Simply Shocking! A Guide to Shocks and Coil-Overs
Every vehicle on the road is equipped with a sprung suspension of some sort, whether it has old-school leaf springs, coil springs, coil-over shocks, or even torsion bars engineered to absorb bumps and road variations, support the weight of the vehicle, and to keep the tires planted firmly on the ground. Suspension springs are essential to produce a smoother ride; however without a damper, most often called a shock absorber, the vehicle would bounce and wobble continuously, dive excessively under breaking, and squat substantially during acceleration. In short, it would be a sketchy driving experience, at best.
Shock absorbers do exactly as their name implies: absorb the impacts and control the rebound of the springs and suspension movement. Proper shocks are essential to deliver not only a smooth ride, but also to provide your car or truck with the handling characteristics, braking control, and overall safe performance that makes it comfortable and enjoyable to drive.
Shocks have been around since before the automobile was invented, though in a friction form which you’ll still find on a few very early cars and hot rods. The hydraulic shock has been around for more than 100 years and continues to be refined for improved performance, control, and racing. Today, the hot rod industry has countless variations of dampers, including monotube and twin-tube shocks, adjustable shocks, coil-overs, and more. But what’s the difference, which one is right for your application, and what kind of expert advice can help you get the best performance and handling out of your suspension? To find these answers, read on!
Shock or Coil-Over?
When you start researching suspension upgrades for your project, you’ll find a lot of info and options about shocks as well as coil-overs. But what exactly is the difference? A shock absorber is separate component that works in conjunction with a coil or leaf spring to dampen the spring’s oscillations and movement. A coil-over shock achieves the same goal but combines a coil spring and the shock into one component.
As you would expect, coil-overs cost more than standard shocks and have long been regarded as more of a high performance and racing component thanks to their ability for advanced tuning and ride height adjustments in a compact, lighter weight package. In the past couple of decades, though, coil-overs have become a popular choice in the classic and muscle car arena thanks to suspension companies designing more bolt-in options and covering more applications.
Coil-over benefits aside, there have also been substantial advancements in direct-fit shock absorbers, including single- and double-adjustable options that are available as an easier and more affordable upgrade for many vintage rides.
What is Adjustable?
So, what exactly is adjustable on a shock absorber? A single-adjustable shock gives you the ability to adjust the rebound action of the shock and sometimes the compression movement. Rebound refers to the extension of the shock, while compression is when the tire and suspension are pressed upward into the chassis. An adjustable shock lets you tune the rate of damping action.
For most street cars, a single-adjustable shock will provide adequate adjustments, but if you’re more serious about handling or plan to run autocross for fun, a double-adjustable shock would bring that much more tuneability to help achieve your precision handling goals.
Coil-overs also bring two other important adjustments to the table. First is an easier ride height adjustment by moving the position of the coil spring over the threaded shock body. Second is the spring rate of the installed coil spring. Spring rate is the amount of force required to compress a spring one inch. Knowing your vehicle’s weight, the shock travel, and even the mounting angle are keys to selecting the proper spring rate for your specific application and usage.
Shock Mounts and Measuring
Since we’re talking about hot rodding, there’s a good chance that your project has been customized in some manner to where finding the proper length shock isn’t as simple as a year-make-model lookup. In this case, there are a few simple measurements you can share with a shock or coil-over manufacturer or dealer to get the proper fitting shock you need.
In the case of a street car and cruiser, you may get away with just the ride height measurement. Start with the vehicle sitting at your desired ride height and measure the distance between the upper and lower shock mounting points (note that this measurement varies depending on the mount). In many applications, a shock manufacturer can make a pretty good recommendation based on just this measurement, but in performance applications, you’ll need to provide an extended and compressed measurement, as well. You’ll also be asked about the type of mounts, which could be a through-bolt eyelet or spherical rod end for more adjustment, a threaded stud, a T-bar, or a combination of these options.
