Purpose built coil-over shock / spring assemblies have been around the racing industry for a long time, but Carrera claims to have developed the coil-over shock system in the early seventies using a grooved shock, snap ring and threaded sleeve tube. This has since become the most popular shock / spring package in the automotive industry. The coil-over system offers many advantages over the standard production car shock / spring arrangements, including compact packaging, easy ride height and weight balance adjustments, easy servicing without special tools and quick and easy spring rate changes. Coil-overs are used extensively in our Fiero suspension upgrades.

The following is a breakdown showing the various components that make them work :



SPRING SEAT. This extremely light part is machined from very strong 6061-T6 aluminum alloy. It centers the spring around the piston shaft of the shock and provides a shoulder for the spring to press against. Slotted on one side, it allows easy removal of the spring without the need for special tools and is drilled for tie wraps and cross drilled to accept hitch pins.

HITCH PINS. The hitch pin installs across the slot in the spring seat and prevents the seat from moving off center or slipping off the rod altogether. Because it snaps in and out quickly and easily by hand, it eliminates the need for cotter pins & pliers and allows for easy removal of the seat and spring.

TIE WRAPS. Installed through the two holes in the spring seat, they hold the spring and seat together even when the suspension is unloaded. Together with hitch pins they make sure the spring returns to its desired position each time the suspension is unloaded, regardless of spring dangle.

FLOATING WASHERS. This is a hard flat washer which fits between the spring and the adjusting nut. It acts as a bearing, making adjustments much easier.

ADJUSTING NUT. The aluminum nut is designed to center the spring around the shock body and hold it against the spring seat. The inside bore of the nut is threaded to match the threaded sleeve onto which it is installed. When it is rotated, the spring is adjusted up or down in relation to the shock body, thereby raising or lowering the vehicle and transferring weight away from that particular corner. The perimeter of each nut is drilled to fit a spanner wrench should hand adjustment prove difficult. Whenever possible, adjustments should be made with the suspension unloaded.

THREADED SLEEVES. Machined from the same material as the spring seat, the inside diameter of the sleeve is bored to slip over the shock body. The shock body is grooved near the fixed end to accept a wire snap ring. The counter bore in the threaded sleeve is a precise fit over the snap ring, holding it in place on the shock. This in turn provides a shoulder to support the sleeve. The outside of the sleeve is threaded with a coarse, low friction, acme thread which allows easy rotation of the adjusting nut, even when grimy. It is very unlikely that the sleeve would slide down over the snap ring, but in that event , it would hit the shock mount making sudden collapse impossible-- a very safe system.