Track Roller System of Measurement Metric Shaft Diameter 20 mm Shaft Material Alloy Steel Shaft Material Grade 52100 Shaft Type Concentric Drive Type Hex Socket Drive Location Stud Shaft Thread Size M14 x 2.0 Shaft Thread Length 25 mm Head Diameter 31.75 mm Head Length 16 mm Hex Drive Size 8 mm Overall Length 94 mm Standards AS 9100 ISO 9001