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Old 10-29-2021, 11:30 AM   #61
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Originally Posted by Chateau_Nomad View Post
After returning from our most recent trip I noticed a kitchen cabinet door not closing... as if the (non adjustable) hinges had slightly shifted. Something other than humidity had caused the doors to rub at the top edge.

So what changed? I had Big Foot levelers installed before this travel season started. I have considered that the torque stress possibly contributed?

That's only a W.A.G., but if frame torque/twisting is a contributing factor to that, how might it contribute to distortion of the full-wall slide room and components?

Something to consider...
Torque and twisting from leveling contributed to exposing the front cap attachment wekaness and failure on my 2020 Magnitude SV34. After 5000 miles I could see the gaps opening and closing where the front cap attached to the houe box and also the cab.

This goes to my earlier post about this being a contributing factor to slides postentially failing prematurely if the Scwintek system has a tolerace of 1/8" at all of its critical measurement points. Even if the tracks are perfectly parallel on the slide wall any twisting of the house would cause issues with H-Column alignment.

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Old 10-29-2021, 12:35 PM   #62
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Originally Posted by RACarvalho View Post
I agree that the FWS leaves, in theory, the MH box weakened by having a big hole there but you can design a cage with a big hole that is more rigid than another w/o it... It depends on the design....
Also, the entire thing is bolted to a chassis that will twist in first place ...
If the big hole of the FWS was weakening the structure to a point of concern, we would have problems in other areas like the cabinets attached to the wall/ceiling on the other side of the coach, etc.
Obviously the box structure is already designed to get to the rigidity that they want but the corners by the back end are where you expect to see more movement and +-1/8in of tolerance will not/is not making it...

As for the "cheap" aspect of it, I see it both ways:
First, obviously no one likes to pay for something that doesn't work so whatever doesn't work needs to be fixed.
Se!!!
In my opinion, based on a lot of facts and observations, RV house framing is weak and not designed to handle the inherent twisting that occurs. There are similarities between a house, sticks and bricks, and an RV, pick your type (TT, 5th wheel, motorhome, park model, etc.) First is the foundation. For the RV it's the frame, house the slab or built up footer and framing. Then the house structure. RV can be 1.5" wood or up to 3" aluminum or steel. House is minimum of 2x4 and goes up from there depending on region and building codes. Windows and door headers. Housing generally for dimensional lumber the header height is equal to the width so a 12' wide garage will have 2x12 header doubled. Larger will usually have engineered headers and such. Your RV??? Look how much space there is between the top of a slide and the roof line. Do you think Judges 23' slide has an engineered header, do you think my 6' bedroom slide had a 6" header?

Back to frames on RVs. The weakest are TT and they flex the most. Some better 5th wheels have 12" beams but those are better and more expensive, most 10 or less. In motorhomes light weight C on a F350/450 or equivalent, up to F550 and equivalent then to Freightliner and Spartan varieties on larger A and really larger super C. Even those heaviest A on the heaviest FL frames twist and tweak, FACT. That flexing of the frame and the already under engineered house framing result in a rather weak structure that now they cut the hole for the slide and pretend that it's strong and stable.

The strongest structure of any RV is the smallest and without slides. That of course isn't what most of us want so we accept inherent structural weakness and hope it doesn't fail in our lifetime of ownership. Take a 30'+ TT and support it with the tongue jack and rear stabilizers taking weight off the wheels. Now try to open doors or run a slide of any size out. It'll be a "mess". Interior cabinets suffer from the forced out of square which we see as cabinet doors binding, loosening of hinges and doors, etc.

Many like to liken the RV as an earthquake on wheels which is a good analogy. How many S&B homes do you see that are 30, 40+ years old and still doing fine structurally. How many RVs that are a mere few years old collapsing in their own dust, many especially if used regularly. The typical RV buyer is drawn to the pretty design, interior colors, wide open spaces, latest technological gee whiz thing, and doesn't give the first thought to what kind of bones it has. People buy what they want, bottom feeder manufacturers give them that with almost non existent warranties (1 year) with the cheapest components in them. Caveat Emptor which most don't even know what it means much less exercise.

My Friday morning drinking coffee thoughts.
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Old 10-29-2021, 12:38 PM   #63
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Originally Posted by Judge View Post
Torque and twisting from leveling contributed to exposing the front cap attachment wekaness and failure on my 2020 Magnitude SV34. After 5000 miles I could see the gaps opening and closing where the front cap attached to the houe box and also the cab.

