Ducati ST3 Owner's Manual page 157

STANDARD factory setting is as follows:
compression: 12 clicks;
rebound: 11 clicks.
spring preload: 16 mm
Range of adjustment:
compression: 16 clicks;
rebound: 14 clicks.
spring preload (A, fig. 38): 10 - 25 mm
E
To change the preload of the spring inside each fork leg
turn the hex. adjuster (2, fig. 38) with a 22-mm hexagon
wrench.
3
fig. 39
Important
Adjust both fork legs to same settings.
48