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(Note:
To incorporate the Rail Rider™
technique, you must be able to cant your wheels, in
other words, the wheels will not be riding flat on the
track. It is also best if you can keep one of the
front wheels off the track but this is not an absolute
necessity. If you can have one of the front wheels
off the track, then the opposite front wheel which is
touching the track is referred to as the dominant front
wheel. The preferred method is to have the
opposite wheel off the track if it is legal for your
race. If both front wheels are touching the
track, then push your finger lightly against the front
end of the car to see if either of the front wheels is
taking more of the pressure than the other. If so,
then use that wheel as the dominant front wheel.
If both are perfectly even, then choose either of the
front wheels to be the dominant front. In either
case, the non dominant front wheel will be aligned to go
straight down the track as much as possible and the
dominant front wheel will be angled to create the rail
rider.)
Implementing the Rail
Rider™ Technique
and a New and Easier Way to Align Your Pinewood Derby
Car
It would be great if we
could build a perfectly aligned car and run it on a
perfectly aligned track for a perfectly straight ride
down the hill. We could stop worrying about hitting the
center guide rail at all. This is of course impossible
unless God starts building pinewood derby cars and not
just the trees themselves. So, what can we do to
minimize either the amount of contact that a car has
with the center guide rail or minimize the loss of speed
associated with that contact? To answer that, let us
introduce you to the Rail Rider
™ technique. (Term
trademarked by DerbyWorx and Warp Speed, Inc.)
The easiest method is
with the DerbyWorx Pro Rail Rider Tool in combination
with the Pro Axle Press. The Rail Rider tool shown
below has two sides marked 1.5 and 2.5. The 1.5 is for
the degree of cant for the front axles and the 2.5 is
for the degree of cant for the rear axles. Keep in mind
that this method requires that you complete all of the
polishing and friction reduction modifications to the
axles before implementing as it would be next to
impossible to perform same afterwards.
Place a mark on the axle
head with a sharpie and insert the axle into the pro
axle press with the mark pointing straight downward as
shown below. Keep about 1/2" of axle showing
outside the axle press to allow room for the rail rider
tool.
For the rear axles,
place the Rail Rider Tool over the Pro Axle Press with
the side marked 2.5 sliding over the axle shaft. (We
marked the pro axle press with a sharpie ourselves to
show the angles better) Make sure the mark on the
axle head remains pointing straight down and that the
axle head is snug against the tool as shown below.
Then strike the top of
the Rail Rider Tool with a hammer sharply three times.
This should create a 2.5 degree bend in the axle similar
to that shown below. Then perform the same steps with
the front axle except use the 1.5 degree side of the
Rail Rider Tool. The picture shows a polished axle
with a perfect 2.5 degree bend for the rear axles.
If you are running with one wheel off the ground, then
do not bend that axle. You will obviously have to
account for the slight reduction in height of the
dominant front wheel due to the angle of the axle bend.
For the rear axles,
install the wheels and axles into the rear axle holes
with the mark on the head of the axle at the 12:00
position pointing straight up. The wheels will be
rolling on the inner edge. The car should roll
forwards and backwards with the wheels staying out at
the axle heads. Then, using a pair of pliers and a soft
cloth or thin piece of plastic (piece of plastic bag)
over the axle, rotate the axle left and right until the
wheels stay on the axle head when the car is rolled back
and forth and the rear wheels are running as straight as
possible. Rotating the axle head forward toward
the front of the car body will give you toe in on the
rear axles and rotating the axle toward the rear of the
car body will give you toe out on the rear axles. A
rear wheel with proper alignment for the rail rider is
show below and you can see how the car will ride on the
inner edge of the wheel.
For
the front dominant wheel, insert the wheel and axle into
the axle holes with the mark on the axle head pointing
straight up in the 12:00 position. Then, slightly
rotate the axle until the car moves toward the non
dominant front wheel side such that the car will drift
away from the dominant front wheel. In other
words, if the left front wheel is the dominant wheel,
then the car will drift to the right. If the right
front is the dominant wheel, then the car will drift to
the left. The car should drift approximately 1" to
1 ½" over a 4 foot roll of the car on a flat table.
The following three pictures show a gradual drift of
the car from left to right about 1 ½" over a 4' span of
plastic sheet over a flat table. We use the left front
wheel as the forward dominant wheel and the car drifts
right towards the up wheel and the center guide rail.
Pro Tip:
By cutting a 3/16" strip of business card and placing it
around the axle at the head an additional 0.5 degree of
bend can be achieved. This gives the builder the
options of 1.5°, 2.0°, 2.5° and 3.0° for tuning.
One can view the rail rider technique video which will
help show the technique more visually.
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