This goes to my earlier post about this being a contributing factor to slides postentially failing prematurely if the Scwintek system has a tolerace of 1/8" at all of its critical measurement points. Even if the tracks are perfectly parallel on the slide wall any twisting of the house would cause issues with H-Column alignment.
The slides seat on rollers in the floor which also twists with the system so you have a twist in the floor that leads to a twist (to a smaller degree) of the slide box while the house "cage" is twisting on a different way...
If you think about it, it is really a surprise that only the rear motor/track seems to present the majority of the problems.
As I stated , my driver side slide, which is just behind the driver and is 11ft long never had a problem so the torque in the structure at mid ship is not enough to make the system fail....

Another factor I learned is that the rollers under the slide can be adjusted in hight by a screw in front of them (inside of the coach) and depending on how many rollers are out you can have different problems like too much pressure on the Schwintek rollers because the floor rollers are too low or the slide tendency to move sideways when a roller at the end is too high...
A way to see if the floor rollers are applying equal pressure is to see the lub marks in the plates under the slide. If the marks are too different, the rollers are not applying the same pressure...
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Old 10-29-2021, 12:53 PM   #64
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My saving grace may be that I NEVER extend the slide room unless the coach is level. I admit I have "bumped" the levelers on the slide side a few times to correct for a very slight difference in level with the slide in vs out. I just winterized the other day and inspected the slide tracks - which show no signs of wear at all - so far... fingers crossed.

My plan is to use a self-built electronic leveling device. Then calibrate (with slide IN) to show slightly high on the slide side... then, when the slide is extended, it drops to perfectly level. Anyway, that's my plan to eliminating using the "bump" method, and potential jarring/racking of a loosely supported (when extended) slide.
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Old 10-29-2021, 01:09 PM   #65
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In my opinion, based on a lot of facts and observations, RV house framing is weak and not designed to handle the inherent twisting that occurs...
Previous to this I had a Rockwood 29' camper (model 2909WS).
That thing was 35ft hitch to bumper and had 3 slides on the same side!
I guarantee the frame rails in that camper where no where near the rigidity this MH frame has...
We put ~ 25K miles on that camper in 3 years facing all kinds of weather and roads and we had no problems with all three slides.
The two bigger ones where rack in pinion through frame system and the bedroom wardrobe slide was schwintek.
I'm telling all this history to say that while I agree that manufacturers tend to put the cheapest thing they can get away with, I don't agree that that the cage structure is not designed to handle the twisting and the reason is that too much twist in the cage frame would lead to solder failure in the aluminum frame within the walls, cracks in the external gel coat, etc.
The problem we are discussing here, I believe, is not structural but the choice of the slide system.
Coachmen (which produces some very price competitive motorhomes) uses a different system for their big FWS... why?

I believe what Thor faces here is the old political game inside the company where designers are stuck with a certain system (Schwintek/ 3Track) just because the company bought that system so now you need to use the "in house" solution instead of the best solution (that may even be cheaper? Coachmen?)...

BTW, every time my FWS slide got stuck I overrode it and I was able to close/open the slide.
Before they changed the parts I reached the point where I had to do it every single time (I had a pencil by the slide control box ready for that ), we did a 2 week/2400 miles trip with the rig in this condition and the slide went out and in perfectly in override mode every time...
To me that is another evidence we are not talking about structure problem but a slide system choice problem....
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Old 10-29-2021, 01:25 PM   #66
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My plan is to use a self-built electronic leveling device. Then calibrate (with slide IN) to show slightly high on the slide side... then, when the slide is extended, it drops to perfectly level. Anyway, that's my plan to eliminating using the "bump" method, and potential jarring/racking of a loosely supported (when extended) slide.
With a shorter rig your should have less/no problem with the twisting we are talking about.
Do you use auto leveling?
If yes, I would manually level, then deploy the slides, then correct the level again manually, then reset the zero point in the auto level.
That should put the auto level at the right zero point.
In my previous rig , a pull behind, I had set the side with the slides 1in higher than the other side so when the slides where out the camper would be level side to side...
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Old 10-29-2021, 01:39 PM   #67
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e rig in this condition and the slide went out and in perfectly in override mode every time...
To me that is another evidence we are not talking about structure problem but a slide system choice problem.
...[/QUOTE]

If the structure is so great, why do you think the slide was regularly binding? Slide boxes themselves can get out of square as well as the slide opening in the side of the RV. That weak structure and out of square is the binding. Binding is hanging up, chewing the gear tracks, rubbing of the rollers, etc. The bigger the box, the bigger the hole the greater the potential for failures.

