Hitachi ZW 120-6 Operator's Manual page 304

Tire Rotation
Rotate tires when uneven or abnormal wear is recognized
on either front or rear, or right and left tire. Tire rotation is
recommended to achieve uniformity of wear on tires or
equalization of tire service life.
Rotation Procedure
d
WARNING: Install a tire with no external damage such
as score and abnormal wear.
Failure to do so may cause the puncture or the tire to
blowout, possibly resulting in personal injury or death
since tire load is increased when the machine is loaded
or braked during operation.
 Switch tires only between the front and rear positions. Do
not switch the tires between diagonal positions.
 Align the tire rotation direction with the tire tread design
pattern. Especially traction tread design pattern (optional)
will affect not only economy of tire but also safety of
operation.
How to Check Wear Amount (Tread Design Groove
Depth):
Measure the groove depth at 1/4 tread width position
[shown with  mark (1) in the figure].
Use limit of the groove depth shall be approx. 85 % of the
new tire groove depth. In case extreme uneven wear or
exposed rubbing strips are found, replace the tire even
before reaching 85 %.
IMPORTANT: If the machine is operated with such tires at
either rear or front being extremely worn or different
in type, construction, or size, the travel driving system
such as axles or transmission will be adversely affected
in their performance and/or endurance.
When replacing tires, be sure to use the same tires
in type, construction and size to the four wheels. It is
recommended to replace tires of the four wheels at the
same time.
MAINTENANCE
Tread width
7-86
(Right) (Wrong)
Front
Groove
depth
Tread width
M4GB-07-104
1
MNEC-07-122