Frame flex?

[mtheo]

I just would like to know what percentage of Montana have this problem. I haven't had the problem, but my unit is lighter. I love ours and prefer a 5th over MH, but I have never heard of them with this problem. Don't get me wrong, thy have here own problems.
I'm not sure what I'll be buying in the coming years, 5er or MH

 

[richfaa]

I don't think there are published numbers on frame flex problems. remember these forums report problems. We do not know how many Lippert frames have been made or how many had frame flex. My guess is a very low %. Unless you had one then it is 100%.

 

[bncinwv]

Neither our 2007 3400 nor our 2011 3750 exhibited any problems associated with frame flex. I believe it is a function of the welding process at Lippert (the frame manufacturer) and what the welder was doing the previous night! I have been curious if the new rigs with the 12" frames had any structural changes in the nose area as well. Another investigative task for the factory tour attendees at the rally? Just a thought.
Bingo

 

[jhudson]

When did Keystone start manufacturing Montanas with the 12" I beam frame? I still plan to monitor for issues but I do feel better that is may be a low population that experience frame flex. Hopefully I will not be in that population.

 

[bncinwv]

I do not know if the 2013 models had the 12" frame, but the 2014 Montana models with the Paramount package do have it according to the Montana web-site.
Bingo

 

[Irlpguy]

It is my opinion having had to deal with frame flex on my 2012 that every lippert frame that employs the drop frame and short upper deck support system has flex, it cannot help but have it.

If the outer wall on your bedroom slide side does not separate from the wall frame in the vicinity of the expansion joint then you may never notice the fact the frame is flexing on that side. If your closet wall has sufficient clearance to accommodate the movement, you may never see any indication of flex on the other side either.

In some extreme instances there have been broken welds under the upper deck, there were no broken welds on my unit, but the wall separated and the closet wall buckled.

Did re-gluing the wall and cutting a section out of my closet wall solve the issue of flex, "NO" it did not, but it is not visible anymore. Other than the 3/8" difference in where the decal used to line up. However if I want to confirm it is still happening, I just take out the bottom drawer in my closet and using the remote lower the weight onto my hitch. Quite an eye opener I assure you.

If you think your frame is not flexing, then put a camera on the pin box and record what is happening to the space between the pin and the front cap as you travel down the road. If you think your frame has no flex, then measure from the two front corners of the frame to the pin with the weight on the landing gear and then with the weight on the pin, as per the lippert document just for that purpose. They do have an allowable movement.

Who on earth is going to publish frame flex problems, it sure will not be Keystone or Lippert. The problem is not minimal it is 100%, the "manifestation" of the flex is a far lesser percentage.

If you are interested and are doing the factory tour, pay particular attention to the area of the frame where the upper deck is forward of the main frame, pay attention to the distance the main upper deck side supports extend back of the front of the frame, and what material is used here. The whole upper deck is basically supported by 2" x 5" tubing that runs along the side of the upper deck, bent to form the front, then to the back of the propane compartment, there are cross supports of the same size to support the pin and some 1" x 1" tubing under the upper deck floor but that is it folks.

Now extend that pin box out beyond the front of the upper deck frame and put upwards of 2500 lbs on it and take a wild guess as to where the frame is going to flex. Now hit a dip in the road and imagine what additional forces are at play here. You don't have to be a rocket scientist or engineer to see there "has" to be some flex happening on all of these frames.

Just MHO...

 

[jhudson]

I agree that the frame needs to flex. Just like my Titanium's the frame flexed too. The problem was in the Titanium case is the knee wall, part that starts the step up over the truck bed was weak and failed causing the walls to break bolts connecting them to the frame. This allowed the pin to move in and out of the coach. Once the knee wall was reinforced and bolts replaced everything was fine and yes the frame still flexed.

What I am concerned about is the same issue. Maybe not the knee wall but other items that connect to the frame and cannot handle the flexing and in turn fail. My Titanium's frame did not fail, however did flex. I don't believe frames can be completely solid without any flex or you most likely have more problems.

However is the frame flex so bad in Montanas that welds and metal start to fail? If this is the case, the frame was not designed very well and may be not be fit for its intended use. I really don't believe this is the case but it does make you wonder.

 

[richfaa]

The frames do break the welds at the overhang. Mine broke. How much of that is due to overloading and excessive pin weight is unknown as no one will admit it. The first time we were weighed we were nearly 1,000 lbs over weight much to our surprise but we had not experienced a broken frame. We did a serious weight reduction and had the Mor Ryde Is installed. The frame still broke at a later date. I don't think the frame on the 06 400 was sturdy enough for the IS system and additional weight.

 

[Chip-MOC]

My 07 frame broke. After repair I had some excessive flex going on. Probably induced by the failure.

 

[Irlpguy]

There have been documented instances here on the MOC of broken welds under the upper deck, it certainly does happen, but even without having a weld break the frame will flex and causes the kinds of problems a lot of owners have encountered.

The Titanium likely used the lippert frame as do many other manufacturers of RV's, so the problem is not unique to Keystone. How and where it shows up depends on how the rest of the superstructure is attached to the main frame.

Being overloaded and hitting a major dip in the road can certainly put enough additional strain on the area to cause welds to break. Having seen a lot of the welds on these frames I am not surprised at some of them failing.

We demand lighter, larger RV's and they are giving them to us by sacrificing the strength and integrity of the overall unit.

 

[Chip-MOC]

A major dip in the road that I did not see ahead of time is what broke welds on my first Montana.

 

[jhudson]

Same thing with my Titanium, Major rough road around Richman VA broke the knee wall allowing extra movement of the pin.

 

[Chip-MOC]

Yes and once the steel is sprung you can't get it back to its original position and keep it there without reinforcement of some kind otherwise it will just spring back - hence the induced flex.

Why do some flex more than others right from the factory?
Difference in the steel or bad assembly?

 

[bncinwv]

quote:Originally posted by Chip


Difference in the steel or bad assembly?

That will take some investigating, there have been many reports in the last few years of sub-standard "Chinese" steel being dumped on the market. If I remember correctly, there was a car manufacturer that had problems with brake rotors because of the source of the steel. Wonder if we have "Chinese" steel that in some instances is rolling around on "Chinese" tires???
Bingo

 

[Chip-MOC]

I HOPE NOT!!

 

[The Oldguard]

Indiana has one of the largest steel manufactures in the U.S.