Control Blade rear axle · Focus Mk3, opened up

The Control Blade: a steel trailing arm that is stiff fore and aft but flexes sidewaysSpring link (long, carries the spring) · toe link (short, ahead) · camber link (upper)Damper mounted apart from the springThe Focus rear axle is four links and a blade. The blade, a long pressed-steel trailing arm welded to the knuckle, holds the wheel fore and aft and takes the brake torque; three lateral links do the rest: the long lower link carries the coil spring, the short toe link ahead of it steers the wheel a fraction, and the upper camber link sets the tilt. Because the toe link is shorter, it swings through a tighter arc, so as the wheel rises the front of the tyre is pulled in a little: toe-in in bump, which keeps the rear stable in corners. The blade can bend sideways just enough to allow it. Camber and toe in the readout are computed from this figure's own link geometry (tuned to behave like the real axle), not taken from Ford's specifications.

Interactive figures of a Ford Focus Mk3 sedan (C346, 1.6 Ti-VCT, PowerShift automatic). Drawn with the MIT-licensed anatomy isometric kit. Not affiliated with Ford.