How to Measure Trailer Leaf Spring to Find Correct Replacement


How do I measure the length of utility trailer springs, straight across or along the curve? The ones on there now measure 32 1/2 inch along the curvature from the center of one bolt hole to the center of the other bolt hole.


Helpful Expert Reply:

To correctly measure a leaf spring, you'll want to jack the trailer up on jack stands so the axle is hanging freely, then measure directly across from the center of one spring eye to the other, as shown in the provided diagram. The height of the spring and the distance from the spring eye to the center of the spring can also be helpful in finding the correct replacement.

To ensure you're getting the correct leaf springs, you'll also need to know the capacity of your axle. If you can find that information on the axle itself, we can make a pretty good guesstimate if you can provide as much as the following information as possible:

Axle diameter (or circumference divided by 3.14)

If the axle is 1 to 1-1/2 inches in diameter, it's likely a 1000 lb axle
2-3/8 in diameter, 3500 lb axle
3 inches in diameter, 6000-7200 lb axle
3-1/2 inches, 8000 lb axle
4 inches, 9000 axle
5 or more, 10000 lb axle

Knowing the wheel bearing reference numbers or the wheel's bolt pattern will also be a good clue to the axle capacity.

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helpful expert reply by:
Mike L

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Follow up Questions

Tim K.

I've done measurements. 25 from eye to eye. 1and 3/4. Wide 8 lugs 7 springs. It's a 40fr toy hauler Any suggestions would be greatly appreciated. No one and here has anything like that 95823

Reply from Chris R.

We do have some leaf springs available that closely match the length you measured. It's important to keep in mind that leaf springs will stretch a bit over time, so you're likely wanting a new set that's just a little shorter in length. A 24-7/8" long set like # SP-222275 , which is designed for 5,300 pound axles, would work great. If you can tell me what capacity your axles are I will be happy to verify this will work or suggest an alternate replacement. 70811

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