Mazda 2009 MX-5 Miata Owner's Manual page 361

Maintenance and Care
Owner Maintenance
When replacing a wheel, make sure the
new one is the same as the original factory
wheel in diameter, rim width, and offset.
Proper tire balancing provides the best
riding comfort and helps reduce tread
wear. Out-of-balance tires can cause
vibration and uneven wear, such as
cupping and flat spots.
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