Track Roller System of Measurement Metric Shaft Diameter 55 mm Shaft Material Alloy Steel Shaft Material Grade 52100 Shaft Type Concentric Drive Type Hex Socket Drive Location Stud Shaft Thread Size M52 x 5 Shaft Thread Length 62 mm Head Diameter 88.9 mm Head Length 32 mm Hex Drive Size 12.2 mm Overall Length 195 mm Standards AS 9100 ISO 9001