New Pinewood Derby Wheels
The pinewood derby season
for 2009/2010 has brought the
introduction of the new official BSA pinewood derby
wheel for the pinewood derby kit. Although not all
kits will have the new wheels for the 09/10 season,
there will be enough available that you need to know
everything about them. Let us introduce you to the
new BSA pinewood derby wheel. As of this writing, the
best way to determine if the kit has the new wheels is
to look on the outside of the box for the following
number code stamped on the box, "IN0809", upside down in
this case. The old boxes have a simple "Z" marked on
Stamp Number on Boxes
with New Wheels
(Check to be sure before purchasing at local store)
First, a description of the new wheels. The new wheels,
most importantly, are lighter than the old wheels. The
new wheels average about 2.6 grams each while the old
wheels averaged 3.6 grams each. This is a significant
weight reduction and would alone make the new wheels
faster. Part of the weight reduction has been the coned
inner wheel hub which has been reduced significantly as
shown below. (New wheel on the left)
Coned Wheel Hub in New Wheel on Left
The new wheels also have
been re-tooled so that there are three mold marks inside
the wheel well as opposed to a single large mold mark on
the tread surface as shown below. The old wheel is
on the right and the mold mark is near the top of
the picture. The new wheel is on the left and has
a clean, unblemished tread surface.
Mold Mark on Old Wheel on Right
Round and Round We Go (Or Maybe Not???)
The new wheels still have
some radial imperfections as they are not perfectly
round. They average about .005" differential across the
wheel surface but it is better than the old models.
This lack of perfect roundness can be corrected with the
Pro Shaver XT or by purchasing the new DerbyWorx
Precision Stock or Pro Stock wheels which have been
machined perfect on the outer tread surface. This
provides a smooth, stable and fast ride down the track.
Just as in the old wheels, the new wheels
are made from multiple new molds, in this case, numbered
1 thru 16. The wheel bores vary by as much as .01"
from one mold to the next and you need more consistency
to have all 4 wheels sitting evenly on the track.
One can ream the wheel bores with the Pro Hub Tool to
get the wheels to a consistent size (next section) or
one can use wheels from the same mold number.
Better still is to have the wheel bores machined to a
perfectly consistent size which DerbyWorx does with the
Pro Stock Wheels.
Difference in the New Wheel however...
Step in the Outer Wheel Hub of the New BSA Pinewood
wheel is lighter and has a better outside tread surface
but it has an unusual outer hub design. It
actually has a step or ledge in the outer hub (new wheel
on the right) which presents no obvious speed advantages
but does have some potential disadvantages.
Step in Outer Wheel Hub of New Wheel on
creates a second contact point on a beveled axle head
and would contact it further to the outside of the axle
head, meaning more surface contact area. With no
obvious speed advantage to the step, the predominant
speed tip for the new wheel is to get rid of the step
altogether. The Pro Outer Hub Tool seen below was
initially created to clean up the outer hub for the old
wheel but is nearly perfect for the elimination of the
step on the new pinewood derby wheel. The outer
hub tool needs to be sharpened first and that can be
easily performed with a file which we will show you
after we discuss reaming the wheel bores with the Pro
Wheel Bore Reaming
wheel bore, simply put, is the inside of the wheel where
the axle goes. Molded
Pinewood Derby car wheel hubs can vary in size by as
much as .01" and you must resolve this situation
to have the smoothest fit of the axle into the wheel.
The Pro-Hub Tool allows you to ream the wheel bore to
the same size or to at least select wheels from your
assortment that have a similarly sized bore radius.
This is a very important alignment tip as it allows the
car to sit evenly on all 4 wheels with equal distances
from the axle and wheel hub to the track. You will need
the Pro-Hub Tool to complete this speed tip. To perform
each wheel by sliding it onto the tool pin of the
Pro-Hub Tool (flat side) as shown below. If the wheel bore
is too small for the tool, use steady hand pressure and
a twisting motion to work the wheel on to the tool.
Remove the wheel and repeat 3 times.
Pro Hub Tool (Flat End)
completed, choose another wheel and repeat step 1.
Outer Hub Tool
(Note: The Pro
Hub Tool is required for use with the Pro Outer Hub
The Pro Outer Hub
Tool will surely become one of the most popular tools
for the 2009/2010 pinewood derby season for the
Ensures accurate rotation of the wheel by
squaring the outer wheel hub to the wheel bore
for proper mounting of the wheel on the Pro
Reduces friction between the axle head and the
outer wheel hub by eliminating flaws on the
outer wheel hub and, most importantly
Removes the step in the outer wheel hub on the
new wheels which are a potential double friction
contact point with the axle head.
that the Pro Outer Hub Tool is intended for use on
BSA wheels only. It is not recommended for use
on wheels made by any other manufacturer.
Sharpen the edge of the Pro Outer Hub Tool
you are removing the step in the outer hub on the
"new" wheels, you will first need to sharpen the
cutting edge on the outer hub tool. To
accomplish this step, merely file the back side of
the cutting edge with a flat file until you have
created a small angle to the back of the cutting
edge. A picture of the outer hub tool with the
edge sharpened is shown below on the left compared
to a regular cutting edge on the right. The
specific angle is not important. You do not
need to sharpen the cutting edge of the outer hub
tool if you are performing modifications to the
Instructions for Using the Pro Outer Hub Tool
Remove the protective cap from
the square or flat end of the Pro Hub Tool and
ream the wheel bores of each wheel per the
Slide the Pro Outer
Hub Tool onto the pin of the Pro Hub Tool with
the cutting edge outwards. To minimize the
risk of injury, leave the protective cap on the
coned end of the Pro Hub Tool.
Place a wheel onto
the pin of the Pro Hub Tool, spoke side first.
With one hand
holding both the Pro Hub Tool and the Pro Outer
Hub Tool, press the wheel against the outer hub
tool cutting edge with the other hand. Rotate
the wheel three complete revolutions.
Check the outer hub
to view your progress. If you are
modifying the "old" wheels, you will not need to
make too many revolutions with the outer hub
tool to complete the process. If you are
removing the step in the "new" wheels, it will
take quite a few more revolutions to get the
outer edge of the hub even with the inner edge
of the hub and completely remove the outer step.
Continue to check your progress after a few
revolutions to make sure that you do not remove
any excess material past the removal of the
step. The finished product in either case
of the "old" or the "new" wheels should look
like the wheels shown below. The non-modified "old"
wheel is on the left and a modified "new" wheel
is on the right.