Double Adjustable for Street and Track
Compromise is not a word performance enthusiasts like to use, and thanks to Summit Racing’s Double Adjustable Coil-Overs, drivers don’t need to compromise between performance and a luxury ride. Summit’s coil-overs allow you to easily adjust the compression and rebound settings so you can have a softer ride for cruising, but easily dial the settings in for hardcore handling.
The coil-overs feature clear anodized aluminum bodies, precision-machined aluminum pistons, and centerless-ground, hard chrome-plated piston rods for durability. The coil-over springs, available separately, are CNC-machine coiled from high-strength chrome silicon steel wire, shot-peened to aerospace standards, and preset for extra durability. They’re available in different lengths with spring rates ranging from 80 to 650 lbs./in. to fit a variety of applications.
Street & Strip
With more than 40 years of experience in racing driveline and suspension technology, Strange Engineering understands what hot rodders need in a performance shock or coil-over. The company’s lightweight aluminum coil-overs are designed to reduce weight, optimize suspension performance, and allow for easy tuning for changing track conditions. They also offer several valve packages to accommodate street, strip, and road race applications for many different muscle car applications.
Strange coil-over shock bodies, eyelets, spring seats, and adjuster nuts are precisely machined from aircraft-quality aluminum before being assembled and inspected and dyno tested to ensure proper valve seating and durability. The rebound adjustment helps get your setup dialed in precisely as well as the adjustment nut to alter spring tension.
Ride Quality with Ridetech
Nothing influences how your car rides and handles more than its shock absorbers. A shock’s primary function is to control the oscillations of your car’s springs to keep your tires in constant contact with the road. With more than 30 years of experience in performance suspension systems, you can bet that Ridetech’s 1.5-inch RQ-S steel body shock absorbers are up to the challenge of providing your vintage car or truck with the best ride possible.
RQ stands for “Ride Quality,” and these adjustable shocks will deliver the smooth ride you desire thanks to their monotube design with a larger piston and precise valving. They also feature 24-position rebound adjustability along with a heavy duty ½-inch shock shaft – all at an affordable price and backed by Ridetech’s exclusive 1,000,001-mile warranty. Available for a long list of classic applications and they’re also offered in Ridetech’s popular StreetGrip suspension systems.
G-Body Coilover Kit
Fans of the popular GM 1978-88 G-Body, including the Buick Regal, will be excited to learn about Aldan American’s complete kit to convert factory front and rear suspensions with fully adjustable coil-overs. Aldan’s coil-overs provide full tuning control of the shock speed for a smoother, more responsive and controlled driving experience, and also deliver ride height adjustment.
Available with Aldan’s Road Comp single-adjustable or Track Comp double-adjustable coil-overs, you’ll be able to achieve 2-inches of lowering in the front and up to 3-inches in the rear. The Aldan spec’d cold-wound, linear coil springs provide greater consistency with a more capable ride and the front coil-overs are designed fit into the factory spring pockets for precise fitment. Aldan has done its G-body homework and includes all the brackets and hardware for a bolt-in suspension overhaul!
Classic Mustang Pro Coils
When compared to today’s handling and ride expectations, early Mustangs – like most other vintage cars – leave a lot to be desired. To help bring your classic pony up to modern standards, QA1 offers its Pro Coil System that provides ride height and shock adjustment without any welding, cutting, or fabrication.
The Pro Coil System features a 10-inch spring with a 350 lb./in. rate over QA1’s single-adjustable coil-over with 18 settings of rebound/compression control. This adjustability allows you to fine-tune the ride quality and handling simply by turning a knob, plus you can easily lower your Mustang’s front end by 2-inches for a lower center of gravity and improved looks. The Pro Coil System works with factory control arms or QA1’s tubular arms and sway bars.
Re-do Your Mustang II
A Mustang II front end swap has been used for decades on street rods and pony cars, most equipped with coil spring and shock setup. Speedway Motors can help improve the handling and deliver the exact ride height you want on your Mustang II-equipped car with its true bolt-in Coil-Over Conversion Kit.
