Leaf Springs

Common signs are a trailer that sags or sits unevenly, a harsh or bouncy ride, or clunking over bumps. Look for cracked or broken leaves, springs that have gone flat, or heavy rust and flaking — especially on a boat trailer that lives in salt water. A cracked or broken leaf, or springs that aren't securely mounted, will also fail a WoF. If in doubt, it's an easy thing to have checked.

Double-eye springs have a rolled eye at both ends that mount on shackles and hangers, so the spring is fixed at both ends — common on tandem and heavier trailers. Slipper springs have an eye at the front and a flat, tapered "slipper" end at the rear that simply slides on a rear hanger, which makes them simpler and cheaper — common on smaller single-axle and boat trailers. Trojan make both, so the easiest approach is to match whatever your trailer is set up for now.

Multi-leaf springs use several stacked leaves and are the traditional, tough, load-carrying option. Taper-leaf springs use fewer leaves that are tapered in thickness, which gives a smoother ride and less inter-leaf rust and wear — a nice upgrade for boat trailers. Both come in a range of capacities; it mostly comes down to ride quality versus budget. If you're not sure, we can talk you through the Trojan options for your trailer.

Both are good; they suit different priorities. Leaf springs are simpler, cheaper and easy to repair or re-rate by changing the spring pack — a proven, budget-friendly choice. A Trojan Duratorque is a rubber torsion axle that springs each wheel independently, giving a smoother ride, built-in damping and almost no maintenance (nothing to rust or crack), which is why they're so popular on boat trailers. If you're rebuilding or upgrading and want the smoothest, lowest-maintenance option, a Duratorque is worth a look; if you want simple and economical, stick with leaf springs.

Match the springs to your trailer's axle rating and its fully loaded weight — Trojan springs are sold by capacity per pair (commonly 500kg, 1000kg, 1500kg and up). Don't under-rate them: the springs need to comfortably carry the trailer plus its heaviest load, with a bit in hand. If you know your trailer's rating or the weight it carries, we'll match the right spring; if not, bring the old spring in and we'll go from there.

Beyond capacity, match the physical size: the spring length (eye-to-eye or overall), the eye diameter, the width, and the number of leaves. Slipper and double-eye springs aren't interchangeable, so note which your trailer uses. The simplest way to get it exactly right is to bring your old spring in or measure it and count the leaves — we'll match it to the correct Trojan part.

It's strongly recommended. Boat trailers get reversed into salt water regularly, which eats ordinary painted springs quickly. Trojan's galvanised and coated springs stand up to that far better and last much longer, so they're well worth it for anything that sees the sea. Whatever springs you run, giving the trailer a fresh-water rinse after each launch will get you a lot more life out of them.

Yes — always replace springs as a matched pair across an axle, so the trailer sits level and tows evenly. If one side has worn or broken, the other usually isn't far behind. On a tandem trailer it's worth doing all four together. Trojan spring kits are sold per pair with the fittings included, which makes a matched replacement easy.

Yes. Trailers need a WoF, and the suspension is part of it — springs must be secure, correctly mounted and free of cracked or broken leaves, and the suspension must be in sound condition and suited to the load the trailer carries. This is a guide rather than the final word, so if you're unsure whether your springs will pass, have a WoF inspector take a look.

For most trailers it's a manageable DIY job with basic tools. Support the trailer securely on stands with the load off the springs, undo the U-bolts and shackles, swap the spring, fit new bushes, and tighten everything back up properly. Take care supporting the trailer safely and make sure the U-bolts are done up tight. If you'd rather not, any trailer or towbar shop can do it — we can supply all the Trojan parts either way.