Frame flex

[Jim55]

For several years there has been a real and growing problem with defective frames on the montana line. It’s been referred to as “frame flex”. I’m not trying to stir up any trouble here, as I have a sincere question.

I’ve been a full time RVer for seven years and am considering buying a High Country 330 or Avalanche 313 or 320. My question is. . . Are the above mentioned models known to have the bad frames? Or is this problem limited to certain models? My purchase would be new or nearly new.

Thanks for any info you can offer. Jim

[PNW Fireguy]

The term frame flex is actually regarding a poorly designed/installed connection between the stud wall and the frame. The Lippert frame is not actually the problem but rather the mechanical connection of the sidewalls at the point of frame drop near the front.

[richfaa]

Lippert makes the frames for Keystone I cant imagine them making "bad frames" it would not be very good for business. Frame flex is a general term used for a couple of different issues. There is frame flex caused by a actual breaking of the frame usually in the overhang portion of the 5th wheel. There is what we call frame flex that is caused by the separation of the gel coat wall from the aluminum frame work it is attached to . The frame itself is not broken but the visual symptoms look the same. We had the problem on our06 3400 Montana.

[Jim55]

Thanks for the quick responses. Do you have any idea if there are any statistics that would indicate which models this problem is prone to occur in?

Jim

[jsb5717]

I've seen some posts here and there talking about frame flex as evidenced in seeing a crack in the fiberglass below the front slide. I haven't seen anything to indicate a systemic issue with any one brand or model. It seems to me to be a "one-off" issue like many other manufacturing defects. Since it's all built and assembled by humans it's possible for anyone to end up with a problem here and there. It's also difficult to determine how any particular rig was treated or what it was exposed to in travel that may have encouraged frame flex. My own layman observation is that it's typically the longer trailers (38-42') that might be more susceptible to flex. I have no scientific data, just personal observation.

I wouldn't hesitate to buy any of the models you suggested. The HC's use a 10" I-beam frame. I'm not sure what size the Avalanches have.

[DQDick]

It has seemed to me that problems with the actual frame have diminished in the last few years and our newer rig has a much beefier frame than our 2010. The wall issues seem to have increased which may or may not be a result of the underling frame being stronger. You can see similar issues being discussed on other manufacturers forums so I would agree that it's more the luck of the draw than a specific model or make.

[bshgto]

Originally Posted by DQDick

It has seemed to me that problems with the actual frame have diminished in the last few years and our newer rig has a much beefier frame than our 2010. The wall issues seem to have increased which may or may not be a result of the underling frame being stronger. You can see similar issues being discussed on other manufacturers forums so I would agree that it's more the luck of the draw than a specific model or make.

that`s funny mine has it, I fixed it cause camping world just kept looking at it with a question mark look on their face and finally said you can`t fix a vacuum bonded wall that strengthens the frame.
Many many new campers on facebook that have had or have it along with varing brands with the lippert frames. Many newer campers on RV Horror stories complain about this with some get fixed, some get fixed then breaks again, some never get fixed. Not until 2020 did they change the wall design on the nose that they think will fix this issue, but the jury is still out on this one as it has not proven themselves to do a correct redesign that is guarantied to work. I wouldn`t let this issue stop your purchase as said it is the luck of the draw or the roads you travel which I think is the real problem. Mine didn't start till I hit a pot hole that rattled my teeth. I would look for the redesign nose on the unit your interested in or just role the dice. Good luck, Lifes short, keep moving forward.

[Jim55]

Originally Posted by bshgto

that`s funny mine has it, I fixed it cause camping world just kept looking at it with a question mark look on their face and finally said you can`t fix a vacuum bonded wall that strengthens the frame.
Many many new campers on facebook that have had or have it along with varing brands with the lippert frames. Many newer campers on RV Horror stories complain about this with some get fixed, some get fixed then breaks again, some never get fixed. Not until 2020 did they change the wall design on the nose that they think will fix this issue, but the jury is still out on this one as it has not proven themselves to do a correct redesign that is guarantied to work. I wouldn`t let this issue stop your purchase as said it is the luck of the draw or the roads you travel which I think is the real problem. Mine didn't start till I hit a pot hole that rattled my teeth. I would look for the redesign nose on the unit your interested in or just role the dice. Good luck, Lifes short, keep moving forward.

Any idea what this change in wall design was in 2020?

[jetskier]

Originally Posted by Jim55

Any idea what this change in wall design was in 2020?

If I had to guess, the wall panel completely wraps around the whole front slide assembly rather than be discontinuous at the bottom. This wouldn't necessarily increase strength, but make the two systems (wall panel and frame) more compatible structurally for deflection (flex).

[Mikendebbie]

This is my question...does frame flex/broken wall studs tend to occur more often in units with a slide-out located closer to the front and over the step in the frame for the raised front area?

If you look at my pics below - I drew a dotted red line across the area of the nose where I think maximum moment will occur under load (i.e. when hitched to the truck). Some units have a solid section of bonded wall thru this line. Some units have a large opening thru this dotted line. Seems like if there is more "meat" (solid wall area) to resist the moment - then the structural engineers should be adding "meat" to counter act the lack of "meat" when a slide opening happens along the red dotted line. I do not know the answer - but I wonder. I would love to get a peek at Keystone's statistics on this for failure rate. But if this was a factor - seems like they would have addressed this and eliminated the problem by now.

[Vet4jdc]

Originally Posted by Jim55

For several years there has been a real and growing problem with defective frames on the montana line. It’s been referred to as “frame flex”. I’m not trying to stir up any trouble here, as I have a sincere question.

