Abstract: Disk brakes are located to the interior of the outermost extent of the space frame of the wheelchair, and are within the volume of this space frame, being most commonly under the seat of the occupant of the wheelchair. In this location the disk brakes are subject to unobstructed operation, and will in particular not be subject to detrimentally contacting the garments or covers of an occupant of the wheelchair. The disk brakes are preferably hydraulically actuated, and stabilized by a strut connecting two bearing blocks through each of which passes an associated axle shaft connecting to the hub of an associated wheelchair wheel at an outboard location, and also to a an associated disk brake rotor at an inboard location.