How to Build a Soapbox Derby Car

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How to Build a Soapbox Derby Car

Soapbox derbies are a favorite competitive sport among adolescents and teenagers. Many young people spend half of a summer building their own vehicles, and the other half racing the cars along exciting slopes in the neighborhood. If you want to help your child build his or her own soapbox derby car, here are some tips to help you out.


A soapbox derby car is essentially a motor-less wagon with its own steering and braking system. The basic design of a soapbox derby car involves the following components:

  • The chassis is the frame of the vehicle, and holds all of the parts of the vehicle together.
  • The drivetrain makes up the wheels, steering system, and brakes of the vehicle.
  • The body of the car keeps the vehicle enclosed and safe.

Blueprints for a soapbox derby car can be downloaded from the Internet. Try to find something very detailed, but you should be able to understand the numbers and calculations written on them.

Building the Car

To build a soapbox derby car, follow these steps:


    soapbox derby

  1. The simplest chassis and drivetrain system you can use for a simple soapbox derby car is a pull wagon.
  2. Unless specified by the blueprint, it’s best to use lightweight metal pipe. Composite and carbon fiber can be expensive, and the extra weight added by plumbing pipes can severely affect the speed of your soapbox derby car.
  3. Build the frame according to the specifications and instructions in the blueprint.
  4. Always check your welding points. The weld is the weakest part of any assembly of metal, so you should make sure that the chassis can withstand high speeds, and the weight of the driver.


  1. Assemble the wheel and axle system as described in the blueprint.
  2. To achieve stability, assemble torsion trusses connecting both axles to the steering column for a four-wheel drive soapbox derby car. For maximum maneuverability, connect the front axle to the steering column.
  3. Install the brakes on the wheels as specified by the instructions on the blueprint. The brake assembly should be connected to the brake pedal.
  4. Do not forget to include a racing seatbelt (5-point harness belt) on the vehicle.


  1. Reinforce the shell of the soapbox derby car with trusses. The car will bump other vehicles at the track or course, so you need to make sure the driver is safe.
  2. Take the time to construct a rollcage that extends to the body of the chassis. The rollcage helps to keep the driver safe in the event that his or her car rolls over during the race.
  3. Paint the body with colors, decorate it with images, or cover it with decals that your child likes.

That slope in your neighborhood will turn into a soapbox derby track in the summertime. With these tips, you can help your child enjoy summertime right behind the wheel of his or her own soapbox derby car.



  1. Me said,

    on March 26th, 2012 at 1:26 am

    This is a great article

  2. raegan jones said,

    on March 17th, 2012 at 3:16 pm

    This post was not helpful at all. This information is available through common sense and about a zillion other sites. When I searched for soap box car blue prints this post came up. What a waist of time!!