We receive countless questions about suspensions on a weekly basis. The most common of these relate to the durability of leaf springs. We've compiled the top three questions with our answers to hopefully help you better understand what to expect from your leaf springs in regards to how well they will hold up and what causes them to wear out.
Do leaf springs break?
Yes, leaf springs do break. They are a heavy wear part meaning they are subjected to a large amount of abuse. This abuse comes from repeated flexing, rubbing, sudden compression and decompression. Springs are the buffer between your car or truck and the road. Without your vehicle’s suspension, your journey down the road would be a very violent and uncomfortable one. The rest of your vehicle wouldn’t last very long either without the cushion provided by its suspension.
How long do leaf springs typically last?
How long your springs will last is a bit of a complex question. We must take several factors into consideration. The major factors include age, mileage, the type of roads driven on, and load weight carried by your vehicle. These are the things that will tell the most about the condition of your springs.
As your springs age, they typically take on miles which leads to wear and tear. Over time, the steel in your springs stretches out and inches its way towards the breaking point. Think of it like a metal wire coat hanger. If you take the hanger in both hands and bend it back and forth repeatedly, after a few moments the metal will break. Leaf springs operate on a similar principle, they just take a lot longer to reach that breaking point. Even if your vehicle sat from the time it was brand new for the next 30 years, and was never driven, it would still slowly be stretching the steel just under the vehicles own weight. This would of course take a lot longer to wear the springs out as opposed to normal usage, but over time you would find that the vehicles height would sag down.
Once we add mileage to the equation, it greatly accelerates the steel wearing out. As you drive your vehicle, the springs articulate and bend as they absorb the bumps on the road. The rougher the roads, the harder the wear is on your springs. A truck that drives only on smooth paved highways will put a lot less wear on its springs as opposed to one which drives off road or over streets that are full of potholes. The more the spring flexes, the more it stretches and the faster it breaks down.
Now if we add additional weight onto a truck, the springs will be under greater pressure than normal, accelerating the stretching of the steel. Added weight can also cause greater articulation in the springs over bumpy roads, which again, breaks down the steel faster.
Too much weight on a vehicle’s springs will often times result in premature breakage. Springs have capacity ratings which dictate the weight limit for which springs can carry. Loading your springs beyond their weight limit may not result in breaking right away, but it will certainly shorten the life of the springs beyond what is considered normal.
The factors discussed above will play a major role in how long a set of leaf springs will last.
How do I know if my leaf springs are bad or need to be replaced?
There are some signs as well that can be a good indicator as to whether or not the leaf springs are worn out, are bad and need to be replaced. A few of these include:
- If the spring has lost its uniform curve (arch) that runs along its length (especially if it has any humps or waviness along its arch)
- If the leaf ends are digging in and cutting into the leaves above
- If the middle of the overall pack has collapsed and appears to be pinched down while the ends of the leaves appear fanned out and separated
On average a set of leaf springs for a standard pickup truck or van will have a lifespan of about 200,000 miles. This number is not written in stone, and some vehicles will break their springs with far less than 200,000 miles on them while others will go well beyond the 200,000 mile mark before they break. It’s different for every vehicle, but hopefully this has given you some valuable information that will help you to identify when it’s time to replace those worn out leaf springs.