A leaf spring is a steel plate or stack of damped steel plates. These plates are from spring steel, which is heat-treated middle-alloy steel. The results of heating are to provide a leaf spring with the ability to flex without permanent deformity. There are two types of leaves used in trucks multi-leaf and full taper. The principal purpose of leaf springs is to act as a cushion between the axle and chassis to protect the vehicle and cargo.
Why Trucks Have Leaf Springs
Leaf springs support the truck’s chassis weight, which can be heavy depending on its size. When the leaves are well functioning, they ensure you’ll have a smooth ride. The springs also hold the axle in place and suspend the vehicle’s weight, thus not necessary for control arms.
It’s also easier to add extra springs for extra stiffness and load-carrying capacity. Even if one spring breaks, the others will still support you until you get to a repair shop. The springs also relieve pressure on the axle, which is placed on by extra weight. Again, they help keep tires alignment and absorbs the shock that results from driving over potholes, bumps, and rough roads.
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What Do Leaf Springs Do on A Truck?
Leaf springs are the main elements keeping the wheels moving smoothly over bumps and potholes without transferring the truck’s body’s impact. The springs make the ride smooth and easier on any load you may be carrying. However, it would help if you match leaf springs to your truck’s weight.
Leaf springs come in many non-identical load capacities for the same type of truck. The springs also help maintain the tire’s grip on the road and regulate the wheelbase length when speeding or slowing down. Springs offers a variety of ways to increase the load capacity of your vehicle. Standard and heavy-duty leaves are for towing and hauling heavy loads for any truck model.
Pros and Cons of Leaf Springs
The advantages and disadvantages are as follows;
Simple Design
The leaf springs suspension setup supports the axle. This simple design makes it easy to install, repair, and upgrade. You can replace individual leaves or adjust flexibility by adding or removing plates. Its also more comfortable to modify leaf springs to enhance performance, increase the ride height, or improve stability and handling.
Reliability
The springs are a reliable form of suspension. That’s why they are in much use in commercialized vehicles. Their strength and heavier weight also add to their reliability. Higher unsprung weight in a truck can increase the wheel’s contact with the ground; this results in better traction on a muddy or slippery surface.
Superior Hauling Power
The springs have a tight structure that allows them to distribute weight across a wider area. They can handle heavier vertical loads as compared to coil springs. They can support heavier vehicles’ weight, and that’s why many trucks come equipped with leaf springs due to higher hauling power.
Leaf Springs Cons
Despite the springs been useful, they still have their drawbacks.
Reduced Approach and Department Angles
They fail to allow the same approach departure angles as coil spring suspensions. Their fitting under the vehicle’s frame can impede wheel movement when too steep on incline or decline. Leaf springs can also alter shackle length, and this will add some height. It still affects caster angles, which can negatively impact others.
Prone to Axle Wrap
Axle wraps when the rear axle housing twists when heavily accelerating. The wrap can break leaf springs, make driveshaft movable, and break transmission.
Shackle Inversion
The inversion occurs when the shackle moves past its designated axis of movement and gets stuck. The inversion occurs when offloading. The entire suspension becomes inoperable and can cause further damage to the vehicle if you insist on driving.
Stiffness
Leaf springs are stiffer than other suspension forms due to the steel construction and the tight package, where they are bolted and clamped. Therefore, the springs lack a comfortable ride, and that’s why they have lost their popularity.
How Long Do Leaf Springs Last?
How long your leaf springs will last depends on various factors ranging from your vehicle’s age and frequency of use to stress applied to them and environmental factors. For instance, if you use your car to travel and later keep it in the garage, your springs will last forever. But if you use your truck to travel regularly, haul heavy loads, and tow to maximum capacity, it will shorten your leaf springs life expectancy.
The use of products like super springs and replacing shackles, hangers, and bolts will help springs last longer. Typically, a set of leaf springs for an ordinary pickup truck will have a life span of 200,000 miles. This number can change as some vehicles will break their springs in less than the 200,000, and others will go beyond the figure mark.
Some of the factors that can make your life springs fail before their expected life expectancy include;
- Loose U-bolts: leaf springs center bolts shear or break when you fail to torque the U-bolts properly. You should check U-bolts regularly to ensure they are tight, especially after installing new truck springs.
- Corrosion and fatigue: result due to a combination of time and elements. The amount of weight you haul and where you live, roads you drive on will play a role in leaf springs shelf life. If you use a truck on salty roads, ensure you spray corrosives off the spring to prevent corrosion.
- Over-loading your truck springs: can cause fatigue on your springs and soon fail. If you can prevent overloading, add an overload kit like a suspension air bag kit or set of helper springs. You could also add a leaf to increase the spring pack.
- Weld splatter results from welding a body or accessories to your truck in the same area as your leaf springs. A small amount of weld splatter can be disastrous to your spring’s life.
How Do I Know if My Leaf Springs Are Worn out?
Some common signs that leaf springs show as an indication they need replacement include;
- presence of cracks and fractures
- change in the way your vehicle drives
- vehicle leaning on one side when there is no load
- feeling even the small bumps as you drive
- your truck nose dives, lean back, or rolls with the momentum
How to Maintain Your Leaf Springs
The best way is through a routine inspection at the first indication of trouble. If the leaf springs are coated with grit, grime, or dirt, clean them off with a wire brush. If they are not in good condition, it’s best to replace them.
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To clean the springs, lightly spray degreasing fluid and scrub with the brush until you remove all debris. If there isn’t a lot of dirt, you can use the wire brush. As you are cleaning, inspect the springs for cracking, chipping, or other signs of wear. After the leaf springs are clean, you can apply a silicone lubricant, though this is not necessary.
Conclusion
Leaf springs do a perfect task, especially for commercialized trucks since they are durable and haul heavy loads. They also have a simple design to install, repair, and upgrade with cheap costs involved. However, they still have their downfalls like stiffness, altering shackle length, and this may have made them unpopular. Proper maintenance of leaf springs will ensure a safe ride while towing by keeping the truck’s wheels grip on the ground and its cargo in place.