Etan Trampoline spring- hot dip galvanized 140 mm set of 10. How do you know your trampoline springs need replacing? Obvious reasons are that the springs are rusted or broken, producing too much noise when jumping or children complaining that the trampoline no longer jumps fine. Do you want to check it? Then take a spring out of the trampoline, if the curves of the spring remain open it needs to be replaced. A good elastic spring should spring back immediately. Note: if you want to replace the springs of your trampoline, measure the size you need. The spring must first be removed from the frame before you can measure it. Preferably choose a spring that is not stretched to get the best measurement results. To measure the length of the spring, choose a spring that is not stretched. To determine the correct size of the spring, measure it from hook to hook. When replacing a spring, a small difference in length is acceptable. For example, a measurement of 14.5 cm can become a 14 cm spring.