How to Build a Soapbox Derby Car

Soapbox derby cars are downhill single person racers made of wood and various 'found' materials. Through the years these cars have evolved from simple plank and axle machines into advanced constructions with shaped car bodies and advanced steering controls. But at the heart of even the most advanced soapbox racers is a basic design that you can build onto, creating the design that best fits your manner of racing.

Things You'll Need

• Wood planks
• Wood saw
• Hammer
• Nails
• Axle bars
• Drill
• Pivot bolt
• Rope
• Driver's seat
• Screwdriver
• Screws
• 4 wheels

Instructions

1. Cut the chassis plank to the length you desire for your car. Shorter lengths mean tighter turns but at the cost of handling stability. Typical length is between four and five feet long, with width and thickness of the plank largely determined by the size and weight of the driver.

2. Connect the axle bars to the axle planks. The length of the axle planks also determine stability, with longer planks leading to a more stable car.

3. Nail the rear axle plank to the rear of the chassis plank centered beneath the plank.

4. Drill a hole in the center of the front of the chassis plank above the center of where the front axle plank will be attached. Drill a co-responding hole in the front axle plank. Place a pivot bolt through the two planks with a washer between the planks to reduce friction. Secure the bolt tightly into place.

5. Drill two holes through the front axle plank, one on each side of the chassis plank at the far ends of the axle plank, to run the steering rope through. Attach the rope, running it through the holes and securing it tightly into place with enough run in the rope to reach the driver's location.

6. Add the seat to the chassis plank for the driver, placed over the rear axle plank, and screwed securely into place. To provide a stable perch for the seat, cut and place two offset blocks to the top of the rear axle plank.

7. Secure the wheels onto the axles, aligning the rear wheels with the front wheels.

8. Add any decorative elements you wish to the vehicle, including a car body.

Tips & Warnings

• You can purchase a soapbox derby racer kit that can be used to create advanced derby cars suitable for competition racing.

• Always wear a helmet when driving your soapbox derby car, and avoid riding in streets that are in use.

• In order to participate in organized racing, you will need to build a car based on the racing league's specifications.

References

• Derby Tech Magazine

Resources

• All-American Soap Box Derby
• Salem Soap Box Derby