You may have noticed the small weights placed on the rim of your tyre. These weights help the tire remain balanced at all speeds. At high speeds a tyre which is not balanced properly can generate severe vibrations. An unbalanced tyre and wheel can also lead to irregular treadwear.
Some expensive alloy wheels can be damaged with the use of standard lead weights and may require the use of a coated weight. See your Toyo dealer for more information.