Understanding Springs And Ride Quality - Tech

Cutting coils off of a spring is a different story. Some aftermarket springs come with additional dead coils that alter the free length, which only affect the ride height. Since these coils are not active in determining the spring rate, they can be cut to reduce the ride height without sacrificing spring rate. Factory coil springs, on the other hand, generally need all their coils to retain the spring rate. By cutting factory springs, you'll drop the ride height, but you'll also alter the spring rate, resulting in a stiffer ride. But you can usually get away with cutting about half a coil without adverse effects.

There's definitely a right way and a wrong way to cut coils. Be sure to cut a spring by using a high-powered saw that's able to cut through the coil within thirty seconds or less. Any longer than that creates the potential of overheating that can cause the spring to sag. Always cut in 11/44-coil increments so you don't go too far. This means you're going to spend a lot of time and effort fitting and refitting the spring, but it'll help prevent any dramatic changes that you may later regret.

When cutting a factory spring, you may find that the car occasionally actually sits higher at first. This is because the spring is getting stiffer as its live coils are cut. Continue cutting in 11/44-coil increments and you'll eventually reach the breaking point and get the ride height you're looking for. If you hastily cut in larger increments, you may go beyond the breaking point, ruining the springs and ending up with a car resting on its bumpstops.

Scaling Your CarScaling a car is the ultimate way to measure and adjust a vehicle's weight distribution. An individual electronic weight scale is placed underneath each tire and connected to a digital display that reveals the exact weight on each corner. By knowing the weight of the vehicle, you can see where you need to add or remove pounds to configure the vehicle for optimum traction. For open tracking or corner carving, you want the weight to be equally distributed. If your car weighs 3,000 pounds, the ideal setup would have each corner weighing in at 750 pounds.

During cornering, weight is shifted laterally to the outer tire. The more weight that is shifted onto the tire, the easier it is to lose traction. By knowing the car's weight at each corner, you can adjust the spring rates to help control the amount of force being transferred for maximum traction. Neat stuff, huh?

Drag vs. Sport vs. Open Track Spring RatesSpring-rate combinations vary according to the weight and intended usage of each vehicle. We asked Hotchkis Performance to recommend spring rates for three different types of driving use on a 3,400-pound '66 Chevelle packing a small-block. While these ratings only pertain to our imaginary example, they should give you ballpark figures on the type of spring ratings that are required for various applications.