Art of “Rail
By Jay Wiles
Copyright: Derby Worx / Warp Speed Inc. 2008
the start of the Pinewood Derby® in 1953 both common sense
and the laws of physics have told us that to get the fastest car
possible you need to get the car to go perfectly straight without
ever touching the center guide strip. This would be the fastest
way possible if we lived in a perfect world. Unfortunately we don’t,
and even if a “perfectly aligned” car could be achieved,
and ran on a “perfectly level” track it would take
a very small misalignment (a couple thousands of an inch) in staging
to cause this “perfect car” to hit the guide strip.
Not only will this “perfect car” hit the guide strip,
it will do it numerous times during the course of the run, each
time losing precious energy and fractions of a second.
laws of physics tell us that for every action, there is an equal
and opposite reaction. As this “Perfectly aligned” car
hits the center strip these laws cause it to change direction thus
causing it to hit the guide rail on the other side. This back and
forth motion will usually continue through out the run causing
numerous impacts with the center strip.
impacts cause a braking effect where, just like tapping the brakes
in your car, it slows the Pinewood Derby® car as well. Not
only does this eat up precious energy we could use to propel the
car towards the finish line, it causes the car to go into a back
and forth motion bouncing from side to side off of the guide strip.
This effectively lengthens the traveled path of the car thus making
the track seem longer than it is. The longer the traveled path,
the more time it takes to travel this distance. This is the problem
Pinewood Derby® racers have been trying to overcome for the
past 55 years!
I started helping my son with his first Pinewood Derby® in
2001 I did as most in the modern era have done and turned to the
internet for as much information as I could get on the techniques
of making a fast car. I studied every web-site, article and forum
I could find. Bought numerous web books and we studied them all.
We did well our first year coming in 2nd in Pack and 8th in District
races. We had so much fun researching information and building
the car we started right away on next years car.
purchased a test track, made several cars and started testing all
the basic theories. It was during this testing that we found “Rail
Riding!” We noticed that we could build identical cars, put
the same wheels and axles on them, align them to go perfectly straight
but there would be a huge difference in time between them. The
fastest cars were always the most steady (no side to side oscillation)
but some were markedly faster than others. Set on getting to get
to the bottom of this I started watching the cars from the finish
end of the track, and from behind the track at the starting gate.
I noticed the fastest cars didn’t go straight, but went to
the center rail with the dominant front wheel (the one touching
the track on a 3 wheeler, or the one carrying the most weight in
a four wheel touching configuration) soon after the start gate
dropped. The slower cars always did this with the non-dominant
front (raised wheel) and would either oscillate back and forth,
or stay there and run really slow, sometimes even making a “squealing” noise.
began the “Rail Riding” era in Pinewood Derby® racing.
more testing we found “Rail Riding” was by far the
fastest way to set-up a car, and could be easily duplicated from
one car to the next. This set-up allowed my son to go undefeated
for the next 4 years in Cub Scouts (from pack through state races)
and helped to win the “WIRL National Stock class Championship” and
overall “Builder of the Year” in 2005.
is how “Rail Riding/Rail Hugging” was invented, and
we believe it is the single biggest change to Pinewood Derby® since
the start of it 55 years ago!!!
short description follows on how to set one up along with a couple
of tips on making it effective.
The Rail-Riding Method
method makes for a straight, fast, easy to align car, especially
for those without a test track.
drill the body with our Pro Body Tool,
straighten your axles with a Pro Axle
Press and polish them. Mark
the axle @ .350" from
the head and put a dot at 12:00 on head with a sharpie.
install the axle into our Pro Axle Press at
the .350" mark
with the dot on the head down and slightly bend the axle with a
light hammer tap. Another way to achieve this is to mount a spare
wheel (one not going to be used in competition) on the axle before
inserting it in the Pro Axle press (wheel against axle head) and
gently push up on this wheel to achieve the required bend. I use
a digital caliper to measure from the head of the axle to the work
bench to verify my bend. On the rear axles we like to start with
a .020" bend and .014" on the front axle. You can
use our Rail Rider tool to accurately
bend the axles
install the rear axles with the dot up at 12:00 as well as the
front axle (dominant wheel).
car should roll forward and backwards with the rear wheels staying
on the axle heads. If not, rotate the rear axles slightly fore
and aft until both are perfect and do not migrate. Use slight rotation
fore or aft of the front axle (dominant side) to steer the car
into the rail. The amount of “steer” or “drift” needed
will vary from track to track and with different set-up (weight
placement, condition of wheels etc.) but 2" drift towards
the non-dominant (raised) front wheel over a 4' test roll will
give you a good starting point that should be fairly competitive
at most levels of racing.
is also recommended that the front “dominant” side
of car be narrowed 1/16 of an inch in relation to the same side
rear wheel. This slight “offset” of the front wheel
will ensure that with proper rear alignment, the rear wheel never
touches the guide rail. For a fast car, only the dominant front
wheel makes contact with the guide rail. If the rear wheel touches
the guide rail, it will increase energy loss and drag thus resulting
in slower times during car races.
are the basics of setting up a fast “Rail Riding” Pinewood
Derby® car and are a great starting point for any level of
racer. For more information, watch
We sell a tool that makes
this method make your Pinewood Derby® experience fun and successful!
Good Luck and Happy Racing!