How to Make a Rail Riding Pinewood Derby Car
Why would you want to make a rail rider (also known as rail runner) car?
The assumption is that when a car races down a track that has a center guide rail (some don't!) the car's wheels will inevitably hit the center guide rail. When it hits the rail, the car loses speed due to friction against the rail and drag on the wheel's rotation.
This is not good.
Even cars that "steer straight" could hit the rail once or twice as it speeds down the track. Rail Riding, if done correctly, addresses this "Rail Banging" by guiding the car gently into the rail, making it ride the rail all the way down the track. It sounds counter intuitive but the idea is that you are trading off constant friction on the one wheel that is riding the rail for potentially multiple speed losing bangs on all four wheels.
But be careful! Rail riding is not the "be all, end all" for creating the fastest car. There are dangers! I don't recommend it for everyone. See important reasons to NOT make a rail rider at the end of this section.
How do you build a rail riding pinewood derby car?
What do you need?
Prepare the Block
Steer the Car
Now, place the car on your incline in the center of the two pieces of tape and release it so it rolls. Observe the cars drift. Adjust the steering axle left or right so the car drifts gently to the left no more than 1" over 4' (or about 2" over 8' if you have a longer "track"). Your car is now configured to drift into the rail.
….but you are not done!
Cant the Rear Axles
When your car is adjusted properly, glue the axles in place with a good epoxy so they don't get knocked out of alignment during the race.
Added advantage of Rail Riding
IMPORTANT! DON'T Make a Rail Riding Car if…
Bottom line: Rail Riding works if the car is adjusted properly and your track sections match perfectly when it is assembled. If you don't have a test track, I suggest running the car dead on straight. If you have a test track, or access to one, run your car as a rail rider several times, then run it straight several times. Use whichever is fastest.
Do you need to raise a front wheel to make a rail rider?
No. Raising a front wheel is another proven speed advantage (see Triple Threat in my Winning Pinewood Derby Secrets book) but is not required for rail riding.
Rail Rider is a registered trademark of Warp Speed Derby, Inc.
Tips & Hints
If you have a bad wheel and you don't have time to replace it, Raise that Wheel so it doesn't touch the track. Since it doesn't touch the track, it won't have any negative affect on your car's speed.
Nyoil stays on your axles throughout the race, unlike powdered graphite that blows off every time your car goes down the track. This gives Nyoil coated axles a speed advantage if your car keeps racing.
If your block is cracked, don't panic! The only problem with a cracked block is if the crack is near the axle, which can cause the axle to move. Random cracks in safe areas can simply be filled with wood filler.
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