I’ve been a full time RVer for seven years and am considering buying a High Country 330 or Avalanche 313 or 320. My question is. . . Are the above mentioned models known to have the bad frames? Or is this problem limited to certain models? My purchase would be new or nearly new.

Thanks for any info you can offer. Jim

Search Frame Flex and see if you can find a survey that will help answer your question. Someone did a complete survey on the subject that has some numbers.

[jeffba]

Your middle 2 pictures are where most of eh failures I have seen occur. New in 2020, a smaller bedroom slide to make the failure area taller and therefore, hopefully, stronger.

[bshgto]

Originally Posted by Jim55

Any idea what this change in wall design was in 2020?

yep saw a pic on here that shows the difference . Mine has 4 inches of support under the bed slide to hold everything together like the second pic on the previous post, not much when you dive into a pot hole. This puts all the stress on the few remaining studs and horizontal members top and bottom in front of the slide, they cant take the beatings and break loose like mine did. The new design is about 1 1/2 ft of support under the bed side, more meat more support but the bed side is smaller in other words less head room inside above your head. It`s on here some where you can look for it.

[jetskier]

To further elaborate on my previous post...the reason the studs are breaking there is the re-entrant vertical force on the aluminum wall stud caused by the discontinuity of the wall panel at this location. Even though this is not a place of maximum moment in the frame, there is upward curvature in the steel frame when the trailer is hitched up. The measured relative deflection at the front of the slide opening from this curvature creates a force that is too much for the aluminum stud framing and it's connection to resist. After many fatigue cycles, the aluminum fractures and busts out the siding panel. Having a continuous horizontal framing member in the wall panel below the slide accomplishes a few things. 1) It provides a boundary member on the bottom of the slide opening to resist moments, shears and deflection, 2) it removes the re-entrant forces at the lower front corner and 3) it provides more length to make the connection of the wall to the frame at the slide. This is likely the reason for the 2020 design change under the slide.

And yes, if you haven't figured it out, I am a structural engineer.

[bshgto]

Yes that all sounds good but none of it helps the pre design change camper of which there are thousands waiting to break with only a band aid to fix them and turn you loose on the bad roads again to break yet again. Thankfully mine has not as I did far more in reinforcement than the Keystone advised the dealers to do, cost you know. But really all I did was move the stress to a new location on the wall, I`ll see if it holds, so far so good. I suppose you can guess I am not a structural engineer.............

[Baldicon]

Originally Posted by bshgto

Yes that all sounds good but none of it helps the pre design change camper of which there are thousands waiting to break with only a band aid to fix them and turn you loose on the bad roads again to break yet again. Thankfully mine has not as I did far more in reinforcement than the Keystone advised the dealers to do, cost you know. But really all I did was move the stress to a new location on the wall, I`ll see if it holds, so far so good. I suppose you can guess I am not a structural engineer.............

My 3121 goes to the dealer for the frame flex problem. I've seen pictures of the repairs and looked over the repair TSB. Can I ask what you did differently than the TSB calls for? Pictures?

[Mikendebbie]

Originally Posted by jetskier

Having a continuous horizontal framing member in the wall panel below the slide accomplishes a few things. 1) It provides a boundary member on the bottom of the slide opening to resist moments, shears and deflection, 2) it removes the re-entrant forces at the lower front corner and 3) it provides more length to make the connection of the wall to the frame at the slide. This is likely the reason for the 2020 design change under the slide.

That makes sense. Do you know what they are using in the new framing configuration for the continuous horizontal framing member? Maybe a tube? I wonder if they talk about it in the factory tours?

I suppose if the chassis frame front cantilever was beefed up to completely carry the load (by that I mean the forces) - would it relieve the stress on the studs and track? It’s probably more cost effective to insert more beef in the track section as you previously mentioned.

[richfaa]

Our 2013 Montana Big Sky has not had a problem of any kind our 2006 Montana 3400 did not have a broken frame but did have the sidewall separation. The 3402 has about 60 K miles on it. We did add the Mor Rye IS system and the trailers saver BD 3 hitch on the 3402.

[bshgto]

Originally Posted by Baldicon

My 3121 goes to the dealer for the frame flex problem. I've seen pictures of the repairs and looked over the repair TSB. Can I ask what you did differently than the TSB calls for? Pictures?

As I was standing there with a water fire exstquiser while the welder was working I thought I should take pictures of this but didn`t as I was fighting the weather working out side. I did not remove the slide that would be a deal breaker, I removed the outside trim, the motors and the chest of drawers in side and just pushed the slide in with help of course, did not remove the cap either just raised it up enough to gain access to the front stud, all 3 were broken,just added more and heavier on the factory idea with lager 2x8`s instead of 2x6 with longer and larger screws from the steel ledge that the whole mess sits on up into the 2x8` along with aluminum gussets at all stud intersections top and bottom.also removed the skin under the nose to add steel gussets at all the intersections. The glue and gun you can buy on line for wall replacement. Not hard just time consuming and a couple of scaffolding from the rental store. One thing I did do is use a seal with a water wipe on it that you can get from Orvin in Indiana that way you don't caulk the trim piece under and on the side of the nose. I would insit on that instead of replacing the orinanl trim piece that moves when it dose flex and breaks the silicon loose. It`s called UDF corner extrusion seal only 21.00 dollars for enough to do the job.He uses this on all his frame flex repairs. yeh I know it`s not suppose to move but it will you have broken the integrity of he wall with cutting it loose from the rest of the wall. Good luck.

[Golfmedik]

Look at the space under the bedroom slide from the overhang. This is the new design which has more wall to hopefully stop the bulging and then breaking of the welds in that area.