Ducati Scrambler Owner's Manual page 170

Measure tread depth (S, Fig 123) at the point where
tread is most worn down: It should not be less than
0.08 in (2 mm), and in any case not less than the legal
limit.
Important
Visually inspect the tires at regular intervals for
cracks and cuts, especially on sidewalls, bulges or
large spots which are indicative of internal damage.
Replace them if badly damaged. Remove any stones
or other foreign bodies caught in the tread.
168
S
Fig 123