Metric Wheel Nuts and Bolts Description
Metric wheel nuts and bolts are identified in the following way:^ The wheel nut has the word Metric stamped on the face.
^ The letter M is stamped on the end of the wheel bolt.
The thread sizes of metric wheel nuts and bolts are indicated by the following example: M14 x 1.5.
^ M = Metric
^ 14 = Diameter in millimeters
^ 1.5 = Millimeters per thread (gap between)