Worn Out Springs - Spring Into Action

The common thread that stretches from a Dirt Late Model all the way to the Sprint Cup Series is the use of springs. In the upper divisions of racing, springs get analyzed, inspected, and changed every race because there is speed to be found in spring selection.

A lot of Saturday night teams overlook spring combinations once they find what they believe to be a well handling car. If those teams stay on those four springs for an entire season, the car will differ on how it handles because of the springs losing some of their spring rate and effectiveness.

When I first met Billy Hess of Hess Racing Products, he was looking at a spring that had come out of a customer's racecar. He took the spring and rolled it on his surface plate. The spring stopped halfway across the surface plate and then rolled right back to his feet. To which he muttered, "Absolutely ridiculous." He was upset because the spring was extremely worn out. Take heed: If you are still running on the same springs that you started with two or three season ago, then it is time to invest in a new set.

Under race conditions, springs lose some of their spring rate, and the taller the spring, the more this applies. Teams racing on asphalt typically utilize a soft front-spring setup, accompanied by a large right-rear spring. The front springs undergo a lot more compression then that stiff right-rear spring. This could potentially cause a lot of headaches because of the stress that the front springs experience.

For instance, whenever I purchase a new front spring, I put it in the car and set that corner of the car at its ride height. Once at the track I run 10 to 15 laps before rechecking my ride height, because the spring settles and will not return to its original height. I reset my ride height and run 10 more laps before again checking it. If it is correct, I know the spring has settled as much as expected in the short term.

Quality Of Springs
Another challenge teams face during a season of racing is the quality of their springs. Most springs will increase in spring rate when they are compressed close to coil-bind (completely compressed). This can be demonstrated perfectly with the small springs found in ink pens. Pull the spring out of a pen and notice how easy it is to compress, but you will quickly notice how difficult it is to completely compress that spring. This is because that spring wasn't built with quality in mind.

HyperCo has a new line of coilover springs that are called the Optimum Body Diameter Springs. This is a quality built product that ensures, as that spring is compressed, it will maintain a consistent spring rate. So if you have a 200-pound spring, at 4 inches of travel that spring will still have a spring rate of 200 pounds. This design concept also helps avoid the aforementioned issue of the spring settling.

The design also helps with the weight of the car, as the spring has fewer coils and is lighter. This is easily seen when compared to other springs.

Not All Springs Are The Same
Just because you have two 10-inch, 250-pound springs doesn't mean that they are the same spring. There will be subtle differences between them. One might read 248 pounds of spring rate while the other reads 257 pounds of spring rate. Also, the travel they undergo before they coil-bind will differ. We recently tested our Hooters Pro Cup car at Concord Motorsport Park and we were extremely loose. We pulled the left-front spring and noticed it had been coil-binding. We grabbed a spring that had virtually the identical spring rate, but this spring traveled 3/4-inch farther than the first one before it would coil-bind. This made a huge difference in the way the car handled.