Studded bike tires on concreate.

Whether you’re a road cyclist, mountain biker, or triathlete, if you spend time on two wheels you will inevitably crash.

This is what can happen when you ride on concrete surface on spikes. Your front wheel slides like on ice. Fortunately the rider was not hurt, only minor scratches on knee.

See also Studded bike tires on concreate. Vol. II

Remember be careful out there.