How to Measure a Trailer Leaf Spring — 6 Measurements to Find the Right Replacement

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Quick Answer

Six measurements uniquely identify any trailer leaf spring: eye-to-eye length, number of leaves, leaf width, eye type, center bolt hole diameter, and leaf capacity (if stamped). Write all six down before you call or order. A spring that matches on length but differs in width, leaf count, or eye type will not work. With those six numbers, we can find the right spring in under a minute.

Your Spring Measurement Worksheet

Take these six measurements with a steel tape measure. Write them here before calling or ordering online.

Leaf Spring Measurement Worksheet

Fill in all 6 before ordering

Eye-to-Eye LengthCenter of front eye to center of rear eye (or tip for slipper)

inches

_ _ _ . _ "

Number of LeavesCount every metal leaf in the pack, including the main leaf

leaves

_ _

Width of Main LeafMeasure across the top (widest) leaf — do not include clips

inches

_ - _ / _ "

Eye Type (Both Ends)Double eye, slipper/radius end, hook end, open eye — see diagrams below

type

________

Center Bolt Hole DiameterThe bolt hole through all leaves at the center of the pack — use a drill bit to gauge

inches

_ /_ _"

Capacity StampCheck for a number stamped into the main leaf near the center — example: 1750, 3000

lbs

_ _ _ _

Measurement 1 — Eye-to-Eye Length

This is the most important measurement. Measure center-to-center of the two eye bolt holes when the spring is installed on the axle — or remove it and measure on a flat surface.

Eye-to-Eye Length — center to center

Not overall length of the spring — measure center of eye hole to center of eye hole

For slipper springs: Measure from the center of the front eye bolt hole to the flat tip (not the end of the metal — just the finished tip of the last leaf). Common slipper tip lengths are measured differently than eye lengths — confirm with us at AAA Trailer if unsure.

Pro Tip — Measuring on a Worn Spring

If the spring has sagged badly or is broken, measure the installed spring from center bolt to center of each hanger bolt hole instead — this gives you the effective installed length, which is what the replacement needs to match to fit the hangers without shimming.

Measurement 2 — Number of Leaves

Count every individual metal leaf (also called a "plate") in the pack — from the widest main leaf on top down to the shortest bottom leaf. Include the main leaf in your count. Leaf count directly correlates to capacity: more leaves means a higher-rated spring in the same length and width family.

Leaf Count	Approximate Capacity (1-3/4" wide)	Typical Axle
2 leaves	500–750 lb per spring	1,000–1,500 lb axle
3 leaves	1,000–1,500 lb per spring	2,000–3,000 lb axle
4 leaves	1,750–2,500 lb per spring	3,500–5,000 lb axle
5 leaves	3,000–3,500 lb per spring	6,000–7,000 lb axle
6 leaves	3,000–4,500 lb per spring	6,000–8,000 lb axle (heavier)

Note: capacity also depends on leaf width. A 4-leaf, 2"-wide spring has higher capacity than a 4-leaf, 1-3/4"-wide spring of the same length. Width and leaf count work together — you need both.

Measurement 3 — Leaf Width

Measure straight across the widest leaf (the main leaf on top) at its widest point. Measure the bare metal — don't include anti-rattle clips or wrap material. Almost all utility and dump trailer springs are one of two widths:

1-3/4"

Standard Width

Single axle utility trailers, most 3,500–5,000 lb axle trailers, most Dexter and Lippert axles

Heavy Duty Width

Tandem axle trailers, 5,000–8,000 lb axles, dump trailers, equipment haulers, slipper spring configurations

Width Mismatch = Wrong Spring

A 1-3/4" spring will not fit correctly in a 2" center bolt hole and U-bolt plate. A 2" spring won't fit the narrower U-bolt kit. Width determines what hardware fits — shackle bolt bushings, U-bolt tie plates, and center bolts are all sized to either 1-3/4" or 2". Always confirm width matches your existing hardware.

Measurement 4 — Eye Type

The eye is the circular or shaped end of the spring that connects to the hanger or shackle. Identify which type you have at each end — the front and rear ends can be different types on slipper spring setups.

