Buying Guide · Sized by Spindle

Spindle hardware is sized by spindle diameter

Castle nuts, washers, tang washers and cotter pins all key off the spindle's threaded end — 1"-14 is the common 3.5K size. Measure the threaded diameter or read your old castle nut. The axle anatomy guide shows every piece in order of assembly (washer → castle nut → cotter pin → cap).

📱 Not sure what you have? Text a photo to 517-225-1991 — greasy, worn, no label, doesn't matter. We match parts from photos all day.