mousetrap cars and vehicles

Wheel Traction and Friction

By Doc Fizzix // Published Nov 17, 2005

Friction is not always a bad thing. Without friction you could not move anywhere. As you walk forward, it is the friction on the bottom of your feet that allows for the grip you need to move. It is the friction between the road and your tires that keeps the wheels from slipping and allows your vehicle to move. This type of friction is called traction and is a desired form of friction.

What type of wheels work best: fat tires, thin tires, knobby tires, or smooth tires? Knobby tires have good traction if the road surface is rough, but the trade off is that they are inefficient and use more energy than smooth wheels. When pressure is placed directly on a knob, more force compresses the tire causing the rubber and air inside the tire to heat up. The energy it takes to compress the rubber and air in the tire is lost as heat. Knobby tires become hotter with continued use.

Race cars use smooth tires called slicks. Smooth wheels will be more energy efficient and allow a car to travel faster. On mouse-trap cars, smooth tires will allow a vehicle to travel a longer distance. The amount of grip your tires have on the floor not only depends on whether you have knobby tires or slicks but also depends on the material your tires are made from and the force pushing the tires to the floor. Different compounds of materials will have different amounts of grip. For instance, rubber bands wrapped around a wooden wheel will provide better grip during acceleration than the wood of the wheel will alone. You should select or design tires to provide maximum traction or grip on the floor. Tires with little grip on the floor will have a tendency to slip when under a load, thereby decreasing your car's maximum acceleration or distance. You can also increase the traction by adding a non-slipping gel like Traction Action, a sticky gel that is smeared on the wheels. Experiment with different materials in order to find the best traction.

WARNING! This should tip should only be used on vehicles that require a lot of pulling torque (speed-trap racer, power-pull, hill-climb), this should not be used with distance racer! DO NOT TRY WITH DVD LAYERS

One way to increase a wheels traction is to place a rubber band around it, but in some cases you may not have a rubber band that is large enough to fit around a larger wheel like a compact disc. Here is a way you can add traction to larger diameter wheels; first, take a balloon and cut out the middle section of the balloon, next stretch the middle section of the balloon around the wheel. It is that easy!



See the following related articles to get started:

• basic mousetrap vehicle propulsions (how to make it move)
• making a good distance traveler
• making a good speed-trap racer