Wheel weight — Wheel weights are used to balance the tires. Wheel weights are made of soft lead and come in different sizes depending on the amount of weight the tire needs to balance. A computerized wheel balancer can determine where the weights need to be placed on the wheel and how much weight is needed.
Just a small mount of weight can make a huge difference in ride performance. A tire that is out of balance will shimmy and vibrate and this vibration can be felt inside the car and in the steering wheel. If a vibration is felt at one speed but not at another it is probably due to an out of balance problem.