MacPherson Strut
A common independent suspension design that integrates a coil spring and shock absorber into one structural load-bearing assembly.
The MacPherson Strut is the most popular front suspension design used in modern passenger cars and SUVs. Developed by engineer Earle S. MacPherson, it combines a coil spring, a damper (shock absorber), and an upper steering pivot into a single, vertical structural assembly.
Unlike a traditional shock absorber, which only dampens chassis bounce, a MacPherson strut is a load-bearing suspension member that supports the weight of the vehicle and keeps the wheel in alignment. The bottom of the strut bolts to the steering knuckle, while the top bolts to a reinforced strut tower in the vehicle's body.
This design is highly valued by manufacturers because it is compact, lightweight, cost-effective, and leaves more room in the engine bay for front-wheel-drive layouts. However, because it acts as a structural pivot, worn internal dampers directly degrade wheel alignment, steering response, and tire wear.
Replacing a MacPherson strut requires compressing the heavy coil spring to swap out the shock absorber cartridge, or installing a complete 'quick-strut' assembly. A wheel alignment is always necessary after strut service.