How important are leveling jacks?

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ArdraF said:
Bob, thanks for the HWH info.

At least with two Bigfoot-style jacks on the front, there might be a better chance of reducing the damage.
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You are welcome, Ardra. The argument that 3 points make a plane, and a tripod is used by surveyors and such because it is easy to level does not stand up (no pun intended  :)) with me. A tripod is easier to set up, but is not as stable once set up as a quad-pod. If I had a small model of an RV on 3 jacks setting on the floor -- I could easily "twist" the front end on that single pivotal point, but not the rear. All three legs of a tripod come together under the load and equally share the total load, whereas the 3rd RV jack is 4 or more times farther from the other two than those 2 are together. So the rear two give no lateral support whatsoever to the front end load and do not share that load.

Did you know that Bigfoot named their company Quadra Manufacturing to emphasize the importance of 4 jacks vs. 3?  ??? ;)
 
Bob,

The whole idea of the 3 jack system is to get the front off the collapsed bags by raising the front slightly. Now the pivot point is the front jack, not the frame. I agree 4 points are more stable but too many frames were twisted and windshields popped. That's why all new systems now operate two jacks in tandem, both front or both rear or both on either side. This prevents the twisting. I think much more damage was done by the independent 4 jack systems than any 3 point system. :)
 
Jim Dick said:
Bob,

The whole idea of the 3 jack system is to get the front off the collapsed bags by raising the front slightly. Now the pivot point is the front jack, not the frame. I agree 4 points are more stable but too many frames were twisted and windshields popped. That's why all new systems now operate two jacks in tandem, both front or both rear or both on either side. This prevents the twisting. I think much more damage was done by the independent 4 jack systems than any 3 point system. :)
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My references and general observations are based on 4 point bi-axis leveling as used by HWH and Bigfoot. How long ago has it been that any 4 point leveling systems were not bi-axis?. That would be excellent info for the originator of this thread -- in terms of what "not" to buy.

Are you saying that 3 point systems are "only" to slightly raise a rig off an air bag? I thought there were vendors that sold 3 point systems for any type of Class A rig. As Ardra mentions, I also note rigs in parks that have many sites that slope pretty drastically. For example, Boomtown in Verdi outside of Reno and CalExpo RV park in Sacramento. I see many big rigs with the single front jack fully extended, plus sitting on blocks as well.

Oh well -- as Ron suggests, it's a feature of a MH that is a personal preference. And I respect that. I just would not want to be parked in front of a rig with a single front jack fully extended, or the carrier of the insurance on the frame of that rig. :eek:  :)
 
Bob Buchanan said:
Oh well -- as Ron suggests, it's a feature of a MH that is a personal preference. And I respect that. I just would not want to be parked in front of a rig with a single front jack fully extended, or the carrier of the insurance on the frame of that rig. :eek:  :)
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I can't see where it would make any difference between a single jack being fully extended, a condition we have never experienced, or having two front jacks fully extended.  In any case raising the tires off the ground is not recommended.  Raising the rear tires could lead to serious consequences on most coacjhes since the parking brakes are only on the rear wheels.
 
Raising the rear tires could lead to serious consequences on most coacjhes since the parking brakes are only on the rear wheels.
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We've seen that too - too many times!

ArdraF
 
Bob,

I don't remember when they went to the new 4 jack systems. It would be good to know that information for future buyers. Maybe someone does have it.

No, I'm not saying the 3 point system is to "only" raise it slightly in front. What I am saying is if you don't raise it then you are sitting on the frame and any adjustment with the rear jacks could cause frame twisting or windshield popping. When you are not up on the front jack then you have a rigid front end that cannot pivot properly in the center.

Fully extending any jack system, 3 or 4 point, to the max and raising the wheels off the ground is certainly not using the system properly. If the site is that off level then I would ask for a different site! The other solution would be to drive up on blocks until semi level and use the jack(s) to finish. The jack(s) might have to be blocked as well but wheels should never be off the ground!! Raising the rear wheels off the ground is even worse since the parking brake works on them.
 
Thanks to all for this info....it has been so helpful !

I am one of those who find myself at a campground with a season site where to level my coach with the three point jack system actually brings the front tires about six inches off the ground. I spoke with the campground owner and said something about bringing some gravel in to level the site and they did, but not near enough. When they told me that was all they could bring, I decided to bring some in myself and still need more because the tires are still off the ground. I'm afraid to bring in more for fear of getting the site so high in the front that the rear of the coach is dragging the ground when I back into the site.

