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What Are Parabolic Leaf Springs?
Parabolic leaf springs use fewer, thicker leaves with a tapered profile. Each leaf is designed to flex independently and is separated by spacers to reduce friction. This design results in a lighter spring that allows more controlled movement and delivers a smoother ride.
They are well suited to off-road trailers and applications where comfort and reduced unsprung weight are priorities, such as camper or expedition builds.
What Are Conventional Leaf Springs?
Conventional springs use multiple flat steel leaves stacked together in decreasing lengths. The leaves are in direct contact with one another, which adds friction and stiffness when loaded.
This proven design offers exceptional strength and durability, making it the preferred choice for heavy-duty work trailers, agricultural equipment and commercial transport applications.
Advantages of Parabolic Springs
Parabolic springs provide a smoother ride on both sealed and unsealed roads. Their lighter weight reduces strain on other suspension components, while the reduced friction between leaves allows better axle articulation over uneven ground.
For trailers carrying delicate cargo or operating in off-road conditions, parabolic springs can improve comfort, control and overall handling.
Advantages of Conventional Springs
Conventional leaf springs remain the strongest option when maximum load capacity is required. The layered design spreads weight across multiple leaves, giving them greater resistance to sagging and deformation under heavy loads.
They are widely available, straightforward to source and capable of withstanding continuous commercial use with minimal upkeep.
Choosing the Right Spring for Your Trailer
If your trailer regularly operates close to its Gross Vehicle Mass (GVM), conventional springs are generally the best option for long-term durability. If ride comfort, weight reduction and improved suspension movement are more important, parabolic springs are worth considering, provided they are rated appropriately for the load.
Whichever type you select, match your spring kit to the trailer’s axle configuration. Explore our single axle spring kits, tandem axle kits and tri-axle kits to find the right fit for your setup.
Where to Buy Trailer Leaf Springs
Treadway offers a comprehensive selection of leaf springs and complete spring sets to suit both parabolic and conventional designs. Our suspension products are engineered for New Zealand conditions and supported by decades of industry experience.