The suspension system is the part of the vehicle that takes the greatest abuse. This is especially true for vehicles that tasked with carrying heavy loads. The suspension system is one of the first parts that needs to be replaced. There are many types of suspension system.
The type of system determines the mounting details required. The solid axle and the double wishbone are two such types of suspension systems.
A solid axle suspension include a solid beam or shaft that crosses from one side to the other of the vehicle. A pivoting connection connects both the left and right ends of the shaft to the wheel spindle, allowing the spindle to turn towards the left of right.
The solid axle design may use leaf springs or coil springs connected from the vehicle structure to the lateral sides of the solid axle beam, therefore allowing upward movement when road bumps are encountered.
Double wishbone uses a pair of triangular parts or called a wishbone stacked vertical to the other. The medial long end of each triangular part is mounted to the structure of the vehicle using a pivoting connection. The lateral pointed end of each triangular part is mounted to either the upper or lower ball joint of the corresponding wheel hub.
The upper and lower ball joints allow the wheel to turn left or right. A spring assembly is typically installed between the vehicle structure and the lateral portion of the lower wishbone, thus supporting the vehicle and damping bumps. The double wishbone has been considered the gold standard for rear wheel drive vehicles for many years.
A typical double wishbone suspension will use a shorter upper wishbone compared to the lower, thus causing the tilting outward of the lower portion of the wheel as the suspension rises during bumps or turns. The shorter upper wishbone helps to keep the tire flat during cornering.
