cutting away a
small area of wood on the bottom of the block below the
axle. It makes it much easier for the scout to apply
graphite to the axles and wheels after all construction is
Create weight storage compartment
Pick your weights ahead of time and make a hole(s) or pit
for the weight at this point. You will probably be adding
from 1.5 - 2.3 ounces of weight. You can put weights in
anywhere, but the experts say the weight placement should be
biased toward the back of the car making the balance point
1" to 1 1/4" in front of the read axle. I totally
agree with this weight placement.
The images below provide what I consider to be the best idea
for weight placement. The holes for the weights (3/8")
are drilled to accept standard tubular weights available
from your local Boy Scout supply store. This way the scout
can safely participate in adding weigh to his car. A few drops of glue will hold the weights in and you can putty
over the holes before painting.
Build the car body
This is where any age kid can get really involved and
have lots of fun. Keep the car shape as simple as possible so
the kids can actually help do the work. Apply the design to
the block, carve (not for kids), saw, sand and paint, etc.
The kids can really have fun here and, for the most part,
will not negatively affect the performance of the car.
Just a couple of tips here: (1) Make sure to take off a
good bit off wood, because you will want to control the
amount and location for added weight. (2) My fastest cars
are the ones with the skinniest and slickest profile.
Minimize rolling friction
True and polish the wheels and axles.
(Remember, one wheel is going to be off the track,
so pick the best 3 wheels and axles to start with. You can
roll the wheels on a glass table & spin the wheels and
axles in a drill to find the best ones) You can really have
some fun with the scouts when testing the wheels on a table.
It's like a race in itself. Do not alter the
basic shape of the Boy Scout kit wheels -- you only want to
remove any imperfections and smooth up the finish.
True and polish the wheels using a drill and vice setup.
You clamp the drill in the vice and spin the wheels using a
wheel auger (available from your Boy Scout supply store).
True the wheels to round using a small flat file then polish
with a 1500 grit wet-sand paper. Make sure you keep the paper
wet -- this cools the work and also provides an exceptionally
smooth end result.
The axles require special treatment. A drill/dremel drill
press setup is required for all steps. Using a very fine
ignition file, remove the flashing from the inside head of
the axle and shaft (this is where you will want to create the
angle on the inside of the axle head). Polish with the 1500
grit wet-sand paper and finish off with chrome polish and a
soft cotton cloth.
- Weigh all car parts and get the car to the right weight
and finish off any needed sanding, painting, patching,
detailing, etc. The scout can do most all of this with very
little assistance. You do not want to have to do any of this
type of work after the car is assembled.
- Rub graphite on the car body where the wheel hub runs
against it. Rub it in really well. Enough will stick to
provide a really slick surface for the wheel to rub against
if the wheel happens to hit the car body during the race. The
scout can do this with minimal assistance.
- Insert the wheels and axles into the axle holes (do NOT
glue yet). We use a tongue depressor (1/16" - 3/32"
thick) to set the wheel clearances. The scout can do this
easily, since you prepared the special axle holes!
Wheel clearances are critical!
You want plenty
of slack for the wheel to move freely.
- Test the assembled car (no glue yet) on an inclined
table -- glass is preferred. Test your new car against the
baseline (last year's fast car). The table test will not tell
you which car will be fastest on the track, but it will help
you "tune" your car to be as fast as
possible. The scout will really enjoy this part (as long as
you don't over do it). If you have access to a track, do
final testing on the track before the race. See tuning
- If you have to take the wheels off for any reason. Mark
the "top" of each axle and put the wheels and axles
into baggies labeled LF, RF, LR, RR. This makes sure you get
the wheels and axles back onto the car in the right position.
You will want to have some graphite in the bags also.
- Apply glue in the glue application channels to secure
the axles. If the scout is careful, he can do this with
- Continuously force graphite into wheel and axle areas
and spin them till they are worn in really well. Also rub
graphite onto the wheel itself. You can't put too much
graphite on -- any excess will just fall out and blow away.
And, you can't spin the wheels too much -- the kids are great
at spinning the wheels.
Tuning -- Axle and wheel alignment
A really fast derby car must have true running axles and
wheels. Sometimes this happens by accident, but it is best
to make sure the axles and wheels are running true by tuning
the car. The scout can have some fun here but not if it's
over done. Dad can do some tuning and the scout can do the
kitchen table races.
Some of the links below go into great detail on axle
alignment, but we found these to be too detailed for either
me or my son to follow. The use of wax paper shims might be
o.k., but only to correct a really bad axle problem --
aligning all axles and wheels using this method is
difficult and boring. I doubt you would ever find a scout
that would consider this a fun exercise.
Note: There are several sources for specially tuned
axles and wheels -- most of these special components would
be in violation of local race rules, so don't even consider
it. If you and your scout can't do the work yourself, what
would be the point?
The idea is to have a car that is in near perfect
alignment. Meaning that the car runs basically straight and
that the wheels do not consistently ride against car body or
axle head (especially against the car body!)
Some of the things you can do to tune or improve the
List of Things That Really Appear to Help
- Perfect drilling of axle holes. The jury is out on
angled axles -- it may very well be that this is the
simplest way to produce a fast wheel/axle arrangement.
- Go back to square one and make sure to start with good
- Make sure the better of your wheels and axles are being
- In some cases switching your axles and wheels around may
- If you have a wheel that insists on rubbing against the
car body while rolling, use the wax paper shims to shim the
axles "up" | "back" | "up and
back". (See axle alignment links below).
- If you have a really bad wheel, re-polish it and try
- Continue to roll assembled car and adjust the wheels and
axles until you have a car that runs true. Continue to test
it against your baseline car in a mini kitchen table race.
- One front wheel off the ground.
- The axle polish and angling of axle head using ignition
file, 1500 grit wet-sand paper and chrome polish.
- The truing and polishing of wheels using a flat file and
1500 grit wet-sand paper.
- Sleek body profile.
- Weight near rear of car.
- Rubbing of graphite on the car body where the wheel hub
hits the body.
- Testing cars on inclined table making sure the car rolls
- Wax paper shims to correct an out-of-line axle (if
- Rubbing the wheels down with graphite.
- Lots of graphite and spinning the night before the race.
List of Things That Appear Not to Really Help
- Glue bead (covered with graphite) on body for wheel to
- Angled axles? (Again, not quite sure on this one).
Actually this is one of the biggest boosts -- we were hoping
you would not read this far. Drill the axle holes in the
body at a downward angle of like 1 degree. This forces the
wheels to "ride up" toward the axle head where it
encounters much less friction that what it does when the
wheel rubs the car body!
- Polishing axles with graphite pencil.
- The use of hubcaps.
Here are a couple more Pinewood Derby sites worth reviewing.
ABC Pinewood Derby - Your “How to” guide to the Pinewood Derby Car. Everything you need to design, build, win and even manage a Pinewood Derby race. (http://www.abc-pinewood-derby.com)
Pinewood Derby Racers…How to Win Your Pinewood Car Derby! - The excitement of competition! A detailed, inspirational booklet that explains the specifics of building your pinewood car for speed. Make your car the fastest it can be with secrets that will give you a winning edge! We speak out of the experience of four years of consistent wins. Useful for the Cub Scouts or Boy Scouts Pine Car Derby Royal Rangers, Royal Ambassadors, Awana Grand Prix, Shape N Race, Kub Kar Rally and other groups. (http://win-edge.com/PinewoodDerby.shtml)