Speedway’s Mustang II coil-over kit is based on an AFCO chrome plated steel monotube shock absorber with a fixed valve rate. A slip fit threaded sleeve and retainer is fitted over the shock to accept a black anodized lower spring perch and locking collar. Speedway offers four different chrome silicone springs in rates 375, 500, 600 and 700 lbs./in. for a controlled ride and to ease ride height adjustments.
A-Body Rear Coilover Conversions
The Detroit Speed GM A-Body Rear Coil-Over Conversion Kit is designed to bolt in to the rear of any GM A-body vehicle. The base DSE coil-over package offers extensive ride height adjustability with the company’s exclusive valving for A-bodies. You can also select from a single- or double-adjustable coil-over for optimum control over low speed and high speed rebound.
For the rear, DSE’s ultimate package features a monotube remote-reservoir coil-over set that offers separate fluid canisters for optimum adjustability and improved heat dissipation. This system is based on JRi’s double-adjustable shock featuring two independent adjustments creating an enormous range of settings to achieve your handling expectations for performance and ride quality. DSE has GM A-Bodies handled with complete Front and Rear Speed Kits.
Fox Body & SN95
Chris Alston’s Chassisworks offers its own direct-fit shocks and coil-overs for a variety of applications, along with a Custom Builders Series coil-overs. The company’s unique line of VariShock Coil-Overs is available in lengths ranging from 9.67–17.24-inches, with travel lengths of 2.8–7.15-inches. Together there are a bunch of configurations available that can be used on nearly any OEM or aftermarket suspension – including the Fox Body and SN95 Mustangs.
Chassisworks’ VariStrut Coil-Over Conversion is a bolt-in suspension-tuning solution for 1979–04 Mustangs. These struts feature double-adjustable QuickSet 2 valving to let you quickly adjust the rate of compression and extension independently, with the ability of adjusting spring preload and easily changing spring rates when tuning the suspension. The VariStrut kit includes springs, upper and lower spring seats, and a spanner wrench.
Nova Shocks for Leafs
The crew at Ohio-based Church Boys Racing specializes in making 1962–67 Novas perform, handle, and look really good. They also realize that these cars were never known for the best handling capabilities, so they’ve spent a lot of time testing various components and systems to improve the little Chevy II’s ride and feel – such as these double-adjustable shocks from Viking.
These shocks are direct replacements for the factory leaf spring setup and offer 19 separate adjustment positions for compression and rebound. The lightweight shocks have a clear anodized finish and use a beefy 5/8-inch hard chrome plated piston rod. The shocks have a two-year material and workmanship warranty and provide a great standalone upgrade or will complement Church Boys’ front Coil-Over Conversion kit.
Straight Axle Chrome Shocks
Posies Rods and Customs has a tradition of testing its products and cars through real-world adventures on the highway. It was these road trips that lead to the creation of the company’s SuperSlider Springs to help hot rodders improve the ride quality and stance of their builds. That is also why you’ll find Bilstein’s SS4 shock absorbers on the company’s site.
The chrome finished Bilstein SS4 shock absorbers work as good as they look. Designed specifically for custom street rod applications that require unique lengths and valving, these shocks feature a 36mm digressive working piston, smooth body, 5/8-inch polyurethane bushing mounts and are available in various lengths. They can be mounted in any position and are also available for other classic car applications through Posies.
Classic Shock Resource
The suspension experts at Eaton Detroit Spring have been manufacturing leaf and coil springs for American cars since the 1930s. They also know a thing or two about shocks and realize that many classic car and truck owners would simply like an affordable bolt-on shock upgrade for their vehicle that will deliver a smooth and comfortable ride.
In addition to offering shocks from QA1 and Viking, Eaton also offers several different low-pressure gas shocks from KYB. The KYB Excel-G shocks deliver a softer ride comparable to the hydraulic shocks your vehicle likely came with originally. For a slightly stiffer ride, the company also offers KYB Gas-A-Just shocks. Best of all, Eaton’s website makes it easy to find several shock options for just about any vintage vehicle offering.
Photos courtesy manufacturers