I was always afraid that to have the front end lifted completely off the ground with a single jack was not good so I do not even use the jacks right now. When weather here in the Chicago area warms up I am going to work on a solution. Again thanks for the insight and now I feel better about my worries and know I need to fix the problem. Plus I now see some cracks in the windshield that were not there when I bought the coach and was concerned the campground site was the culprit :mad:

Phil
 
Whether four or three point jack system it is not good to have the tires off the ground.  As far as the capability to carry the load the single (usually 12000 or 16000 LBcapacity)  will do just as well as two (usually 6000 or 8000 lb capacity) jacks.   Why not use some of the plastic leveler blocks to sett under the tires?

Leveler blocks can be purchased on line from PPL HERE . Check it out photos and description are included.  Also they are currently on sale.
 
I was going to talk to the management about using their bobcat and grade the site level. Now that I have brought in the gravel all I really need to do is dig the rear down and drag it forward then use some of the new gravel to clean up the lot. If they don't want me to do that then I was thinking about building some ramps. The leveling blocks look appealing also, then I could carry them with me wherever. Thanks guys.

Phil
 
Ron said:
As far as the capability to carry the load the single (usually 12000 or 16000 LBcapacity)  will do just as well as two (usually 6000 or 8000 lb capacity) jacks.
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Ron, it isn't the bearing load I would be concerned about. That isn't the issue with those that disagree with the 3 point system -- such as HWH and Bigfoot. It's the live lateral loads that would tend to "pivot" the rig on that single jack such as wind, plus the other live loads of occupants moving around inside, or congregating on one side or the other, or a single 1500 to 2000# slide extended "after" leveling takes place. A dinette in a slide could could all of a sudden add 500-600# at meal time that is leveraged by the distance to the center of the rig. Not many RVers weigh and take note of side to side loading vs. front and rear axle. If not even, that would also tend to twist the rig on a single front jack.
 
Ron said:
Whether four or three point jack system it is not good to have the tires off the ground.  As far as the capability to carry the load the single (usually 12000 or 16000 LBcapacity)  will do just as well as two (usually 6000 or 8000 lb capacity) jacks.   Why not use some of the plastic leveler blocks to sett under the tires?

Leveler blocks can be purchased on line from PPL HERE . Check it out photos and description are included.  Also they are currently on sale.
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And if you do not know how the blocks work, just ask the nearest trailer trash.  ;D
 
Ron said:
Or ask some kid that has played with leggos. ;D
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So they should look for trailer trash that played with Leggos as a kid?

What motor homers need is a good hitch jack.  ;D

 
Attendees at the 2006 RV Forum Moab rally solved the issue of lateral balance on 3 jacks. As the photos show, it's all a matter of distributing the load evenly  ;)

Folks, don't try this on 4 jacks.
 

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Tom said:
Attendees at the 2006 RV Forum Moab rally solved the issue of lateral balance on 3 jacks. As the photos show, it's all a matter of distributing the load evenly  ;)
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LOL.  Yes we did have a lot of ballast there. ;D
 
author=Bob Buchanan link=topic=15311.msg143194#msg143194 date=1202017020]
HWH seems to disagree, Ron. THIS quote from their website:
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Hmm, it would seem that HWH are the "experts" when it comes to leveling, but I sure don't agree with that quote.  For 8 years I had a motorhome with a 4-point system (front worked in tandum), then last year I bought a Monaco with a 3-point system.  At first I was concerned, but I've grown to appreciate it much more. 

First of all, the purpose of Monaco going to the 3-point jacks was NOT to save money, it was to save windshields.  You put the front jack down first and you automatically have a pivot point for the front of the coach to revolve on during both leveling and jack retraction.  That saves an awful lot of frame twisting that might otherwise pop a one-piece windshield. 

Also I've found it much easier to level with three jacks.  It's so easy, I don't even use the automatic leveler anymore.  Just put the front jack down first to gain that "pivot point", take the rear jacks to the ground, level front to back, and tweak the rears once to lift the low side.  You're done.  As for stability, I found a very slight amount of additional movement while walking within the coach, but hardly enough to notice and certainly not enough to be bothersome.

 
Hi Robmorg,

Though I agree completely on the three jack system it still saves them money. Under warrantee they would most likely have to cover broken windshields. With the three point system that problem is almost eliminated!! ;D
 
Jim Dick said:
Hi Robmorg,

Though I agree completely on the three jack system it still saves them money. Under warrantee they would most likely have to cover broken windshields. With the three point system that problem is almost eliminated!! ;D
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The problem is only eliminated IF the operator follow instructions. ;D ;D
 
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