Itasca Class C Overhang Movement

pnichols wrote:
I'm beginning to believe more and more that leaking forward facing clearance lights may be causing a lot of the cabover wall/floor rotting that folks are seeing, which can affect all cabover designs - one piece fiberglass included.

You are absolutely correct on this point. Marker lights leak very often. It is unfortunate that the manufactures of those lights don't offer a better product. Some come with gaskets that either are not installed with care or don't last. The manufacture of our rig caulks around each marker light to assure no water gets inside.

pnichols wrote:

Farmboy666 wrote:
Thanks Ron for illuminating my disillusion on my overhang movement.

Ron ... I think he may have meant to be a little sarcastic, because in an earlier post he stated that he hadn't seen any movement in his cabover.

Looking again at the diagram of how Winnebago has designed their Super Structure metal bracing in the cabover sidewalls, I don't see how the cabover sidwalls can move up/down relative to the coach unless the cabover metal struts are flexing/bending or their welds break. I just don't see how the cabover sidewalls - with their metal struts - can move up/down relative to the coach walls, with their internal metal framing.

I don't agree that the vertical steel struts in the cab walls aren't going to be able to help restrain the bottom of the cabover from moving up/down ... unless the bottom of the cabover (which has no metal in it) is heavily rotted out. It may have been the rotted cabover bottom that the OP saw flexing up and down due to road vibration, airflow, etc. ... not the whole cabover itself.

By the way, I'm beginning to believe more and more that leaking forward facing clearance lights may be causing a lot of the cabover wall/floor rotting that folks are seeing, which can affect all cabover designs - one piece fiberglass included.

Not sure which one of us doesn’t get sarcasm.

The area I see moving is the lower sidewall on drivers side around the corner moulding. It appears to just be the very end of the overhang

Farmboy666 wrote:
Thanks Ron for illuminating my disillusion on my overhang movement.

Ron ... I think he may have meant to be a little sarcastic, because in an earlier post he stated that he hadn't seen any movement in his cabover.

Looking again at the diagram of how Winnebago has designed their Super Structure metal bracing in the cabover sidewalls, I don't see how the cabover sidwalls can move up/down relative to the coach unless the cabover metal struts are flexing/bending or their welds break. I just don't see how the cabover sidewalls - with their metal struts - can move up/down relative to the coach walls, with their internal metal framing.

I don't agree that the vertical steel struts in the cab walls aren't going to be able to help restrain the bottom of the cabover from moving up/down ... unless the bottom of the cabover (which has no metal in it) is heavily rotted out. It may have been the rotted cabover bottom that the OP saw flexing up and down due to road vibration, airflow, etc. ... not the whole cabover itself.

By the way, I'm beginning to believe more and more that leaking forward facing clearance lights may be causing a lot of the cabover wall/floor rotting that folks are seeing, which can affect all cabover designs - one piece fiberglass included.

Howdy, spent a lot of time thinking about this. My 2003 Winnebago Mini 24v does move a little. So did my 94 Tioga , but it had a steel frame that was rusted through when I rebuilt it. That's why I was so happy to find out the Winnie has an aluminum frame. My 73 Tioga and 73 Gladding Del Ray did not move at all. They had steel frame but not rusted as bad and much thicker flooring up in the cab over area. I have seen a class C with a bars from the cab over down to the front fender (some kind of a flange mount) and wondered if they really help.

For those who don't think a cabover can flex, this one could be moved by just pushing on it before it was torn apart. :E

Farmboy666 wrote:

ron.dittmer wrote:
Anyone who says their front over-hang does not move is either in denial, or has never hit a pothole or equivalent road imperfection with one of their front tires. Heck, even the cab and hood flexes hitting something serious. Things move, most especially your front over-hang. If you don't experience it yet, give it time. The perfect storm of road imperfections will come your way.

I did my first engine rebuild at 18yrs old, I have been building houses for 40 yrs. I know a little bit about cars and structure. Thanks Ron for illuminating my disillusion on my overhang movement.

You are welcome.

That is why I post this now and then for people who are shopping for a class-C motorhome.

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New, used, or well used, when shopping for a conventional class B+ or C, the most important consideration is how it is constructed. This post outlines construction methods which are most affordable and methods that cost more, but are built to hold up much better to the elements and also the punishment of the road.

Some motor home manufactures offer different levels of quality through their various model lines. Instead of providing a list of brands to consider, it is best to identify what "Better" is.

