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Discussion Starter · #1 · (Edited)
There's way too much suspension technology out there to cover it all. I'm not going to go into multi-link independent rear, or super-hicas(trademark of Nissan corp), etc... but if you REALLY want to know about the stuff I don't cover, just ask, I'll ammend this post as requests mount.

I'm going to cover mostly the quick and dirty of the basic suspensions of our cars, specifically independent double wishbone/a arm (essentially the same) front suspension, MacPherson strut (for you FWD guys), and leaf sprung, and 4 link rear suspensions. I'll also cover shocks (dampers), bushings (very important!), and sway (anti-roll) bars.

I'm going to do a sister thread in the DIY thread for you drag racing guys about EFFECTIVE, CHEAP, GUARANTEED TO BETTER YOUR TIMES OR I'LL PAY FOR IT suspension mods.

Starting in the basement.

Front suspension for the rwd cars basically hasn't changed so this will pretty much cover all years.

The whole point of your suspension is to keep your tires on the road bed with as consistent a contact patch as possible, ride quality is (generally) a compromise. That being said:

Front Suspension: The basic front suspension is made up of a spindle, containing the wheel/tire and brakes with upper and lower ball joint mounting points, and steering rod mounting point(s). Both the upper and lower ball joints attatch to A shaped arms, with the peak of the A mounting a ball joint to the spindle, and the legs of the A mounting to the frame. This allows the A's to swivel through one plane of movement, and allows the spindle to move in relation, and to swivel as steering input indicates. The lower A arm usually mounts the lower spring perch (the upper to a bracket mounted to the frame) the anti-roll bar mount and the damper mount (notice I used the more uncommon "european" nomenclature for the shocks and sway bars because I feel they more accurately reflect the actual purpose of the respective part).

Note: I couldn't find a photo adequately showing the suspension makeup of our cars. This is as close as I could get. I'll try to get a photo from under mine next weekend while it's in the air with the wheels/tires off (while I'm replacing the motor, WOO HOO!).

Macpherson Strut. The macpherson strut is a great idea. It is an integrated, self contained spring, damper, upper control arm all in one. There is a ball joint on the bottom, and a control (A arm) on the bottom.

The springs should actually be named shocks. They absorb the bumps and dips of the road allowing the body of the car (the main source of mass in motion) to remain in relatively the same place. Springs (on the front end) are coils of specially formulated steel that resists deformation (bending). They are "sandwiched" between the lower spring perch on the A arm, and a bracket mounted to the frame. Even when the suspension is at full extension, the springs are still somewhat compresed.

The shocks, or more appropriately named dampers "dampen" the spring movement. Without dampers the spring would move "above (compression)" and "below (rebound)" static (static being the wheel center's location relative to the body when the vehicle is at rest on flat level ground) in a very unsettling motion until the weight of the vehicles body overcomes the springs rebound forces. The dampers make this compression and rebound less violent, and force the spring to not rebound and compress as many times until static is achieved. Basically a damper is a gas or fluid filled set of reservoirs which uses the suspension compression to move the gas or fluid from one reservoir to another and the rebound to move it back. Kind of like a passive self contained hydraulic ram (ish).

Sway (anti-roll) bars. Anti-roll bars are fascinating to me. They are a spring, specially shaped, (sorta like a wobbly long U) to extend from one A arm, through two mounting points on the body, to the other A arm. The mounting points on the body are bushings that allow no movement but rotational.

The way an anti-sway bar works is that as (for example) the right spring compresses from cornering centrifugal forces (moving the A arms up, into the wheel well) the anti-roll bar moves with it, until the springs " maximum bending " or load force is acheived. After the anti-roll bar can no longer bend, it rotates pulling the left suspension up (into the wheel well) therefore equalizing the suspension load across the body. I know it sounds goofy, but jack your car's front end up so both wheels are extended fully, then jack one tire up.

The anti sway bar on the rear works essentially the same, except it is mounted "backwards" with the "arms" of the "U" on the body, and the two swivelling mounts on the axle (for a solid rear axle, IRS works just the same as IFS).

Bushings. Nearly all of the parts of your suspension that rotate are mounted by bushings. The A arms, and anti-roll bars etc.. Replacing your stock rubber bushings with a polyurethane bushing set will decrease unwanted suspension movement by providing more stable mounting points for said parts.

Rear Suspension:

The rear suspension on these cars can be broken up into two basic types (i'm leaving out the fwd guys on this one, since the independent rear works basically like the front, without steering input, or a torsion beam, which is basically like a live axle setup).

Leaf sprung (see the DIY for you leaf sprung guys that want to drag race, I GUARANTEE i'll improve your 60 foot and overall times.) rear ends use 2 long flattened U shaped spring pack to suspend and locate the rear axle. The ends of the U are mounted to brackets on the frame, with the axle hung from roughly the "center" of the U. A damper is still used to dampen the spring's movement. A sway bar MAY be used also. Very simple system, with major drawbacks. Axle wrap in any high torque car is a problem (see the DIY).

Multi-link rear ends use a number of links to mount the axle to the body, allowing verticle axle movement, and preventing "axle wrap". Most commonly uses coil springs, will have dampers also, usually has anti-roll bars.


Lowering your car will lower the center of gravity. This is usually done (if only lowered a moderate amount to increase cornering performance) by installing shorter/stiffer coil springs, and usually matched anti-roll bars. This stiffens the suspension decreasing body roll, increasing the cars conrering performance further. Bumps will be a lot more noticeable due to the stiffer suspension.

Look for a DIY soon on suspension mods for cornering/road racing to follow up on the drag post.
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