Nov 13, 2023
Leaf Springs Vs. Coil Springs Vs. Air Springs: What’s Best For Your Truck?
Throughout the 100-year history of pickup trucks, the suspension system has
Throughout the 100-year history of pickup trucks, the suspension system has seldom received the attention and praise it deserves. Not today! After all, a truck's suspension is the primary reason it can haul and tow, but at the same exact time it's also the reason you experience sufficient ride quality in the cab. In recent decades, coil spring suspension systems have infiltrated the truck segment, challenging the dominance of leaf spring configurations. Within that same window of time, we’ve seen air spring technology become commonplace—in the form of being a suspension aid for improved stability and even replacing a truck's leafs or coils entirely.
So which type of suspension is right for you and your truck, leaf, coil or air? The ultimate decision on that is yours, but we’ll help differentiate between the three and spell out the key advantages and disadvantages of each system. Whether you’re looking to upgrade your late-model truck or you’re building an off-roader from the ground-up, each suspension type has its place and purpose. Here's why.
Leaf spring suspension was around long before the first automobile was produced and there are good reasons for it: leaf springs are simple, reliable and highly effective at stabilizing and handling weight. They’re highly advantageous in load-bearing applications due to their ability to spread the load of the vehicle over a broad area.
Leaf springs work by flattening out over bumps from the road or terrain in order to dampen inputs. From a durability standpoint alone, leaf springs are hard to beat. Aside from shackle bushings, which eventually require replacement, leaf springs can last the life of a vehicle.
No suspension system is perfect or without its faults, and ride quality has long been the biggest drawback associated with leaf springs. The words rough ride and leaf springs go hand-in-hand, especially when they’re employed under the front-end of a truck. As for the rear suspension, which is almost exclusively leaf springs on pickup trucks, a jarring, bouncy ride is common when empty—especially in heavy-duty, dual rear wheel applications with huge payload capacities. Leaf springs are attached to fixed locations on the truck's chassis. This leaves little room for adjustments and/or customization of the vehicle's suspension geometry. Additionally, leaf springs allow for very limited departure and approach angles and are also prone to succumbing to axle wrap, where they tend to twist into an "S" shape.
For superior ride quality, especially from the front suspension system, coil springs are the way to go. One big reason for this is that each wheel experiences the conditions of the road (and/or terrain) separately from the other. For off-road agility, coil springs are also often the best choice. This is because coil springs allow considerably more movement in the suspension system than leaf springs. Another big benefit exists in your ability to choose from progressive, linear or dual rate spring rates, which makes it possible to fully customize and fine-tune your ride quality and performance. Lastly, the weight savings in opting for coil springs over leaf spring sets is often significant.
The list of negatives associated with coil springs isn't long, but there are certain applications where they don't make the most sense or simply aren't cost-effective. In heavy-duty applications, they aren't as stable for load carrying tasks as leaf springs. Having said that, Ram has offered a rear coil spring system option on its 2500 model trucks since ’14 with some success. However, Ram remains an outlier here, with neither Ford or GM having tried anything like it on their ¾-ton and larger trucks. One of the biggest drawbacks for coil spring suspension systems lies in their costs, as they (along with their supporting parts) can run significantly higher than traditional leaf springs.
Air springs are a unique suspension solution for many truck enthusiasts. For one, they can be used to help stabilize, level and optimize a truck's factory suspension system. And for another, they can be used as the sole means of suspension—most notably offering ride height adjustability. In the former application, they can make a world of difference on a truck that experiences rear suspension sag when towing or hauling, working to improve both the truck's overall performance and safety. In custom applications, laying frame or clearing larger wheels and tires is made possible through the use of air springs.
While leaf springs and coil springs can lose some of their strength with age and use, a failure with either one of those systems is arguably not as devastating as one that occurs on a truck that's dependent on air spring suspension. The rubber, tire-like construction of air springs can degrade over time, but air lines and fittings are the biggest weak links. An air leak poses a major problem in these systems and can effectively sideline your truck. Additionally, a truck that's completely dependent on a functioning air compressor could be out of commission if it dies. Our advice for air springs, be it for helper springs or in a dedicated air-ride system: always include a Schrader valve (or two) so you can manually inflate the system if your onboard compressor fails.
There is a reason leaf springs have remained the rear suspension system of choice for OEM truck makers. They work. While ride quality is often adequate at best when empty, a 1-ton or larger pickup boasting a 3-ton payload capacity rides like a Cadillac when laden. Without a doubt, leaf springs are highly cost-effective for OEM's, but their stability and simplicity will continue to make them a mainstay in pickup trucks for the foreseeable future.
The ability to adjust and fine-tune ride height on the fly or to your specific comfort preferences has made air spring suspension systems immensely popular over the years, especially in custom truck builds. One of the best-executed examples we can think of from recent years is the LokJaw ’66 C20 project from Banks Power. By using Ridetech's RidePRO E5 air ride suspension control system, complete with dual 150-psi air compressors, an aluminum 5-gallon air tank, a BigRed Air Valve Block with 3/8-inch ports and eight independent solenoids, the ride height at each corner can be configured separately. Banks’ creation is a truck, equipped with an air spring system, that brings new meaning to the term "laying frame."