A replacement leaf spring has to fit your hangers and carry the same load as the one it replaces. Measure the old spring properly and the new one bolts straight in. Guess, and you’ll find out at the hanger bolt.
Signs your springs need replacing
A cracked or broken leaf
Springs that have gone flat and lost their arch, so the trailer sits low
Leaves that have shifted out of line
Worn or missing eye bushings
Heavy rust and pitting, common on boat trailers
Uneven tire wear or a trailer that doesn’t track straight
Step 1: Identify the spring type
There are two common types, and they are not interchangeable without changing hangers.
Double-eye: a rolled eye at both ends. Each eye bolts into a hanger or shackle. Most common on single-axle and lighter trailers.
Slipper: an eye at one end only. The other end is flat and slides in a hanger. Common on heavier and tandem-axle trailers.
Step 2: Measure the length
For a double-eye spring, measure from the center of one eye to the center of the other. For a slipper spring, measure from the center of the eye to the end of the flat slipper.
Measure with the spring off the trailer if you can. A spring flattens under load, so measuring it installed gives you a longer number than the part number is based on. As a rough guide, a common 3,500 lb double-eye spring is about 25 inches eye to eye.
Step 3: Count the leaves and check the capacity
Each spring carries half of the axle’s load, so a 3,500 lb axle uses two springs rated for about 1,750 lb each. More leaves usually means more capacity.
Axle capacity | Rating per spring |
|---|---|
2,000 lb | About 1,000 lb |
3,500 lb | About 1,750 lb |
5,200 lb | About 2,600 lb |
7,000 lb | About 3,500 lb |
Good to know
Don’t add capacity with stiffer springs alone. Your axle, tires and frame set the real limit, so match the capacity you have.
Step 4: Measure the width and the eyes
Measure the width of the leaves, usually 1-3/4 or 2 inches. Then measure the inside of the eye and note the bushing type: nylon or bronze. The bolt size has to match your hangers.
Step 5: Check the hangers, shackles and bolts
While the spring is out, look at the hardware. Worn shackle bolts and bushings cause play and noise, and on tandem trailers the equalizer between the axles wears too. Replacing the hardware with the springs is cheap and saves doing the job twice.
Shop tip
Always replace springs in pairs on an axle. On a tandem trailer, replacing all four keeps the ride height level.
What to bring to the store
Spring type: double-eye or slipper
Length, measured as above
Number of leaves and the leaf width
Eye size and bushing type
Axle capacity from the tag
A photo of the spring installed and of the hangers
Get the part or the repair
Shop online for local pickup, or bring the old part to our Port St. Lucie store at 496 SW Voltair Terrace and we’ll help you match it. Not comfortable doing the job yourself? Request a repair and we’ll take care of it, or call us on 772-924-7299.
Guides are general advice. Trailers vary, so check your trailer’s labels and manuals, or ask us before you order.
