Jacking up fifthwheel

All the owners' manuals say that.

If you jack in the middle of the axle you will probably bend the axle since it isn't designed for that. If the builders said that it is okay to jack on the axle, and someone jacked in the middle of the axle and bent the axle, then they would holler that "The builder said it was okay to jack on the axle."

Consequently the builders put in a CYA statement that never to jack under the axle. If you ever tried to raise your trailer high enough to change a tire, you'd understand how ludicrous the idea is that you have to jack under the frame.

My Jayco owners manual states to jack only on the frame never on any part of the axle.

MFL wrote:

kaydeejay wrote:

rhagfo wrote:
..............The issue for me jacking on the frame, is that it is so high, and you need to raise about 6" to 8" to get the tire off the ground.

Not to mention what that does to torque the frame if the front legs are down!
That's why I only jack up my fiver when it's hitched to the truck; that way it can rotate if needed.
And I jack under the U-bolts.

Both good points here from Russ, and Keith. I have heard people say "you don't need to be hooked to truck, to lift side of FW", but I wouldn't do it with the landing gear down.

Just so much easier to change a tire, by lifting the axle an inch or so, than to lift frame high enough to raise the wheel.

Jerry

Another good point for lifting on the axle right under the spring. The small distance is no different than the axle steping over a small bump in the road.

kaydeejay wrote:

rhagfo wrote:
..............The issue for me jacking on the frame, is that it is so high, and you need to raise about 6" to 8" to get the tire off the ground.

Not to mention what that does to torque the frame if the front legs are down!
That's why I only jack up my fiver when it's hitched to the truck; that way it can rotate if needed.
And I jack under the U-bolts.

Both good points here from Russ, and Keith. I have heard people say "you don't need to be hooked to truck, to lift side of FW", but I wouldn't do it with the landing gear down.

Just so much easier to change a tire, by lifting the axle an inch or so, than to lift frame high enough to raise the wheel.

Jerry

rhagfo wrote:
..............The issue for me jacking on the frame, is that it is so high, and you need to raise about 6" to 8" to get the tire off the ground.

Not to mention what that does to torque the frame if the front legs are down!
That's why I only jack up my fiver when it's hitched to the truck; that way it can rotate if needed.
And I jack under the U-bolts.

Sandia Man wrote:
Preferably under spring hanger/u-bolt but looks like he was right next to it from photo.

X 10 or so, this works, directly under the spring is better, but with the wood and tight to the U bolt works.

The issue for me jacking on the frame, is that it is so high, and you need to raise about 6" to 8" to get the tire off the ground.

Under the axle you only need to raise about 2" total to get the tire 1" off the ground.

IF I need to lift off the ground then I will build cribbing under my bottle jack so it is stable.

laknox wrote:

2oldman wrote:

justme wrote:
...the more leverage towards the center where the precision bend is vulnerable.

There's a bend in the axle?

Most axles have a slight arch to them. This is how the proper camber is put on the tires.

That's why you can't really "flip" an axle (turn it 180 degrees) - the orientation of the axle must be maintained by moving the spring perches to retain the design camber.

Rusty

2oldman wrote:

justme wrote:
...the more leverage towards the center where the precision bend is vulnerable.

There's a bend in the axle?

Most axles have a slight arch to them. This is how the proper camber is put on the tires.

Lyle

justme wrote:
...the more leverage towards the center where the precision bend is vulnerable.

There's a bend in the axle?

NO don't jack from the frame. Tire guy is right. Best to jack from the axle right behind the wheel (u-bolts). Your not going to bend an axle lifting at the U-joints...

Pretty much the same reason you jacks are "stabilizing " jacks and not "leveling" jacks.