An arcuate support for a disk brake caliper is keyed to a tubular axle casing, for example, by way of a woodruff key, to transmit braking torque. The support may slide axially of the axle casing to permit the caliper to accommodate brake pad wear. This construction eliminates the need for a moving component of the brake caliper itself. In the latter case, braking torque may be transmitted via the keyed connections or via a separate torque arm.