When shopping for a motor home, don't get distracted with "Eye Candy" and "Square Footage". You want to pay close attention to how the house is constructed. Water infiltration is the number one killer of motor homes, rotting them away long before anything is worn out. Once water gets inside, it is like termites. By the time you realize there is a problem, a lot of damage has already occurred. Also consider that mold & mildew can grow inside the walls which then you have a health hazard. My advise focuses on identifying a reliably well sealed motor home.

#1 BEST (Very Expensive, Can Be 1.5 times the cost of Second Best)
NO structural seam work. The brand Coach House is a fine example. It is seamless, made from a mold. The only places where water can leak is cutouts for windows, entry door, roof-top vents & a/c unit, storage compartments & maintenance access, all of which are in areas of very low stress. Because they have a seamless shell, these motor homes are not common and have a limited selection of sizes and floor plans.

#2 SECOND BEST
Common, Affordable, & comes in Many Sizes so this is my main focus
I own an example of this type. My Rig Here manufactured by Phoenix USA.
Made in sections, but assembled in a way that greatly reduces the threat of water damage. Here are the good things you want to look for.

a) Structural Seams Away From Corners
When a motor home is driven, the house bounces, resonates, shakes, and leans countless times, representing a endless series of earthquakes. Corner seams see greater stresses than seams located elsewhere. Corner seams are more easily split, especially when the caulk gets brittle with age & exposure to the sun. One extremely bad bump in the road can instantly breach a corner seam. Seams hold up much better when they are brought in from the corners in lesser stressed areas.

b) A Seamless Over-The-Van Front Cap
A huge bed above the van’s roof is the most vulnerable area of a motor home. No matter how well they are made, that long frontal over-hang resonates when the RV is driven making it common for seams to split there, most troublesome with age & exposure to the elements. HERE is an example, one of many water-damage threads I have read. Scroll down in that thread to see pictures of the real damage.

The small front aerodynamic cap of a B+ design HERE eliminates the overhang which eliminates most of the resonation, along with the most vulnerable seam work.

There are a few conventional “C” Designs (big over-van bed) where that area is seamless. If you absolutely must have that huge bed, then look for a seamless bucket-like design. The Itasca Navion Here is a fine example. Some manufactures as of late offer a partial bucket design with fewer seams located in less-stressed areas. Some manufacture models like the Minnie Winnie and the Nexus Phantom utilize a compromising partial bucket design, making it a better choice compared to a fully seamed cab-over bed.

If you plan to accommodate more than 2 people, having that large extra cab-over bed will be extremely useful.

c) A Crowned Roof
Rain and snow melt runs off a crowned roof. A flat roof will sag over time, then water puddles around heavy roof-top items like the a/c unit. Water eventually finds it's way inside after gaskets & caulk have degraded from age, sun, and change in seasons.

d) Rolled-Over-The-Edge seamless Fiberglass Roof Sheathing
A single sheet of fiberglass as shown HERE that rolls over the right & left sides of the roof, down to the wall. The overlapping of fiberglass to the wall provides a good water seal and the fiberglass sheathing holds up better than roofs made of sheet rubber or thin plastic called TPO, which require more attention to keep your RV well protected.

e) A Five Sided Rear Wall Cap
A five sided back wall moves the seams around to the sides to areas of much less stress as seen HERE. The rear wall resembles a shallow rectangular cooking pan standing on it's side. Like the example, some rear wall sections are constructed with an integrated spare tire compartment and rear storage compartment. Not only are they convenience features, but that rear wall/cap offers a solid double-wall for exceptional strength which is more resistant to flexing the adjoining seam work. It helps in keeping the house together.

Don't be fooled. There are a select few manufactures who add rear wall sectional styling pieces over an entry level rear corner seam design which gives the appearance of a 5-sided pan design. You can easily tell by noting the sections & seams between them and the flat back wall that remains exposed.

Bigger Will Be Weaker
The size & floor plan you select MUST FIRST meet your needs before this consideration.
The bigger the house, the weaker the structure will be. Consider two cardboard boxes made from the exact same corrugated material. The smaller box would naturally be stronger. It will be more resistant to bending, twisting, and other types of flexing. So if you are on the fence between models, the smaller one will be your stronger choice.

