Vintage BMX crowns are generally made of aluminium or chromed steel, with a central hole of 23.8 mm for one-piece cranks and 22 mm for 3-piece axles. They are fitted either directly to the crank or via a spider with a 110mm or 130mm BCD. The number of teeth varies between 36 and 48, depending on use (freestyle, race or cruising). Iconic brands such as Redline, Hutch, Haro and GT have left their mark with iconic designs.