A Closer Look at MacPherson Strut Suspension

Ford

Quick Takes:

• The first vehicle with MacPherson struts was a concept car
• MacPherson struts pair a coil spring and a tubular shock
• Pros and cons of MacPherson struts
• Many cars have MacPherson struts

Your car's suspension is engineered to soak up all the bumps and undulations on the road to keep your car stable and provide a smooth ride. A lot is going on behind your vehicle's wheels to make this happen.

Among the various suspension designs, one of the most common is the MacPherson strut, which has been around since the 1940s.

The First Vehicle With MacPherson Struts Was a Concept Car

After the end of World War II in 1945, General Motors' Chevrolet was investigating the potential of a unibody economy car. Named the Cadet, it never went into production, but the concept's innovative front suspension did. Designed by GM's chief design engineer, Earle MacPherson, the suspension would eventually debut in production form on Ford's 1951 Consul. It eventually became the standard for almost every passenger car and truck.

MacPherson Struts Pair a Coil Spring and a Shock Absorber

MacPherson's eponymous design marries a coil spring with a tubular shock absorber through the center. The strut tower is mounted directly to the vehicle's unibody frame, which acts as the upper anchor point. The lower control arm locates the bottom of the steering knuckle, and the steering link turns the knuckle to turn the wheels.

Because there is no upper control arm, there's more space near the wheel hub compared with a double-wishbone suspension, leaving room for a driveshaft on front- and all-wheel-drive cars.

The Pros and Cons of MacPherson Struts

MacPherson struts require fewer parts than other independent front suspension systems, they're lighter, and they're less expensive to build than many others. The extra lateral space the struts create in the engine bay make space for today's transverse-mounted engines.

The extra vertical space MacPherson struts require, however, makes them taller, resulting in a higher front end on a vehicle. A double-wishbone suspension offers more flexibility for performance and race cars to reduce body roll and improve handling. As MacPherson struts are mounted to the vehicle's frame, unibody construction is necessary to withstand the stress and forces.

Body-on-frame vehicles such as a Jeep Wrangler SUV and Ford F-150 full-size pickup don't have the frame structure for the top of the strut to mount to.

Many Cars Have MacPherson Struts

Because of the many packaging and production cost advantages, MacPherson strut suspensions are found at the front in the majority of new transverse-mounted front-engine unibody vehicles, from front-wheel-drive compact cars such as the Honda Civic and all-wheel-drive SUVs like the Toyota RAV4 to compact crossovers such as the Ford Bronco Sport.

Proving the flexibility in Earle MacPherson's original design, the rear-engine Porsche 911 uses MacPherson struts in the front — except the 911 GT3 — and its smaller, mid-engine 718 Boxster and Cayman siblings use the struts on all four corners.