McPherson Struts and Strut Damper

Toyota MacPherson strut front suspension

Honda CR-Z Front MacPherson Strut suspension.

The McPherson Struts is a further development of double wishbone suspension. The upper
transverse links is replaced by a pivot point on the wheel house panel, which takes the end of
the piston rod and the coil spring.

Advantage :

The McPherson Strut is that all the parts providing the suspension and wheel control can be combined into one assembly.

Disadvantage :

Less favorable kinematic characteristics, introduction of forces and vibrations into the inner
wheel house, and it is more difficult to insulate the road noise.


The friction between the piston rod and guide impairs the springing effect, it can be reduced by
shortening distance b.

Rear view of left hand side of the McPherson front axle on the Opel with negative kingpin offset
at ground (scrub radius) and pendulum-linked anti-roll bar.

The coil spring is offset from the McPherson strut to decrease friction between piston rod 2
and the rod guide. Part 2 and the upper spring seat 9 are fixed to the inner wheel house panel
via the decoupled strut mount 10.

The additional elastomer spring 11 is joined to seat 9 from the inside, and on the underside
it carries the dust bolt 12, which contacts the spring seat 3 and protects the chrome-plated
piston rod 2. When the wheel bottoms out, the elastomer spring rests on the cap of the
supporting tube 1. Brackets 4 and 13 are welded to part 1, on which the upper ball joint of the
anti-roll bar rod 5 is fastened from inside. Brackets 13 takes the steering knuckle in between
the U-shaped side arms.

The upper hole of the bracket 13 has been designed as an elongated hole so that the camber
can be set precisely at the factory. A second-generation double-row angular (contact)
ball bearing 14 controls the wheel.

The ball pivot of the guiding joint G is joined to the steering knuckle by means of clamping
forces. The transverse screw 15 grips into a ring groove of the joint bolt and prevents it from
sliding out in the event of the screw loosing.

The sub-frame 6 is fixed to the body. In addition to the transverse control arms, it also takes the
engine mount 8 and the back of the anti-roll bar 7. The drop center rim is asymmetrical
to allow negative wheel offset at ground.

McPherson strut mount on the VW Golf III with a thrust ball bearing, which permits the rotary
movement of the McPherson strut whereas the the rubber anchorage improves the noise
insulation.

Initially the deflection curve remains linear and then becomes high progressive in the main work
area, which is between 3kN and 4kN.

In the car final assembly line the complete strut mount is pressed into the conical sheet metal
insert on the wheel house inside panel 1. The rubber layer 2 on the outside of the bearing
ensures a firm seat and the edge 3 gives the necessary hold in the vertical direction.
The rubber ring 5 clamped on plate 4 operates when the wheel rebounds fully and so provides
the necessary security.

The McPherson strut rear axle on the Lancia Delta with equal length transverse links of profiled
steel trunnion-mounted close to the center the cross-members 7 and 8. As large a distance as
possible is needed between points 6 and 14 on the wheel hub carrier to ensure impaired
straight running.

The fixing points 13 of the longitudinal links 16 are behind the wheel center, exactly like
mounting points 17 of the anti-roll bar 18. The back of the anti-roll bar is flexibly joined to the
body via tabs19. The additional springs 10 attached to the top of the McPherson struts are
covered by the dust tube 20. The cross-member 15 helps to fix the assembly to the body.
An important criterion for dimensioning the control arm 16 is reverse drive against an obstruction.

BMW E30 McPherson strut front suspension.