Abstract: A disc brake provides an adjustment mechanism to dispose a pair of friction elements in close proximity to a rotor by limiting the amount of retraction of the friction elements from the rotor. The adjustment mechanism has more than one rate of extension so that large clearances between the rotor and friction elements are reduced to a predetermined running clearance with few brake applications. In particular, a pawl engages a toothed member upon a brake application to rotate the toothed member, thereby extending an extensible member which limits retraction of the friction elements to a predetermined running clearance after a brake application. Keys on the pawl are engageable with the toothed member. These keys are radially disposed to each other so that different rates of rotation are provided for the toothed member thereby varying the rate of the extension of the extensible member.