Potentially Troublesome Construction
Entry level motor homes are made with seams in corners and finished off with trim, including the massive cab-over bed. Their roof is flat and finished with rubber or TPO. They are most affordable, and come in all sizes. HERE is one such example. If considering this construction type, keep in-mind they require more regular care with bi-annual inspections. Plan to use a caulking gun now and then. When buying a used one, consider that you really don't know how well the previous owner maintained it. Buying new or used, that construction method will be counting on you to be a good non-neglectful owner.

There are also the rare exception of the Lazy Daze which has seam work in the corners, but the substructure and sealing method is of the highest quality that it holds up like a seamless body. It's excellent sectional construction methods are not commonly found in other brands. I am no expert on this, but I'd give it a #1.5 Almost Like Best

About The Chassis
The most popular is the Ford E350 and E450 with the V10 engine. The Sprinter diesel is a popular alternative to the E350 in the smaller sizes. Also within this past year is the recent introduction of the Ford Transit. The GM 3500 & 4500 chassis are not popular but are a very good choice for the right application. Any of the chassis mentioned made since 1998 are real good, new or used. If you plan to tow a car or heavy trailer, be aware that the Sprinter & Transit will be least powered. People who tow with them naturally take it slower.

If considering a current-day “small” class B+ or C motor home, here is a comparison between the two current main chassis contenders, the Sprinter with the V6 diesel engine and the Ford E350 with the V10 gasoline engine.

Advantages Of The Mercedes Sprinter With Diesel Engine
- Offers a 35%-50% improvement in fuel economy over the Ford-V10, when both are loaded and driven identically.
- More ergonomic driver compartment with more leg room.
- Comfort continues with a car-like feel & quiet ride.
- A grander view out the windshield
- Made by Mercedes which people are attracted to.

Advantages Of The Ford E350 with V10 Engine
- Given identical motor homes both brand and model, the Ford is around $13,000 MSRP cheaper
- The Ford V10 engine has 50% more horse power and torque
- The Ford E350 chassis handles 1430 pounds more weight.
- The E350 is able to tow a heavier load.
- The E350 rear axle is significantly wider which translates to better stability.
- In most places traveled, gasoline costs less than diesel fuel
- The Sprinter diesel has limited mechanical service shops around North America
- The Sprinter diesel is typically outfitted with a propane generator. Propane is a critical fuel for RV operations, and generally needs to be rationed when dry camping.
- This Next Point Is Debatable But Still Worth Noting....The V6 Sprinter diesel engine is not allowed to idle for extended periods. This limitation is detrimental when you need a/c but there are generator restrictions, you are low on propane, or you have a mechanical failure with the generator or roof a/c. The Ford offers a great backup system. The V10 can safely idle for hours on end, heating, cooling, and battery charging, all valuable if you have a baby, pets, or health/respiratory issues.

You decide what your priorities are, and pick the appropriate chassis. There are some really sweet motor homes being built exclusively on the Sprinter chassis, such as the Winnebago Navion and View. Others like Phoenix USA build their model 2350 and 2400 on both the Sprinter and Ford E350. They will even build it on the heaviest duty E450 upon request for a nominal fee. People who request an E450 for a small motor home, tow heavier things like for example, a multi-horse trailer. You can even special order a E350 & E450 4x4.

There is so much cool stuff offered in recent years on the Sprinter and most recently on the new Ford Transit.

The Ford Transit Chassis
This chassis has the potential to dominate the class B+ & C motor home market in the smaller sizes. According to Ford's website, the Transit DRW chassis is offered in the 156", and 178" wheel base, and is rated as high as 10,360 GVWR. Ford offers a motor home package specific for the RV industry. It's diesel engine compares to the Sprinter in power and fuel economy, but is more affordable and is easily serviced at Ford service centers, just like the E350 & E450. The cab has a much lower stance than the Sprinter making it much more friendly to get into and out from for people in their later years. It's more like a mini-van rather than a standard van. The Transit's lower cab also offers roomier over-head bunks that are easier to access.

The Dodge Promaster 3500 Cut-Away Chassis
This front wheel drive chassis is another recent entry in the RV industry. I am concerned over it's lack of load capability as reflected with single free-wheeling rear wheels. I have been reading posts written by new Promaster RV owners stating they are over-weight with just two people, some personal effects and food. They say they can't carry water and never a 3rd person. I would not be comfortable with such a limited load range in a B+ or C. This chassis does seem to be a good option in the "B" motor home market.

