Alfa Romeo 4c alloy wheel bolts 17mm Hex M12 x 1.25, 26mm thread x 20
• Thread size: M12 x 1.25. What is M12 x 1.25?. • Thread length: 26mm. • Spanner size: 17mm Hex. The Hex refers to the size of the nut/bolt head and therefore the corresponding size of the socket used with the wheel brace.