In this blog, we’ll explain how leaf springs are made, why they’re still widely used today, and how to install them on a trailer. Whether you’re into DIY or just curious about the process, here’s everything you need to know. Need to purchase leaf springs for your vehicle? Contact us! 

What is the Purpose of Leaf Springs? 

Leaf springs are designed to: 

• Support the vehicle’s weight 

• Distribute load evenly across the chassis 

• Absorb shocks and vibrations from the road 

• Maintain ride height and vehicle balance 

They’re commonly used in light commercial vehicles, heavy goods vehicles, trailers, and off-road applications because of their strength and reliability. 

Step-by-Step: How Are Leaf Springs Made? 

1. Material Selection 

Leaf springs are made from high-grade alloy steel, typically 5160 or 6150 spring steel. These materials are chosen for their high tensile strength, flexibility, and fatigue resistance. 

2. Cutting and Shaping 

The steel is cut into strips and then heated in a furnace to make it malleable. Each strip is rolled or pressed into its characteristic arch shape, often referred to as the “semi-elliptical” curve. 

3. Heat Treatment 

Once shaped, the steel leaves undergo heat treatment. This process hardens the material, improving its strength and springiness. The leaf is then tempered to relieve stress and reduce brittleness. 

4. Assembling the Leaves 

Several leaves are stacked in a graduated pattern, longest on top, shortest at the bottom and secured with a centre bolt. Clamps and rebound clips are used to hold them in position and reduce lateral movement. 

5. Drilling and Eye Formation 

The main leaf (also called the master leaf) is often formed with eyes at each end. These are rolled to accommodate bushings and shackles, allowing the spring to pivot with the axle’s movement. 

6. Surface Finishing 

The final step involves painting or powder coating the spring to protect against corrosion. However, it’s important to avoid excessive coating between the leaves to prevent slippage and weakness at the centre bolt. Notably, powder coating must stay under 350°C to avoid any issues.

The Types of Leaf Springs 

Midlands Road Springs supplies two main categories of leaf springs: 

• Light Commercial Leaf Springs – Ideal for vans and lighter vehicles like the Ford Transit or Citroën Relay. 

• Heavy Commercial Leaf Springs – Suited to larger lorries, off-roaders, and agricultural vehicles like Scania or Mercedes trucks. 

Advantages of Leaf Spring Suspension 

There are several advantages to leaf spring suspension, some of which include: 

• Simplicity and durability: Minimal maintenance compared to coil suspension 

• High load capacity: Perfect for heavy goods and towing 

• Even weight distribution: Reduces stress on the chassis 

• Cost-effective: Leaf springs are easier to manufacture and replace, making them a more affordable alternative to coil springs.

How to Install Leaf Springs on a Trailer 

The leaf spring installation process can be broken down into five main steps: 

1. Lift the trailer using axle stands and remove the old leaf spring (if replacing). 
2. Position the new spring on the axle. 
3. Attach the spring eyes using the front hanger and rear shackle. 
4. Secure the U-bolts tightly across the axle. This is critical: loose U-bolts can lead to movement between leaves and eventual spring failure. 
5. Lower the trailer and double-check all torque settings. 

To learn more, read our installation guide or contact our team at Midlands Road Springs to book your leaf spring installation service. 

Why Buy from Midlands Road Springs? 

We supply high-quality replacement leaf springs for a wide range of vehicles, from light commercial vans to heavy-duty lorries and trailers. Every spring is built to manufacturer specifications and comes with: 

• Free next-day UK delivery before 2 pm  

• 12-month guarantee on standard parts 

• Expert customer support 

• Custom-sourcing is available within 24 hours if you don’t see your spring online 

Shop our full range of leaf springs here 

Looking for reliable, affordable, UK-made leaf springs? 

Now that you understand how leaf springs are made and how vital they are for load-bearing and vehicle performance, put your trust into Midland Road Springs to deliver premium standard leaf springs at a highly competitive price. Explore our shop now or contact us today for tailored support.