I lessen my chances of these failures by not getting large slides, making sure I'm always level before deploying slides, using the manual leveling rather then auto leveling and doing the leveling in small increments rather than all at once. I doubt that any or most RV manufacturers have actual structural engineers and the frame is built to last long enough to have the manufacturer clear of any warranty obligations. The next "generation" of RV buyers will be drawn to the same thing of bling, fancy looking trim and design and not notice the hulks of older RVs with failed structures. Not old like you or me, old like as in your HS or college age kid.
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Old 10-29-2021, 02:19 PM   #68
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e rig in this condition and the slide went out and in perfectly in override mode every time...
To me that is another evidence we are not talking about structure problem but a slide system choice problem.
...
If the structure is so great, why do you think the slide was regularly binding? ...
The bigger the box, the bigger the hole the greater the potential for failures.

I lessen my chances of these failures by not getting large slides, making sure I'm always level before deploying slides, using the manual leveling rather then auto leveling and doing the leveling in small increments rather than all at once.
I doubt that any or most RV manufacturers have actual structural engineers and the frame is built to last long enough to have the manufacturer clear of any warranty obligations. The next "generation" of RV buyers will be drawn to the same thing of bling, fancy looking trim and design and not notice the hulks of older RVs with failed structures. Not old like you or me, old like as in your HS or college age kid.[/QUOTE]


If the structure is not robust ENOUGH, why the other slide (not a small one at 11ft long) doesn't have a problem???
yes, It is a bigger hole in the wall but I can climb in the roof and stand right on top of that hole in the wall and the roof doesn't give... Thats 200 lbs right in the middle of a 24ft opening!
If manufacturers don't have actual structural engineers they should and the software to evaluate structure performance under load is not expensive. Either way, I never heard of structure failure on Thor MH (I have in towables).
In my MH I think the structural warranty is 6 years...
Long enough? I agree not but what vehicle manufacture is giving us 6 years of structural warranty???

I never had a motor chewing the track, etc.
Everything I have ever had was the slide control module cutting the power to motor number 2 because it detected high current draw in the motor.
When the module sent full current to the motors (override), the system worked fine (30+times) w/o chewing any rack, which means the interference was big enough to trigger the module safety but not big enough to make the scwintek system to fail structurally, and that with the system installed out of spec. at the factory...
My beef with Thor on this is that , according to my experience, the system (Schwintek + FWS) is marginal... That is the reason it randomly fails and why , in my opinion, we need a more robust slide mechanism... (Vroom?)

I fully agree with you on your procedure ref. leveling, manual, etc but one thing we love in RVs is the opposed slides and the space it give us inside, to the point that we will deal/fix this and if by the time we decide to buy another one, having a FWS will be on the "must have" features... Maybe I would look at other manufacturers if Thor keeps offering Schwintek but FWS is great (at least for us.
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Old 10-29-2021, 02:55 PM   #69
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Quote:
Originally Posted by RACarvalho View Post
With a shorter rig your should have less/no problem with the twisting we are talking about.
Do you use auto leveling?
If yes, I would manually level, then deploy the slides, then correct the level again manually, then reset the zero point in the auto level.
That should put the auto level at the right zero point.
In my previous rig , a pull behind, I had set the side with the slides 1in higher than the other side so when the slides where out the camper would be level side to side...
I have the Big Foot aftermarket manual (Platinum) leveling system - installed at the Big Foot HQ.

That is essentially the plan - but done manually. The jacks are somewhat jerky when starting/stopping their movement. Therefore, I want to avoid moving them anytime the slide is extended.

I'm going to use a trial and error approach:
First, level the coach with the slide IN.
Then extend the slide and re-check for level.
If NOT level, bring the slide back in BEFORE adjusting any jacks.
Rinse/repeat until the slide is level with the slide extended.

Yes, somewhat of a PIA... but by doing this I can find a perfect level setting WITHOUT jerking the "somewhat" unsupported slide structure.
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