Tech Question - Spring Settling

Will leaf springs tend to settle more than coils especially in the rear? - Mike

All springs will settle over time, however I believe your question should be "How much will springs settle shortly after being installed?" The answer is very little providing the springs are the right springs for the vehicle. Springs support weight and this is why it is so very important to be honest about the changes made to the vehicle. For every change there can be a change in the amount of weight the springs will be required to carry. Another function of rear leaf springs is to control axle windup which occurs both on acceleration and braking. So engine size, torque and horsepower may come into play. Standard design stepping may be alright or if the power is such special stepping my be required. Go to Spring Tech Information and download "Spring Tech 101" to learn about the terms used. Correctly manufactured springs, both leaf and coil, are shot peened which removes stresses in the metal which occurs during the heat-treating process. The life of the spring is not only increased because of shot peening, the spring will not continue to take "a set" once it is installed. While getting the overall stance correct will be one of the final steps in building the vehicle, planning for it must happen early in the building process. Getting that look can be tricky but most of the time it can be achieved. Because springs support weight, the final look of the vehicle can not be achieved until the vehicle is 99.98 percent done. Remember all those parts which are waiting to be installed have weight. And the location of those parts determine how that weight will be carried by the suspension. Having you and your 4 buddies stand on the front bumper does not distribute the weight in the same fashion as an installed engine and tranny does. Other areas to watch for trouble include; Clearances - the look might be right but things are hitting underneath. Steering -, the look may be nice but you can't turn the wheel. Ride quality - the look may be nice but it rides like a buckboard. The vehicle being built is custom. Things are being done to it and for it that were not originally designed for it. More than once you will install, remove, tweak, re-install, re-remove, re-tweak and repeat the process over and over to get it "Just Right." And the springs are no different, they may have to be installed more than once to get the stance "Just Right." The final test of the springs is drive the car like you stole it. Work those springs. Bounce them. Flex them. Stomp on the gas. Stand on the brakes. Make them do their job, after all you built the vehicle to have fun, so go have some. So how much settling is "very little?" Correctly matched springs will settle no more than 1/4 to 1/2 Inch once the car is finished and driven. Any more than that means something is not right. And, no leaf springs will not settle any more than coil springs, nor will coil springs settle any more than leaf springs. Where do things go wrong with springs that settle too much too soon? Bottom line is over 99% of all spring problems are either installation related, a result of the customer not being honest about the changes made to the vehicle or making more changes once the springs have been built.

Springs that continue to settle quickly after they have been installed are over-stressed springs. Over-stressing is only caused by too much weight on the springs. Moving on, all springs have a finite life, that is one day they will break. How long this life is depends on their use, the loads they have been asked to carry, the roads driven on, how the vehicle and the suspension are maintained.

Any leaf that is broke at the axle shows that the u-bolts have become loose. And once one leaf breaks other leafs will also began breaking.

Can a broken leaf cause an accident? Yes it can. Depending on which leaf it is and where it breaks and does the broken leaf stay in the spring pack or not. So don't mess around, replace broken springs ASAP.

Because of the dangers of a broken spring, are mono leaf springs a good thing? Mono Leaf Springs will help you decide.

And Mike, you thought you asked a simple question, didn't you? - Mike