The mechanical advantages of wheels and axles differ from one vehicle to the next due to the fact that wheels and axles come in varying sizes. To determine individual mechanical advantages, the radius of the wheel must be divided by the radius of the axle.
Mechanical advantage is the ratio between the force that is put into a mechanism and the force the mechanism delivers. The larger this ratio is, the larger the force. It is fairly simple to create a larger ratio on a wheel and axle by simply increasing the radius of the wheel or axle. This can be accomplished by replacing the existing wheel or axle with a similar one of a larger size.
The wheel and axle has a history that dates back thousands of years. The oldest wooden wheel and axle ever found was discovered in Slovenia and is estimated to be at least 5,000 years old. The wheel has a radius of 70 cm and was crafted of ash and oak, while the axle, made of oak, is 120 cm long. The oldest depiction of a wheeled vehicle was painted on a vase that was discovered in Poland and is estimated to be from at least 3635 B.C.