Age is not always synonymous with inaccessibility or throwing something in the waste. Leaf spring suspension technology is a good illustration of this. For modern cars, leaf springs are about as extinct as they can be.
Yet, if you look at the suspension of passenger buses, coaches, trucks, trailers, vans, and other heavy-duty vehicles, you’ll see leaf springs are very commonly used. That means there is something advantageous that helps the leaf spring suspension technology continue to flourish.
At the same time, it is not a coincidence whatsoever that modern suspension technologies have taken the place of the leaf spring suspension system. Maybe this is because of its drawbacks. So, what are the advantages and disadvantages of leaf spring suspension? Read on to learn what we found out.
Leaf Springs – History and Basics
The 18th century witnessed the development of the leaf spring as a quality design for a mounting plate when it came to the carriage. This plate is also known as a leaf spring, and it has been the first suspension system used on vehicles. The leaf spring design hasn’t changed much throughout the centuries.
Ordinary leaf springs use several steel leaves stacked one on top of the other in a looped pattern. Tapered leaf spring setups are generally oval-shaped from springs made from flexible steel. As pressure is applied, the spring makes its way back to its original shape through actuation, but it returns to its unaltered state by going through damping.
The bottom of the leaf spring is typically exposed to severe forces. First, it is cut into rectangular pieces and attached with metallic clamps to the middle and larger ends. It’s then connected to the axle using large U-bolts to hold it in place.
The flexibility of the steel springs contributes to a damping effect in the car suspension for flexibility and control while traveling. Due to this, the leaf spring setup has long been proven as a successful solution on big rigs and in military vehicles.
Read also: Why Do Trucks Still Use Leaf Springs?
Advantages and Disadvantages of Leaf Spring
As you can see, the leaf spring suspension system features a quite simple design. The simplicity of this suspension design inhibits both advantages and disadvantages. Let’s have a look at those:
Advantages of Leaf Springs
Leaf spring has many tremendous benefits. However, below are some of the most useful advantages of leaf springs.
- Versatile Suspension System
The leaf spring setup acts as a versatile unit by performing several functions. Yes, you will also find similar outcomes from modern suspensions, but this may require additional hardware.
For instance, the primary function of leaf springs is to support the chassis weight. But, at the same time, leaf spring suspension has the benefit of controlling chassis roll more effectively. Leaf spring suspension controls rear end pat as well, soothes the impregnability of the axles, and works in the same way as a Panhard bar. Leaf spring suspension controls braking as well as a rear stabilizer.
- Less Body Roll
This advantage is well-judged when a race car is equipped with a leaf spring suspension setup. In the leaf-spring design, the springs are mounted in a fairly wide spring base, which keeps them from twisting. The fewer the roll tendencies there are, the less force goes to the rear. In addition, the moment arm can be quite low, resulting in a decrease in the vehicle’s recline moment.
When going over large hills or crater-like bumps on a track, the back wheel of the vehicle is often able to clear bumps, keeping the problem from a leaf-spring car hindering enjoyment.
- Easy to Install and Modify
As we discussed the leaf spring design has an assembly of steel sheets held together just with simple mounting hardware. This lets you easily remove and replace leaf spring leaves, or modify their stiffness.
Thereafter, the alteration of leaf springs is quicker and simpler. While the simple assembly process is advantageous, it is worth noting that the leaves can be replaced and added to the spring to alter the deflection.
It is also possible to increase or decrease the leaf load by changing the leaves or removing them, which will absorb or discharge the road imbalance by varying the degree of the spring.
- Better Control and Reliability
The damping ability of an automobile’s suspension is highly critical. A vehicle with a worn-out damping mechanism will tend to move around violently when going over any bumps or holes in the road. This became a major issue as early as the beginning of the 20th century, with the advent of the car suspension that had helical springs.
Leaf spring technology was able to better control the vehicle’s movement using friction between the plates of steel. This produced a delay in response to the vehicle’s sudden drooping, consequently allowing for a much more controlled ride.
- Incredible Load Capacity
Leaf springs are composed of extremely thick metals organized in several layers, making this suspension system ideal for supporting the physical elements of the automobile. At the same time, due to their tremendous tensile strength, leaf springs are capable of taking massive vertical loads.
Vertical loading is distributed equally throughout the spring-suspension mechanism as opposed to concentrating right down to a smaller placement that can not assist this ability. Because of their robustness and higher load capacity, they continue to be used in industries that demand strenuous long-term use.
- Cost-efficient
Leaf springs are far less costly to make and mount than other suspension systems. This is because they do not often need the specialized mounts, cables, and other hardware that are necessary with three- or four-link rear suspensions. This way leaf springs stay dependable while also remaining cost-effective.
Disadvantages Of Leaf Spring
The earlier that you install what is today known as the leaf spring in your truck, the easier it’s going to be to adopt it. However, there are a few downsides to present-day leaf springs you should know more about in advance. Here are some of them.
- Prone to Lose Shape
The steel leaf springs tend to undergo a lot of wear and develop a shape that is lower than the manufacturer’s specifications, so the automobile gradually loses ride height. Sag between the two springs creates asymmetric biting or wedge or cross weight in the car, affecting steering.
Some experts will frequently determine repairs to fix the difference in sag between adjacent leaf-shaped springs. Sagging also has an effect on rear-wheel steering, which puts different stress on the springs.
- Inefficient Suspension Tuning
Leaf spring suspensions generally aren’t ideal for suspension tuning. For racing cars and other motorsports applications, having the ability to adjust a setup for different driving conditions is a reality that is much more easily achieved through coilover suspensions.
Since leaf spring suspensions can only really be adjusted using the balancing act between the leaf springs and the chassis they are attached to, they are severely limited in their ability to change the length of the leaf stems. This is why, you have the only option to adjust the strength and flexibility of the leaf springs setup.
- Low Range of Motion
When leaf springs rub against the chassis or axle, they can provide a very limited range of motion, whereas a spring and damper configuration enables much more freedom of movement.
Leaf springs are firmly clamped to one another and affixed to the chassis as well as the axle, so they do not allow any degree of freedom other than up and down. This produces considerable stress on parts that tie the setup together which results in frequent wear and tear.
- Less Cornering Efficiency
The leaf spring suspension associated with the rear axle has the potential to produce unusual swerves when driving an old Mustang, a trait characteristic of the brand. This is because the rear axle will only bounce around at high-speed corners, as the sway bar and axle are forced to move together when a newer dampened setup would dwarf this outcome greatly.
- Stiff Ride
A leaf spring does not supply the same comfort as a helical spring due to the tighter construction and clamp they are bolted to. This along with a lack of popularity is why the use of leaf springs in cars was almost eliminated after the introduction of an efficient damping mechanism in the 1970s.
Final Words
Given that the leaf spring remains the predominant suspension choice for commercial trucks, you’ll have to travel back to the 1960s to find cars with that kind of suspension – a Corvette was prohibitively expensive, of course.
From its stilt-like structure to a Ford Mustang GT, the leaf spring has had its moment in vehicle suspension, but despite its simple design, the time for this suspension has passed. Still, if you’re willing to opt for a leaf spring setup, weigh the advantages and disadvantages of leaf spring on your own. Hope this will give you the right direction.
