There is disclosed a disc brake system incorporating a split caliper having a first caliper half integrally formed with a mounting plate for mounting the caliper on a vehicle. A second caliper half is fixedly and removably attached to the first caliper half in spaced apart relation to provide room for a rotor to be disposed between the caliper halves. The joiner plates permit adjustment of the distance between the caliper halves to accommodate rotors of different thickness. The split design provides a slimmer caliper profile permitting the use of larger diameter rotors in the same space. A splined rotor carrier permits mounting of the rotor on to a wheel hub housing having a corresponding spline. The disc brake system of the present invention is particularly useful in retrofitting existing vehicles, especially light armored vehicles (LAV's).