Ducati Multistrada 1000DS 2004 Owner's Manual page 76

Minimum tread depth
Measure tread depth (S, fig. 70) at the point where tread
is most worn. It should not be less than 2 mm and anyway
not below the legal limit.
S
Important
Visually inspect the tyres at regular intervals for
cracks and cuts, especially on the side walls, bulges or
large spots that are indicative of internal damage. Replace
them if badly damaged.
Remove any stones or other foreign bodies caught in the
E
tread.
fig. 70
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76