You go over a bump, and a spring (or gas in a cylinder) gets compressed. That energy doesn’t evaporate; it has to be released, pushing the cabin up. So why does a suspension make the ride cushier? Where does that energy go?
Virtually all car suspensions have both springs and shock absorbers that connect the wheels to the rest of the car. Shock absorbers are more or less a set of cylinders inside of other cylinders and are made so that fluid goes through small holes as they work. The more force you apply to a shock absorber, the more it will resist moving in and out. Springs are… well, they’re springs…
When you go over a bump, the bump pushes up on the car but for only a short while. The springs absorb this energy and release it gradually. The shock absorbers dampen any movement by dissipating the energy produced as heat. The end effect is that the spring tries to bounce when the car hits the bump and the shock absorber stops the bouncing, at least that’s how they’re designed nowadays.
Yes, the shock absorber (damper) can make the energy “evaporate” (i.e. turn it into heat). But part of the energy goes into pushing the wheel down after you’ve gone over the bump.
By the way, even the most primitive suspension provides some sort of a damper. You know those “leaf springs” - stacks of thin strips of wood or metal, used on old trucks and horse-drawn carriages? The strips rub against each other, acting as dampers. If you use just a single strip of metal, there’d be no damping and it would be very bouncy.
Hey, my old '67 Camaro had single leaf springs in the back, and it wasn’t too bouncy… Well, until I installed the 425 HP engine. Then I destroyed them in about a week. I also learned all about ‘flutter’, as the back wheels hopped all over the place and threatened to rip themselves out of the car every time I accelerated hard.
A car’s suspension basically consists of two things: Some type of spring and some type of shock dampener.
The spring can be a bundle of flat strips of metal (leaf springs), round coiled springs (coil springs), or straight, round metal bars (torsion bars) although these aren’t used much, if at all, anymore.
The dampener is either a shock or a strut. A strut is nothing more than a shock absorber with a coil spring built it.
The key thing to realize is that the springs, not the shocks or struts, are what hold the car up and do most of the work. The shocks just act to fine tune the springs, smoothing out their, um, bounciness.
I never tire hearing someone who has a car with a sagging rear end say, “It needs new shocks”. No, it needs new springs. Shocks won’t raise up a cars suspension at all.
Yeah, I know. Air shocks will. But air shocks aren’t really shock absorbers, they’re poor-man’s new springs.
I thought air suspensions were more expensive. On my fathers 1997 Cadillac, it had an air suspension, and the ride was cushy cushy.
On my Pontiac Firebird, I had springs, and the ride was not cushy.
‘Air suspension’ is a manufacturer’s term and can mean alot of things.
Air shocks are things you buy at a hot rod shop. They look like shock absorbers and have a tire valve fitting on them. You inflate them to lift the car up. Thing is they don’t give a very good ride. Like I said, they’re basically a quick & dirty (& cheap) way of fixing a worn out suspension.
I’m not familiar with the air-shocks you speak of. I am familiar with air-bags, however, which are the most common form of pressurized air suspension (shocks being pressurized oil in most cases). Another thing that sounds similar to what you describe is adjustable shocks, struts, or coil-overs, such as Koni, KYB, AGX, and so on. These have adjustable valves for oil-flow that change your damping rate dependant on the setting. The most common modes are two-way, three-way, four-way, and five-way adjustables, with infinitely adjustables being somewhat more expensive, but more compliant and easier to tune to your ride.
Leaf-springs are normally replaced these days with either a coilover conversion, airbag conversion, or a mono-leaf spring. These mono-leaves are just that, a leaf that provides spring rate and damping in a single piece.
–Tim