Q: What Is a Strut?

A strut, also known as a MacPherson strut, named after Earle MacPherson, the engineer who developed this type of suspension, looks like a big tube-style shock absorber and uses the upper part of the strut as a steering pivot, instead of an upper control arm. The bottom of the strut meets the outer end of the lower control arm, and it’s at this point that the part that supports the wheel, known as the steering knuckle or wheel carrier is mounted. Typically, the coil suspension spring is combined concentrically with the tube of the strut, or a strut can also be used with torsion bars as the suspension medium. Eliminating the upper control arm is more space efficient and allows for fewer parts in suspension systems, lowering manufacturing costs. Strut type suspension systems are in wide use by many manufacturers. If you notice the symptoms of a bad or failing strut, book a strut assembly replacement with an ASE-certified mechanic from YourMechanic.