Postby chickenwafer » Tue Feb 22, 2011 9:14
Struts and shock absorbers are essentially the same thing in their function and design. The difference is a strut replaces some key suspension components because it can accept sideways loads across it's non-compression axis (i.e. they usually turn with wheel movement). Some people use the terms interchangeably but they really are different. Some cars will have front struts but rear shocks.
A coilover is exactly what it sound like- a coil (spring) over the shock body. Some suspension (such as the rear suspension on your 6) have the shock and spring mounted separately. A coilover has the shock with the spring coiling/mounted around it. This makes for a much more compact and effective design. A lot of OEM cars still utilize this design such as the RX-8 and RX-7, for example.
A spring is exactly what you think it is...a spring. The spring is what controls the ride quality (mostly) of the suspension and provides the major dampening. The stiffer the spring (usually measured in lbs/in or kg/in) the worse ride quality, typically. The measurement of lbs/in references how many lbs it takes to compress the spring one inch. So the higher the number, the stiffer the spring. Too soft and the car will experience heavy body roll. Too stiff and the cars suspension will not move, which can induce snap oversteer/understeer physics.
To summarize, the spring effects most "suspension" jobs, i.e. ride quality and handling, and the shock is there to dampen the spring oscillations, essentially to make everything smoother and to limit excessive suspension movement. That is the simplest way I can describe it, but really, shocks play a much bigger role.
