Honda PIONEER SXS1000 2016 Owner's Manual page 188

Brakes
Brake Pad Wear
Refer to Safety Precautions on page 111.
Brake pad wear will depend upon the severity of usage and driving
conditions. The pads will wear faster in wet or muddy conditions.
Inspect the pads during all regular service intervals to determine the
pad wear.
Note that the pads are designed to make a metallic noise during
braking when they reach the wear limit.
If you hear a continuous metallic friction sound when applying the
brakes, the brake pads need to be replaced. Have the vehicle
checked by a dealer.
184
Servicing Your Honda