MacPherson strut

The MacPherson strut is a type of automotive suspension system that uses the top of a telescopic damper as the upper steering pivot.

The line from the top mount of the strut to the bottom ball joint on the control arm gives the steering axis inclination.

Notable examples include the Honda Accord and Civic, as well as the Mercedes E-Class, all of which adopted struts to improve crash performance[citation needed].

The overall simplicity of the design also means there are fewer joints in the suspension to wear, so there is less decline in handling and steering feel over time[citation needed].

Inverted monotube struts can also provide extra rigidity in the front suspension, as seen in the Porsche 911 GT3 and Cayman GT4, as well as the Subaru Impreza WRX STI.

It is not generally considered to give as good handling as a double wishbone or multi-link suspension, because it allows the engineers less freedom to choose camber change and roll center.

Cars that have cockpit adjustable ride height generally cannot have MacPherson struts because of the camber changes that are an unavoidable part of the design.

Ride suffers because the shock absorber has almost the same vertical motion as the wheel, so there is relatively little leverage to break the stiction in the seals.

Despite the drawbacks, the MacPherson strut set-up is still used on some high performance cars, because they tend to have relatively small suspension travel, and so do not have the same kinematic problems.

Up until the 1989 model year (964), Porsche 911 used a similar strut design that did not have coil springs, using torsion bar suspension instead.