How do you build a rail riding pinewood derby car?

What do you need?

• Assume the right front wheel is your dominant wheel (the one that will ride against the rail).
• One 1.5 Degree Bent Steering Axle for the right front dominant wheel.
• Two 2.5 Degree Bent Axles to cant the rear wheels.

Prepare the Block

• Cut the right front of the car body back 1/16". This moves the right front wheel, your rail riding dominate wheel, closer to the center guide rail. This insures the right front wheel hits the rail first, keeping the rear wheels away from the rail because you don't want more than one wheel riding the rail.

Steer the Car

• Insert one of our 1.5 Degree Steering Axles into the right front wheel and into the block. Align the screwdriver slot in the axle head vertically, so the steering slot is straight up and down.
• Next, you need to measure the car's drift to steer it for rail riding. You will need a long table or wide board to roll the car on. Put something under the table legs or the board to lift it about 3" to make an incline for rolling your car. Create a "lane" for your car by putting two pieces of masking tape about 6" apart. You will use this lane to see how far your car steers to the left. 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

• Insert 2.5 Degree Bent Axles into the rear wheels. Again, start with the axle slot in the axle head vertical. Turn the bent axles until the rear wheels migrate toward the axle head when you roll the car down your simulated track. This canting reduces friction of the wheel against the car body and moves the rear wheels away from the center rail so only the front wheel is riding the rail.
• 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

• Riding the rail stabilizes the car as it runs down the rail, which allows you to bias the center of gravity further back. So instead of COG being 1.25" in front of the rear axle, you can get away with 1" or even a little less. Moving COG further back converts more potential energy to kinetic energy. Basically, your car goes faster, longer.

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.