Double Wishbone Suspension

Double-wishbone suspension is an independent suspension layout that locates each wheel with two roughly triangular control arms, the wishbones, mounted one above the other. It exists to give engineers fine control over how a wheel moves relative to the body, which in turn governs how the tyre meets the road. Because handling, grip and stability depend heavily on keeping the tyre's contact patch correctly oriented through bumps and cornering, the double wishbone has long been the layout of choice where precise dynamics matter, from sports cars to the front of many premium saloons and the corners of competition machinery.

Each wishbone is an A-shaped or Y-shaped arm with two pivot points at the body or subframe and a single ball joint at the wheel hub, or upright. The upper and lower arms work together to define the wheel's path of travel as the suspension compresses and rebounds. A spring and damper, often a coil-over unit, control vertical movement and absorb road inputs. Because the two arms can be made different lengths and set at different angles, designers can shape exactly how the wheel's camber and track change through the suspension's stroke.

The practical payoff is geometric control. By tuning the arms, engineers can keep the tyre close to upright relative to the road even as the body rolls in a corner, preserving the largest possible contact patch and therefore maximum grip. This is the configuration's signature benefit: where a simpler strut allows the outer wheel to lean with the body and lose camber in hard cornering, a well-designed double wishbone counteracts that tendency, delivering sharper turn-in, more stable braking and more consistent behaviour at the limit.

The arrangement has close relatives. The short-long arm, or SLA, suspension is essentially a double wishbone in which the upper arm is deliberately made shorter than the lower one to optimise camber gain, and the term is often used interchangeably in North America. The multi-link suspension can be seen as an evolution that replaces the solid wishbones with several separate links, decoupling the various geometric parameters for even finer tuning, at the price of greater complexity. All of these contrast with the compact, cheaper MacPherson strut, which integrates the damper into the wheel location and uses only a single lower arm.

The main drawbacks are cost, complexity and packaging. A double wishbone uses more components and more pivot bushings and ball joints than a strut, each a potential wear item that can develop play, knocking or imprecise steering with age. It also occupies more space, intruding on the room available for an engine or for a low bonnet line, which is one reason many mainstream front-wheel-drive cars use a strut at the front instead. Where the budget and the layout allow, however, the double wishbone remains a benchmark for ride and handling refinement.