Mazda RX-8 Workshop Manual page 1366

CAUTION:
Set the bead breaker at the position laterally opposed to the valve.
Do not break the bead loose within the range of 300 mm {11.8 in} on each side of the
valve. Otherwise, the wheel unit could be damaged.
4. Insert the tire lever at the point 40 mm {1.6 in} from the wheel unit in the direction that the tire
changer turntable rotates.
5. Remove the bead from the wheel.
NOTE:
Using the tire lever as a support will aid in preventing the tire changer arm from
deviating from the point at which the bead is first broken.