MacPherson strut suspensions are all well and good, but what if you want something a little… sportier?
As the name would imply, the setup implements two wishbone-shaped control arms of different length, one upper and one lower. They both hold the spring and damper in place, and as the two are compressed, the control arms adjust the wheel’s camber(the vertical angle at which the wheel is positioned) in order to create a larger contact area and thus provide more grip. In order to achieve this sort of effect with a MacPherson strut setup, the suspension as a whole would have to be stiffened, compromising the ride.
As a general rule, double wishbones are more complex, adjustable, and more performance-oriented, hence why they’re used in racecars and sports/supercars(like the Audi R8 pictured above) in addition to body-on-frame trucks and SUVs like the Ford F-150. Suspension characteristics such as the aforementioned camber, caster, and toe can all be meticulously tuned and adjusted to perfect the handling of a car and maximize its speed through a corner. Another advantage of this form of setup is the lack of vertical space needed to fit such a mechanism within a car. Cars like the Audi R8 are very low to the ground and aren’t very tall(necessary for improved cornering), and so, in order to be able to actually fit a suspension system while maintaining that height, such a system is needed.
However, as with anything, the double-wishbone suspension design has its drawbacks. For one, the extra parts used in this setup make the cost of implementing it much greater, particularly when compared to the MacPherson strut system which I covered the other day. In addition, it is a fair bit heavier and far more difficult to repair due to those same extra parts. Furthermore, the double-wishbone requires more horizontal space to fit in a car and is difficult to use in front-wheel-drive cars as a result of that. Nonetheless, this useful technology has multiple applications in the area of automotive performance and will undoubtedly continue to do so for years to come.
Author at STEMTalksNC