Estimated Weight rating for 1-1/2-Inch Square Trailer Axle

Question:

have single axle trailer 6x9 custom fabricated - very old - diamond plate bed calculated trailer only weight supported by springs - 900 lb axle - 1.5inch bent, solid bar, 4inch axle existing springs - 29.5inch cc eyes/1 3/4Wide/4 leaves incl double eye leaf/1/4inch leaf thickness/ 9/16 shackle bolts seems very lightly sprung - my leaning weight over a tire will lower the rail 1 to 1.5 when evenly loaded have put 1200 lb load in this trailer one side is consistently considerably lower than other - reason for wanting to respring cannot locate any info about or similar new for sale on this type axle - appears to be just no longer available - do you have any clue of what the rating of this axle might have been?? any idea based on the above info of what makes sense for a replacement spring capacity per side and what you might have that would work?? Thank you

asked by: David J

Expert Reply:

Trailer axles will often have some kind of labeling on them to indicate their weight capacity, sometimes a sticker but sometimes a metal plate too. If very old that axle sticker or plate could be long gone.

The 1-1/2-inch square axle we offer, CE Smith Trailer Axle # CE33201GA-HUB, is rated for 1800-lbs and includes 5-on-4-1/2 idler hubs and also comes with bearings, races, seals, grease caps, wheel studs, lug nuts, and marine-grade wheel bearing grease. This axle has a hub face spacing of 57-1/2-inches and a spring center spacing of 46-1/2-inches. I think it is safe to say that your axle is rated for no more than this one, or at most 2000-lbs.

Leaf springs that are very old and well-used can elongate or stretch by up to 3/4-inch. But the longest one we offer is 27-inches eye-to-eye, part # SP-210275, which is 4-leaf and rated for 3500-lb axles so it would be too stiff for your application. All double-eye springs are linked for you. The spring we have for 2000-lb axles, part # SP-124275, measures 26-inches eye to eye.

If you measured the spring while it was installed on the trailer you will want to remove it and re-measure when it is not under tension. This will give you a more accurate length.

You may care to review the linked article on trailer suspensions.

expert reply by: Adam R