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Step 5: Create the Idle Wheels

Picture of Create the Idle Wheels

Create a set of wheels just like the last step, except this time use a 4.5" (11cm) piece of straw. These wheels can be taped to the other side of the frame since there'll be no rubber band pulling on it (picture 1).

The purpose of these wheels is to reduce friction (versus the frame dragging on the ground) and add some weight to increase momentum. These wheels can also improve how straight the car rolls. Having 4 wheels with rubber bands in contact with the ground helps prevent the car from veering to the side.

Important: The four wheels must be aligned. In other words, the dowels must be parallel to each other. Otherwise the car will veer to the side.