Ryobi RY48ZTR75 Manuel D'utilisation page 24

 Loosen the blade nut by turning it counterclockwise (as
viewed from bottom of mower) using a 15 mm wrench
or socket (not provided).
 Remove the blade nut, spring washer, and blade.
 Place the new blade on the shaft against the corresponding
blade posts. Ensure blade is properly seated with shaft
going through center blade hole and the two blade posts
inserted into their respective holes on the blade. Make
sure it is installed with the curved ends pointing up toward
the mower deck and not down toward the ground. When
seated properly, the straight sides should be aligned and
the blade should be flat against the blade posts.
 Replace the spring washer, then thread the blade nut on
the shaft and finger tighten.
 Torque the blade nut down clockwise using a torque
wrench (not provided) to ensure the bolt is properly
tightened. The recommended torque for the blade nut is
600-650 in. lbs.
WARNING:
Ensure blade is properly seated and the blade nut is
tightened to the torque specifications above. Failure to
properly attach the blade could cause it to come loose
and result in possible serious personal injury.
 Repeat with second blade, if needed.
MAINTENANCE
BLADE
CIRCLE HOLE
24 — English
BLADE
CIRCLE
POST
SHAFT
CENTER
BLADE
HOLE
BLADE
NUT
SPRING
WASHER
BLADE HALF
CIRCLE POST
BLADE
HALF
CIRCLE
HOLE
BLADE
Fig. 21