Track Roller System of Measurement Metric Shaft Diameter 45 mm Shaft Material Alloy Steel Shaft Material Grade 52100 Shaft Type Concentric Drive Type Hex Socket Drive Location Stud Shaft Thread Size M45 x 4.5 Shaft Thread Length 54 mm Head Diameter 82.6 mm Head Length 32 mm Hex Drive Size 12.2 mm Overall Length 185 mm Standards AS 9100 ISO 9001