Properly balanced wheels have long been recognized to help provide improved ride quality, better gas mileage and reduced tire wear, making wheel balancing an important part of car care and maintenance.
For decades wheel weights have largely consisted of chunks of lead clamped to the wheel rim. Lead has traditionally been used to make wheel weights because it is cheap and heavy, allowing the use of relatively small weights to balance wheels. However, the highly toxic metal can cause brain damage and other nervous-system disorders in people.