An Upright is the structural member at each corner that carries the wheel bearing and brake, and connects the wheel assembly to the suspension links and steering. On a front short-long arm suspension it is also called the spindle or knuckle and it picks up the upper and lower ball joints plus the steering arm; on a MacPherson strut car the upright is instead clamped to the base of the strut. The upright’s dimensions set the steering axis inclination, the scrub radius, the caster and the spindle height, so its geometry defines much of what the suspension can do. Because it carries cornering, braking and impact loads in bending, upright stiffness and strength directly affect camber and toe accuracy under load.