Track Roller System of Measurement Inch Shaft Diameter 1 1/4 in Shaft Material Alloy Steel Shaft Material Grade 52100 Shaft Type Concentric Drive Type Hex Socket Drive Location Stud Shaft Thread Size 1 1/4 In.-12 Shaft Thread Length 1 5/16 in Head Diameter 2 1/4 in Head Length 7/8 in Hex Drive Size 1/2 in Overall Length 5 1/4 in Standards AS 9100 ISO 9001