Most people think tractor tires are filled only with air, but that’s not always the case. Some farmers deliberately add liquid to the tires to increase their weight. In hot regions, ordinary water is often used. However, in cold areas, water can freeze and damage the tires, so non-freezing liquids—such as windshield washer fluid—are used instead. Typically, the tire is filled to about three-quarters full, with liquid at the bottom and air at the top. This setup provides added weight without nega