Honda Pioneer SXS700M2P 2019 Owner's Manual page 188

Tyres
Also, if you hit a hard object while driving, stop as soon as you safely
can and carefully inspect the tyres for damage.
Tread Wear
To check the condition of a tyre tread, measure the groove depth in
the centre of the tyre.
For best performance, you should replace a tyre before the tread
depth at the centre reaches the following limits:
front
rear
178 Servicing Your Honda
4 mm (0.16 in)
4 mm (0.16 in)
groove depth
4 mm (0.16 in)