For years people have asked where to place the jack in order to jack up a travel trailer. And people always say do not put the jack under the spring pack. This has bothered me for years because it doesn't make sense to me. Now I'm not an engineer by any means. But could somebody please explain why under the spring pack is bad? I mean look at the pictures below. In an under slung axle the entire weight of the trailer looks to be on two very small u-bolts. Am I wrong? It seems that the u-bolts are holding the weight. If the thin u-bolts are holding the weight.and the spring is on a thin perch welded under the axle; How is jacking at that point going to be a problem?And in a travel trailer with over slung axles putting a block, or even a floor jack under the axle seems like it would be okay. The axle tube is thick enough to hold the trailer in the air with the u-bolts on top. Are we saying the tube is thinner on the opposite side of the axle tube?

I jack under the spring plates and have never had a problem.Bill

You're right about the U-bolts - looks pretty weak but the tensile strength of steel is actually quite high. Not to say at all that the U-bolts are overdesigned, but they could be sized properly.As to jacking there - it's not a matter of "can" it hold...it's more about "is it the safest point to jack from." It is inherently unstable jacking it up by the springs - a gust of wind could shift the loading, or one of the bolts holding the springs could fail. Jacking it directly at the frame minimizes the points of failure.It's the same reason we should use jack stands when working under a vehicle. The jack itself should hold, but why take the risk - granted, many of us, myself included, do take that risk sometimes - but it's not the safest way of doing it.

I've jacked under the spring for years, No problem.

I always jack under the spring plates and never give it a second thought.I usually use a squat bottle jack, take it up far enough to get the wheel off, done.All this hooplah about it'll bend your axel, bend your frame, wreck this wreck that.... Horse Puckey!Consider how much any RV flexes, bends, heaves and dips on the roads we drive on. It's a hundred times more than lifting an axel a couple inches.Take it to a tire store and watch how they jack it. Under the spring plates...

I'd certainly put the jack there before I would ever put it on a Lippert frame if you have one of those high quality POS's

Why not jack trailer under the spring plates? | Good Sam Community

BobsYourUncle
Nomad
Oct 02, 2022
I always jack under the spring plates and never give it a second thought.
I usually use a squat bottle jack, take it up far enough to get the wheel off, done.

All this hooplah about it'll bend your axel, bend your frame, wreck this wreck that.... Horse Puckey!

Consider how much any RV flexes, bends, heaves and dips on the roads we drive on. It's a hundred times more than lifting an axel a couple inches.

Take it to a tire store and watch how they jack it. Under the spring plates...
Tyler0215
Explorer
Oct 02, 2022
I've jacked under the spring for years, No problem.
rdhetrick
Explorer
Oct 02, 2022
You're right about the U-bolts - looks pretty weak but the tensile strength of steel is actually quite high. Not to say at all that the U-bolts are overdesigned, but they could be sized properly.

As to jacking there - it's not a matter of "can" it hold...it's more about "is it the safest point to jack from." It is inherently unstable jacking it up by the springs - a gust of wind could shift the loading, or one of the bolts holding the springs could fail. Jacking it directly at the frame minimizes the points of failure.

It's the same reason we should use jack stands when working under a vehicle. The jack itself should hold, but why take the risk - granted, many of us, myself included, do take that risk sometimes - but it's not the safest way of doing it.
Trackrig
Explorer II
Oct 02, 2022
I jack under the spring plates and have never had a problem.

Bill

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Why not jack trailer under the spring plates?

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