Why did they stop using leaf springs?
Leaf springs largely disappeared from the front lines of passenger-car suspensions, replaced by coil springs and independent designs that offer smoother rides and better handling. They remain common in certain heavy-duty and commercial applications where payload and rugged durability matter.
Leaf springs were once the backbone of automotive suspensions due to their simplicity and robustness, but advances in suspension design, materials, and manufacturing allowed coil and multi-link systems to deliver superior ride quality, handling, and packaging. This article examines why the shift happened, and where leaf springs still fit in today.
A Brief History of Leaf Springs
Leaf springs originated in the early days of wheeled transportation and became a de facto standard in automotive design by the mid-20th century. A stack of curved, flexible leaves arranged to support the axle provided a simple, durable way to manage load, control wheel movement, and locate the axle. Over decades, they helped keep cars affordable and reliable as mass production and highway speeds grew.
In passenger cars, leaf springs offered a straightforward solution for both front and rear suspensions, but as automakers pursued smoother ride, sharper handling, and lower vehicle heights, coil springs and independent layouts gained traction. Today, leaf springs are far less common in new passenger cars, though they persist in certain niches and markets.
Today, leaf springs remain in use in several sectors where the requirements differ from mainstream passenger-car design, including heavy-duty trucking, commercial vehicles, trailers, and some rail applications. In these areas, the benefits of durability and load-handling can outweigh the ride premium of alternative suspensions.
Legacy in heavy-duty and commercial sectors
In heavy-duty and commercial contexts, leaf springs are valued for their ruggedness, ease of inspection, and predictable load distribution. They handle constant high loads well and are relatively straightforward to repair in field conditions, which matters in trucking yards, remote sites, and on long-haul routes.
Reasons for the Shift
As vehicle design evolved toward higher performance, better comfort, and more flexible packaging, automakers increasingly turned away from leaf springs in favor of coil-based and multi-link suspensions. The shift was driven by several intertwined factors:
- Lower unsprung weight improves ride quality and wheel control, which is easier to achieve with coil springs and independent geometries.
- Independent suspension reduces body roll and enhances handling by allowing each wheel to move more freely, something leaf-sprung axles struggle to emulate.
- Packaging and safety demands require lower floors, crumple zones, and space for crumple zones; coil and multi-link designs offer more flexible underbody layouts.
- Weight and fuel efficiency: lighter or better-mass-optimized suspensions can reduce overall vehicle weight and improve efficiency, even when payload handling is preserved.
- Manufacturing and maintenance efficiency: modern coil/multi-link damped systems can be produced at scale and can simplify assembly, calibration, and replacement in many markets.
- Advances in materials and damping technology: progress in high-strength steels, progressive-rate springs, air springs, and electronically controlled dampers expanded design options beyond traditional leaf packs.
Notably, leaf springs still offer advantages in certain contexts, such as simple, robust payload management and straightforward field repair, which keeps them in use for specific heavy-duty, commercial, and rail applications.
What remains in use
While passenger cars have largely shifted away from leaf springs, they persist in several domains where demands differ:
- Heavy-duty trucks and commercial vehicles that require strong load-carrying capability and straightforward maintenance
- Trailer axles and some off-road vehicles that prioritize durability and predictable load behavior
- Railway freight cars and certain industrial applications where rugged, simple suspension is advantageous
For most consumer-oriented automobiles, the trend continues toward coil-sprung, multi-link, and, increasingly, air- or magnetorheological-damped suspensions designed to deliver better ride, handling, and efficiency.
Summary
Leaf springs were once ubiquitous because they were simple and durable. Over time, engineers moved toward coil springs and independent suspensions to improve ride comfort, handling, and packaging, especially in passenger cars and light-duty vehicles. Leaf springs remain important in heavy-duty, commercial, and rail contexts where payload, durability, and repairability take precedence, illustrating how a technology can fade from general use while continuing to serve specific, demanding applications.
