It’s almost spring… and pun intended, it’s the time of year people begin to check their trampoline springs. The first question we receive about springs is, “When should I replace a spring?”
The answer is if you see any of the following:
The second question we receive is, “How many springs should be in need of replacing before I change them out?” The answer to this question is, one! Yes, even if just one spring is stretched, broken or rusting, we recommend replacing it immediately. This is for safety reasons (uneven bounces) and also because when a spring is not working, it will cause additional stress to its peers or to the mat itself, potentially causing it to tear. So when you have even just one bad spring, it’s worth taking the time to replace it.
The last question we often get about this topic is, what should someone look for when buying replacement trampoline springs? Or if I’m looking to buy a trampoline, what should I look for in the springs?
Let it be known, springs matter! They are the critical part that help to create the bounce that trampolines have. Think of them as the “engine” of your trampoline.
So here are a few additional tips…
Metal or Elastic. First, make sure your trampoline has metal springs. Yes, there are some backyard trampolines that now use elastic bands to offer a spring-free experience. Have you ever seen elastic keep its tension factor for a long time? No, we have not either. Steel in our opinion lasts longer and provides for more consistency in the bounce. Our recommendation for backyard trampolines is to avoid the spring-free types. There is however one exception. We have seen a number of springless exercise trampolines that are well manufactured and provide a good consistent bounce. Remember, however, that these are intended for indoor exercise to cushion the user – not for full on jumping.
Galvanization. Second, ensure that the springs are galvanized. What is galvanization? It’s a process of covering or coating a steel object with a protective zinc layer. The idea is that zinc is much more corrosion resistant than ordinary steel. Depending on the circumstances, environment and ventilation, zinc coating can help preserve steel for decades by preventing any rusting. If your springs do not specifically say that they are galvanized, they probably are not and you should avoid buying them.
Size and number of springs. The size of the springs does matter and makes a big difference. As a general rule, the more springs and the longer the spring, the more bounce that will be created by the jumper. Why? It comes down to physics. It’s a combination of Hooke’s and Newton’s laws of physics. Hooke's law states that the force or energy used to extend a spring is proportional to the length of extension. So the heavier the weight bouncing on the trampoline, the longer the extension. Newton's third law states that for every action, there is an equal and opposite re-action. So as those springs get stretched out, they eventually snap back causing the jumper to bounce back into the air. More springs allow for a better bounce and the length provide the snap back. Shorter springs create a rougher and choppier bounce while longer springs provide a smoother bounce preferred by most jumpers.
Shape. We recommend dual tapered springs. While these may be slightly more expensive than non-tapered, the performance is better. Tapered compression springs provide more lateral stability and because of their shape, are actually stronger than straight springs.
So in summary, here are a few tips about trampoline springs…