Trailer Leaf Spring Identification, Measurements, and Replacement Guide

🛒 Shop These Parts at AAA Trailer

Dexter 4-Leaf Double Eye Spring — 1,750 lb, 25-1/8"Replacement spring for 3,500 lb axlesShop Now →Brass Leaf Spring BushingBest-selling bushing replacement — 16 sold last 90 daysShop Now →9/16" Nylon Leaf Spring Bushing — 1.75" WideNylon bushing for standard utility trailer springsShop Now →9/16" x 3-1/2" Greaseable Wet Shackle BoltGreased shackle bolt — reduces spring bushing wearShop Now →Shackle Link Straps — Heavy DutyBest-selling suspension hardware — 19 sold last 90 daysShop Now →TruRyde Greaseable Shackle Bolt Kit — FA-7-187Step-down wet bolt — #1 best-selling axle part, 27 soldShop Now →

🔩

Quick Answer

Trailer leaf springs are identified by three measurements: overall length (eye-to-eye), width (typically 1-3/4" for utility trailers), and capacity (which correlates to the number of leaves). Eye type (double eye vs. slipper) and leaf count also matter when ordering. The spring capacity should be at or above the axle's per-spring rating — a 3,500 lb axle uses two springs rated at 1,750 lb each.

How Leaf Springs Are Measured

Measurement	Where to Measure	Common Values
Overall Length	Eye bolt center to eye bolt center (or center to tip for slipper end)	24", 25-1/8", 25-1/4", 26", 29", 32"
Width	Across the spring leaves at the widest point	1-3/4" (utility trailers), 2" (heavier trailers)
Capacity	Stamped on the main leaf or from count — more leaves = higher capacity	1,000 lb, 1,750 lb, 3,000 lb per spring
Leaf Count	Count the metal leaves in the pack	2–4 leaves for most utility trailers

Double Eye vs. Slipper — What's the Difference?

Double Eye

Circular eye bolt at both ends
Both ends use shackle bolts and bushings
Most common on utility and cargo trailers
More secure — both ends fully captured

Slipper (Single Eye)

Eye bolt at front, flat "slipper" end at rear
Rear end slides in a bracket as spring flexes
Common on larger tandem-axle trailers
Simpler to replace — rear end just slides out

Spring Capacity by Axle — Quick Reference

Axle Capacity	Per-Spring Rating Needed	Typical Leaf Count
2,000 lb	1,000 lb per spring	2 leaves
3,500 lb	1,750 lb per spring	3–4 leaves, 25-1/8" to 25-1/4" long
5,200–6,000 lb	2,600–3,000 lb per spring	4–5 leaves
7,000 lb	3,500 lb per spring	5–6 leaves

Signs a Leaf Spring Needs Replacement

Broken main leaf — visible crack or separation in the top (widest) leaf. Replace immediately — do not tow.
Sagging ride height — trailer sits noticeably lower on one side, or the tongue angle has changed. Spring has lost its arch under load.
Metal-on-metal clunking — spring leaves contacting each other directly, worn inter-leaf clips
Visible cracks — especially near the center bolt or eye bolts, which are high-stress points
Heavy rust through the leaves — surface rust is normal; rust that has eaten through leaf thickness is not

The Bushings and Bolts — Replace These First

Before replacing a full spring, check the bushings and shackle bolts — these wear items fail far more often than the springs themselves and cause most of the clunking, play, and uneven ride you'll feel. Replacing worn bushings is a 20-minute job per corner; replacing a spring is a 45–60 minute job. Brass and nylon bushings both work; brass is more durable and is the best-seller at AAA Trailer. Greaseable wet bolts (shackle bolts with a grease zerk) dramatically extend bushing life on trailers that get regular use.

Frequently Asked Questions

My trailer bounces badly even when lightly loaded. Is it the springs?

More likely worn or missing bushing inserts, or loose shackle bolts. Springs that are broken or completely flat cause sagging, not excessive bounce. Check bushing condition first — worn bushings allow the spring to rattle in its mounts, creating a bouncy, rough ride. Replacing bushings and tightening shackle bolts often resolves this without touching the springs.

Should I replace springs in pairs?

Yes. If one spring on an axle has failed or sagged, the other side has been carrying extra load and is likely close behind. Replacing both springs at once keeps the axle balanced and ride height even. Mixing a new spring with an old sagged spring on the same axle creates an unlevel trailer and uneven tire wear.

Can I use a higher-capacity spring on my axle?

A spring rated above the axle's per-spring requirement is fine — the extra capacity gives you more margin. A spring rated below the axle's requirement will sag and fail prematurely. Never downgrade spring capacity. Match or exceed the axle's rated per-spring load.

⚠ Still Not Sure What You Need?

Call AAA Trailer at (517) 225-1991 with your spring length, width, and axle capacity (from the bolt pattern or bearing numbers). We'll confirm the right spring and bushing kit for your trailer.