The Chevy 3500 & 4500 Chassis
Unfortunately this chassis is not more popular, primarily because GM sort-of gave up on competing with the Ford E350 & E450. It offers more interior comfort than the Ford, but not as much as the Sprinter. It's power & weight ratings are a little less than their Ford counter-parts making them a great chassis for all but the heaviest of class Cs. They are also a little better on fuel consumption. One thing to keep in-mind, if you are counting inches in storing your rig, the Chevy is a little longer than the Ford by a number of inches which was critical for us with our garage as seen HERE with our Ford 2007 E350 rig. That could be the reason why the Chevy has a little more interior driver/passenger leg room.

The Ford E350 & E450
The majority of class B+ and C motor homes are built on one of these two chassis for a number of very good reasons. They have more power and load capability than the others. Ford approves outfitters to modify the chassis to increase or decrease the wheel base which supplies motor home companies a lot of design freedom. Ford has off-the-shelf components that work with the wheel base modification. So if you need a new drive shaft, fuel line, brake line, parking brake cable, wire harness, whatever, Ford has them available. Finally, the E350 and E450 chassis is competitively priced.

Engine Power Ratings of Ford, MB-Sprinter, Chevy, and Dodge
Ford E350 & E450 - 6.8L-V10, 305hp, 420ft
Ford Transit Diesel - 3.2L-I5, 185hp, 350ft
Mercedes Sprinter Diesel - 3.0L-V6, 188hp, 325ft
Chevy 3500 & 4500 - 6.0L-V8, 323hp, 373ft
Dodge Promaster - 3.6L-V6 (GVW only 9,300 pounds)

ron.dittmer wrote:
Anyone who says their front over-hang does not move is either in denial, or has never hit a pothole or equivalent road imperfection with one of their front tires. Heck, even the cab and hood flexes hitting something serious. Things move, most especially your front over-hang. If you don't experience it yet, give it time. The perfect storm of road imperfections will come your way.

I did my first engine rebuild at 18yrs old, I have been building houses for 40 yrs. I know a little bit about cars and structure. Thanks Ron for illuminating my disillusion on my overhang movement.

pnichols wrote:
Our 2005 Itasca does not do that. In fact the bottom of the overhang is cut out in a half-circle that is attached to a matching half-circle cut out in the cab's steel roof. By pushing one half of the two-piece overhang bed mattress up onto the forward piece of the mattress when not used for sleeping, we can enter into the cab almost fully standing and only bend down at the last minute to sit in the driver and passenger seats. Our overhang could not bounce or move without tearing itself free from the cab's roof.

Maybe Winnebago changed the whole overhang bottom/cab ceiling design sometime after the OP's model year?

Same thing with our 1976 Monaco Winchester, and that two-piece overhang is really handy, when you're 6'0". I never noticed any movement in our overhang either.

pnichols wrote:
Ron,

????

We've went miles and miles out in the desert at 7-10 MPH on extreme washboarded roads - plus slowly along some just plain ugly tipped and rutted desert road surfaces. For instance and including traveling on the "Not Recommended for RVs" road leading down to the valley floor of Monument Valley right alongside the special jitneys driven by Native American workers taking tourists down there.

Our overhead cab bottom cannot move relative to the cutout cab roof it's rigidly attached to without ripping or distorting something in that area. In fact, the cab-roof/cabover-bottom interface logically should be designed such that the steel cab roof structure helps to rigidly support the overhead structure so that it can't flex up or down on it's own. From what I can see the two are designed to be joined together and remain together as one structure. In our Itasca Class C there is no distortion or deformation in that area after after 12 years of ownership on and off smooth roadway surfaces.

In a Class C the proper marriage of the coach structure to the chassis frame - relative to the proper marriage of the cab structure to the chassis frame - is a whole different situation from the relationship between the two separate structures that exists when a slide-in truck camper is held down by 4 to 6 tie-downs while riding in the wiggling bed of a pickup truck.

Of course, we don't store hundreds of pounds of stuff in our Class C's cabover bed when traveling either - as the bed has to be handy to be used every night for sleeping - but the person (me) sleeping in it does weight over 220 lbs.. :)

Chances are very good that the side walls of your RV are quite similar to those of this 2001 Itasca 31 C Sundancer. The frame can break from the stress, as this one did. There is not that much strength in the cut out van cab roof Everything depends on keeping water out and preventing rot.