Double Eye

Circular bolt hole at both front and rear
Both ends use shackle bolts and bushings
Most common on single-axle utility trailers
Easiest to replace — direct swap

Slipper / Radius End

Eye at front, flat or curved sliding end at rear
Rear end slides in a bracket as spring flexes
Common on tandem-axle trailers and heavier setups
Front eye mounts fixed; rear end floats

Hook End / Open Eye

Open C-shaped hook instead of a closed eye at rear
Hooks over a pin on the equalizer or bracket
Common on equalizer-equipped tandem setups
Must match the bracket pin diameter exactly

Measurement 5 — Center Bolt Hole Diameter

The center bolt passes through all leaves at the midpoint of the spring pack and holds the pack together. Its hole diameter must match the U-bolt tie plate and the replacement spring's center hole. The two common sizes are:

1/2" center bolt hole — standard on most 1-3/4"-wide utility trailer springs (3,500 lb and lighter)
9/16" center bolt hole — common on heavier springs, 2"-wide springs, and many 5,200 lb+ setups

To measure: use a drill bit as a gauge — find the largest bit that passes through the hole cleanly without play. Or use calipers if available.

Measurement 6 — Capacity Stamp

Look at the main leaf (the widest leaf on top) near the center bolt area. Many springs have a capacity number stamped directly into the metal — examples: 1750, 2000, 3000. This is the capacity in pounds per spring, not per axle. If you find a stamp, note it — it's the most direct spec available.

If there's no stamp, estimate from leaf count and width using the table in Measurement 2 above. It won't be exact, but it gets you in the right range to order with confidence.

AAA Trailer In-Stock Spring Reference

Once you have your measurements, use this table to find the matching spring in our current inventory:

Eye-to-Eye	Leaves	Width	Capacity	Eye Type	Fits Axle
25-1/4"	4	1-3/4"	1,750 lb	Double Eye	3,500 lb
26"	4	1-3/4"	2,000 lb	Double Eye	4,000 lb
27"	4	1-3/4"	2,100 lb	Double Eye	4,000–4,200 lb
25-1/4"	4	1-3/4"	2,500 lb	Double Eye	5,000 lb
25-1/8"	4	1-3/4"	3,000 lb	Double Eye	6,000 lb
27"	6	1-3/4"	3,000 lb	Double Eye	6,000 lb
25-1/4"	6	1-3/4"	3,500 lb	Double Eye	7,000 lb
26-1/2"	5	2"	3,500 lb	Slipper/Hook	7,000 lb tandem
26-15/16"	5	2"	3,400 lb	Slipper/Hook	6,800 lb tandem

Not Listed? Call Us.

We carry springs not listed here and can source many more. Call (517) 225-1991 with your 6 measurements and we'll identify the right spring or order it for you. Have your measurements written down before you call — it turns a 10-minute conversation into a 60-second one.

Always Replace the Bushings When Replacing a Spring

When you're replacing a spring, replace the eye bolt bushings at the same time. Worn bushings are what cause most of the clunking, looseness, and uneven ride that signals a spring problem in the first place. New spring + worn bushings = new spring that rides like an old one. The cost of two brass bushings is negligible compared to the labor already invested in the spring swap.

Frequently Asked Questions

My spring is 25-1/4" but the catalog also shows 25-1/8". Will either work?

Not interchangeably. A 1/8" difference in eye-to-eye length changes where the axle sits under the trailer. On a single axle trailer this is usually not critical, but on a tandem axle it affects axle alignment significantly. Order the correct length. If you're between sizes, measure again — trailer spring lengths are made to standard increments and the measurement should match exactly.

My spring has a part number on it but I can't find it. What else can I do?

Take the 6 measurements above and call us at (517) 225-1991. The measurements cross-reference to manufacturer part numbers even when you don't have the original number. The most useful combination is eye-to-eye length + leaf count + width — those three narrow it down to one or two spring options in most cases.

Should I replace all the springs at once or just the broken one?

Replace in matched pairs — both springs on the same axle. If one spring has failed or sagged noticeably, the other has been carrying extra load and its remaining life is limited. Mixing a new spring with a sagged old spring on the same axle creates an unlevel trailer, uneven tire wear, and accelerated failure in the new spring. The cost of doing it right once is less than doing it twice.

My trailer has tandem axles. Do I replace one axle's springs at a time or all four?

Minimum: replace both springs on the affected axle as a matched pair. Ideal: replace all four if the trailer is older, as the remaining springs have experienced similar wear. If the other axle's springs show no sagging and have minimal bushing play, replacing the failed axle's pair is acceptable — but inspect the others carefully and plan to replace at the next season if they're showing age.

⚠ Ordering Without All 6 Measurements

The single most common mistake when ordering replacement springs is ordering on length alone. A 25-1/4" spring that is 2" wide with 6 leaves is a completely different part from a 25-1/4" spring that is 1-3/4" wide with 4 leaves — wrong capacity, wrong hardware, wrong spring. Take all 6 measurements before you order. Call us at (517) 225-1991 if you need help confirming the right part.