What Is Double-Wishbone Suspension?
With two articulating arms and six pivot points, double-wishbone suspension allows engineers to tweak how your vehicle moves.
Mazda
Imagine you're driving around a left-hand curve. As you turn, your car's body leans to the right, compressing the suspension on the right side of the vehicle and extending it on the left. In most cars, the suspension doesn't just move the wheels up and down — it also adds vertical tilt, or camber, as the wheels move relative to the body. Controlling camber can dramatically improve a car's cornering traction.
A double-wishbone suspension does this better than most conventional setups, and it's often found on purpose-built race cars and high-performance sports cars, where cornering speed is a top priority.
A Double Wishbone Suspension Offers Precise Wheel Camber Control
A double-wishbone suspension resembles an articulated desk lamp. With two arms holding the lamp head, the bulb stays aimed in one direction no matter how high or low you adjust it. Double-wishbone suspension uses two pivoting arms stacked on each other to connect the wheel to the car's chassis. These arms are called wishbones because of their three-pointed shape, with two hinged points connected to the chassis and the third fastened to the hub that holds the wheel. Suspension wishbones are also known as A-arms or control arms.
With double wishbones, engineers can more precisely control the wheel's camber at any point in the suspension's travel. In a curve, a little bit of tilt can be beneficial: On the wheel on the outside, tilting the top slightly inward (negative camber) helps push the tire more firmly against the ground, improving traction, while on the inside wheel, a slight angle in the opposite direction can improve grip.
With two articulating arms and multiple pivot points, double-wishbone suspension allows engineers to tweak how the suspension moves, optimizing camber for maximum traction in corners.
Vehicles can use a double-wishbone suspension on each front wheel, each rear wheel, or all four wheels. Double-wishbone setups are a form of independent suspension. Unlike a solid-axle solution, a double-wishbone system allows the wheels on each side to move up and down separately in response to road conditions, resulting in a smoother, more controllable ride.
Double-Wishbone Suspensions Are Relatively Uncommon
Many cars don't use double wishbones. They have a simpler strut suspension design with a single pivoting arm. This setup allows the camber to change dramatically as the suspension moves, which takes away some traction in extreme high-speed cornering. The compromise comes down to cost and space.
Double-wishbone suspensions have many precision moving parts, making them expensive to build and maintain. While double-wishbone setups usually require less height than strut suspensions, the A-arms and other components need horizontal space.
In most mainstream vehicles, passenger and cargo space is more important than cornering grip at high speeds. An average driver in an everyday family vehicle isn't competing for lap times, meaning double-wishbone suspension is unnecessary in most conventional vehicles.
Double-Wishbone Suspensions Are Often Used in Sports Cars
Formula 1 race cars use double-wishbone suspension at all four wheels because cornering speed helps win races. Many supercars from Ferrari, Lamborghini, and McLaren use double-wishbone suspension on the front wheels and a similar setup called a multilink suspension on the rear.
Today's Corvette sports car uses double wishbones at all four wheels. Most models of the current Porsche 911 use a more mainstream strut suspension design, but the top-dog $186,000 911 GT3 uses double wishbones at the front. At the other end of the price spectrum, the $29,000 Mazda MX-5 Miata has a double-wishbone front suspension — a rarity among cars at that price but an indicator that Mazda prioritized curvy-road performance for its signature enthusiast model.
