Levelling with wheels off ground

[No cats]

once said the coach would not roll even if all 6 wheels were off the ground

Hard to "roll" with no wheels on the ground, but I get what you mean.

I don't care how strong the jacks are, if only the back wheels are off the ground and the front on. In a considerable incline I would not chance it.

 

[Derby6]

And I assume you don't put anything under the wheels for support?

I have a hard time buying that such supports much. IMO, it will only put a little weight up on the springs. I don't see how those few pounds make much difference. IOW, whenever the levelling jacks are used, they are holding most of the weight of the rig, even when the wheels are on the ground. While there will be a difference, it is only a few pounds of difference. I doubt if it is enough to make a difference. Could make us feel better and that is about all, IMO.

Or is there more to it that I am not understanding?

-Don- Tehachapi, CA

I get what you're saying but if you could get it as close to possible level on wheels then jacks only lifting 1-2 inches to level--tires and suspension would still assist with some stability.
Then also using buckets, blocks, or whatever under the jacks make it more stable -- The thin jack ram will only have to extend minimally- vice many inches where you're up on extended rams that can/will have more sway.

 

[jymbee]

Ok, it's pretty obvious to me what we need to do here...

To start with, eight portable scales positioned under each front wheel, each back wheel, and under each leveling jack. Each capable of transmitting data wirelessly to a central weight distribution system (CWDS).

Next at least a half dozen bubble leveling devices strategically placed at locations inside the RV, each also capable of sending data to the CWDS.

Of course a few external laser calibration devices as well.

Then we'll need at least a few dozen RV owner volunteers and a number of volunteer campgrounds with sites that reflect a full range of level and unlevel sites.

Only then, with a team of engineers analyzing the collected data will we be able to definitively arrive at a meaningful conclusion that analyzes the collected data and takes all factors into account specific to each type of RV.

Then... we all can all continue to argue as to how this methodology was seriously flawed and how it should have been done.

Oh well...

 

[Onyrlef]

Ok, it's pretty obvious to me what we need to do here...

To start with, eight portable scales positioned under each front wheel, each back wheel, and under each leveling jack. Each capable of transmitting data wirelessly to a central weight distribution system (CWDS).

Next at least a half dozen bubble leveling devices strategically placed at locations inside the RV, each also capable of sending data to the CWDS.

Of course a few external laser calibration devices as well.

Then we'll need at least a few dozen RV owner volunteers and a number of volunteer campgrounds with sites that reflect a full range of level and unlevel sites.

Only then, with a team of engineers analyzing the collected data will we be able to definitively arrive at a meaningful conclusion that analyzes the collected data and takes all factors into account specific to each type of RV.

Then... we all can all continue to argue as to how this methodology was seriously flawed and how it should have been done.

Oh well...

Even if a link to one of those YT channels where Bob and Karen explain how to sweep off your RV steps is included ?

 

[Derby6]

Ok, it's pretty obvious to me what we need to do here...

To start with, eight portable scales positioned under each front wheel, each back wheel, and under each leveling jack. Each capable of transmitting data wirelessly to a central weight distribution system (CWDS).

Next at least a half dozen bubble leveling devices strategically placed at locations inside the RV, each also capable of sending data to the CWDS.

Of course a few external laser calibration devices as well.

Then we'll need at least a few dozen RV owner volunteers and a number of volunteer campgrounds with sites that reflect a full range of level and unlevel sites.

Only then, with a team of engineers analyzing the collected data will we be able to definitively arrive at a meaningful conclusion that analyzes the collected data and takes all factors into account specific to each type of RV.

Then... we all can all continue to argue as to how this methodology was seriously flawed and how it should have been done.

Oh well...

well you should’ve said something last year we probably could’ve easily gotten 1 million or billion dollar government grant.
But that ship sailed for now.

 

[Onyrlef]

well you should’ve said something last year we probably could’ve easily gotten 1 million or billion dollar government grant.
But that ship sailed for now.

When your only tool is a hammer.......

 

[Alaskansnowbirds]

The problem with just about anything we own these days, is that the engineers designed and built it and the lawyers wrote the operating manual with no engineering input.

 

[Gr8bawana]

Every RV park and campground we have stayed in had at least 1 RV with 1 or more front wheels off the ground.
There is ZERO danger of twisting the frame to the point of damage. The frame twists all the time with the bumps and twist of the road.

 

[DonTom]

Every RV park and campground we have stayed in had at least 1 RV with 1 or more front wheels off the ground.
There is ZERO danger of twisting the frame to the point of damage. The frame twists all the time with the bumps and twist of the road.

And this RV park I have both of my front wheels off the ground by a few inches. When I was boondocked in Kofa, one front wheel was off the ground and the other was barely touching the ground.

-Don- Tehachapi, CA

 

[Mark_K5LXP]

In a considerable incline I would not chance it.

There's a limit to "considerable", there's only so much jack travel. The travel distance of my jacks from moment of ground contact to full extension is 8 inches. Calculating the angle of that rise over the 18 or whatever feet of the wheelbase, it's just a few degrees. Clearly there's a lateral force limit to these things but practically speaking I'm not sure extreme angles, more than a few degrees, are a plausible scenario - you're not staying at a site that ostensibly can't be leveled in the first place.

Mark B.
Albuquerque, NM

 

[No cats]

The travel distance of my jacks from moment of ground contact to full extension is 8 inches.

