How Much Upward Bend Should Trailer Axle Have

Question:

How much of a bend upward should an axle have? I used a 4 foot level and centered it on the bottom of my axle. On my front I could put a 13/64 drill bit in the arch but on the rear I can put a 3/8. I ask this because the back seems a little too bowed up and has put a dent in the frame in the center.

asked by: Timothy K

Expert Reply:

While trailer axles do feature an upward bend like you are describing, there isn't a particular amount/measurement that is standard across the board. This bend in the axle is designed so that it will straighten under a trailer's loaded capacity. While I can't really say for sure if the bend you measured at the rear on your trailer is normal or not, the damage that it is causing to the frame is certainly cause for concern. This either indicates that there is indeed too much of a bend or maybe something else going on with the trailer's suspension that would have caused it to be this way. Another possibility is that the axle is over-rated for the trailer, which might result in the trailer's load not being enough to straighten out the bow.

My best recommendation would be to simply bring the trailer up to a local shop to have them take a look at all of the suspension components. It may be that the axle needs to be replaced, but I would just make sure that there isn't another underlying issue going on first so that it doesn't happen again.

I have attached a link that will take you to our available selection of trailer axles that you can look through if needed.

expert reply by: Chris R

Don L.

11/3/2021

I bought a brand new, square 1-1/2" axle: "2000-Lb. Capacity Spring Trailer Axle with Adjustable Spring Mounts — 59 1/2in. Hubface, 43in.–49in. Spring Center, 64 1/2in.L, Straight". After reading your articles, I went and looked for a bow for top or bottom, it has none. I used a straight 4' level. All 4 sides are perfectly flat, no bow on any side, whatsoever. Is this OK, or should I return it and buy a different one? Old axle was starting to sag and wear tires after 20+ years. Also, how much side to side play should I have where my springs are bolted to my trailer? Currently I have right at a 1/16" gap at all 3 bolt locations, each side. While axle is removed, I could unbolt and shim with a washer if current gap is too wide. What do you suggest?