8 inches plus any amount of blocks someone may be tempted to use.

I'm talking about having the rear wheels off the ground - no parking brake. Front wheels off the ground, I don't see a problem (as long as the jacks are rated for it.

 

[DonTom]

8 inches plus any amount of blocks someone may be tempted to use.

I'm talking about having the rear wheels off the ground - no parking brake. Front wheels off the ground, I don't see a problem (as long as the jacks are rated for it.

So far, every motorhome here in this RV park that I have seen so far has both of the front wheels off the ground. I wonder how many of them know--or care.

All the RV slots here face downhill, so that is why the front wheels are off the ground to get leveled. Other rigs I see (other than motorhomes) are leveled by other ways than jacks, such as thingies under the front tires.

-Don- Tehachapi, CA

 

[No cats]

I'll repeat myself. It's the rear wheels I would worry about. The ones with the brakes.

 

[DonTom]

I'll repeat myself. It's the rear wheels I would worry about. The ones with the brakes.

Yes, I realize that. And I wonder how often that happens.

I also wondered if the levelling system was designed to not lift the rear wheels completely off the ground. I have never seen rear wheels off the ground yet. It has only been front wheels so far--since I have been looking at other rigs parked.

-Don- Tehachapi, CA

-

 

[No cats]

Those of us with trailers (no brakes on the rear wheels) have to chock them. Many horror stories of trailers rolling off the campsites without them.

 

[Alaskansnowbirds]

Our MH's rear jacks had enough travel to lift the rear wheels off the ground. Did that once on one side to change a flat. Chocked the front wheels. With one rear wheel off the ground, I don't believe there is any braking because of the differential.

 

[Mark_K5LXP]

I'll repeat myself. It's the rear wheels I would worry about. The ones with the brakes.

Right, let's ponder that for a second. If the situation were the rears were on the ground and the brakes in effect, there isn't a concern. So, the rolling force of front wheels with no brakes at some nominal rearward angle is the question. Let's say for the sake of discussion the angles involved are within the range the jacks can level. Not a lot of force I would posit, but some number that a physics guy could deduce. Using my own RV as an example, my wheelbase is 16 feet, with an 8" rise of the jacks that's less than a 3 degree angle. So the rear jacks would have whatever rolling force 9 tons has at a 3 degree slope. That'd be worst case.

Now, per the above few posts the idea of chocks is offered. I don't see how chocks on the front would be fundamentally any different than brakes on the back. Maybe place the chocks, kick off the brake to take up any slack, jack up the rear and check the box. Carrying that thought another step, using the front jacks to anchor the front would accomplish the same thing, though some lift would probably be necessary for the jacks to establish a foothold. But same difference - if the rig is level, the jacks are in line with gravity and there's no lateral force.

I read this and other RV forums. Forums arguably contain reports and questions from users generally when there's a problem, not when things are OK. Over the likely tens (hundreds?) of thousands of forum posts I've read over the years, I've never once read a report where a jack failed due to terrain angle. Reports of failed hoses, valves, broken springs, leaks, feet that fell off, windshields that pop out but never one where the RV was jacked up and the thing keeled over. I get that lack of evidence is not proof but my observation this is not a pervasive problem. From an engineering standpoint if the jacks or chassis were not mechanically able to withstand these forces, then it would be basic system implementation to ensure the jacks could not extend to the point of failure. But, apparently there's data to support there won't be catastrophic failure with systems that are in common use. Hydraulic jacks bolted to RV frames in their current configurations have been around long enough to discover edge cases and I don't think a few degrees lateral force is one of them. But leave it to the masses to test design limits, so mitigate the liability with a CYA admonishment of don't do this in the instructions. But with a modicum of "common sense" in use there probably won't ever be an issue. I'm OK with being the field tester.

Mark B.
Albuquerque, NM

 

[Onyrlef]

I'm thinking the caution not suspend the rear wheels in the air on a rear wheel drive vehicle, especially on a slope and in consideration of the gravity thing ( otherwise the jacks wouldn't need to raise the rear wheels off the ground) is due more to walking around sense than anything else.

 

[No cats]

Mark, I agree with your post #97.

As an interesting perspective though, consider this. When driving through mountain areas, there are warnings when you will be entering a 6% grade. A 6% grade equates to 3.4 degree angle.

"In the United States, the maximum grade for federally funded highways is specified in a design table based on terrain and design speeds, with up to 6% generally allowed in mountainous areas and hilly urban areas with exceptions for up to 7% grades on mountainous roads with speed limits below 60 mph (95 km/h)."

 

[Gary RV_Wizard]

I've parked two different coaches on a site that was uphill, i.e. the nose noticeably higher than the rear. The rear wheels come off the ground about 3-4 inches. This was at a friend's summer home that we visited for a week or so every summer, so not a one-time thing. One 22,000 lb coach had Power Gear levelers and the other (34,600 lbs) was Equalizer. The wheelbases were 19 ft and 23 ft, respectively. Mindful of the cautions about rolling, I always kept a foot on the brake pedal as the rear came up but never a sign of movement. Chocked the front wheels just to be sure, but again no indication the coach had shifted after a week or so. Both coaches had very capable jacks. I even wrote to Equalizer about the risk of bending and their response was basically "not gonna happen". I could tell that reply came from tech staff - no lawyer weasel-words anywhere!