Convert Your ‘Pavement Queen’ RV Into A Mean Off-Road Prepper Machine

Part One – Suspensions/Tires 

Factory leaf springs compressed nearly flat due to max loading of payload 

By the time my wife and I reached Provo, Utah I was already disenchanted with the 5^th wheel RV that we had recently purchased. But maybe I should back-up just a little and start at the beginning…

Since about January of 2014, I had been contacted by numerous TV producers looking to cast me into yet another Doomsday Prepper style show. And in listening to the ‘pitch’ as to ‘why I should’, it became obvious that these producers were all essentially doing ‘more of the same’. I had to ask myself; why would I want to do more of what has already been done or which will amount to just another ‘me-too’ show?  But these calls were a catalyst for me, and I started thinking about what would audiences really want in a new Prepper/Survival show?

Based upon my discussions with hundreds of Survivalists and Preppers who have contacted me over the past year since my appearance on National Geographic Doomsday Preppers, I had an idea of what was in demand.  It was clear, at least to me; the studios wanted more cloned shows as a result of the success of Doomsday Preppers (copy what works, right?). But there comes a point when even what is successful becomes tired and boring; audiences clearly want something fresh!

After talking with a friend who is also a producer, I set to work on developing a concept for a show that would check all the boxes; provides usable and practical skills that are fully outlined and entertains like crazy. I finally had an epiphany and put my new show concept on paper.  But it’s not so easy… I had to also solve some of the problems and have answers to questions that any production studio would pose. And one of the many issues was a filming location. I was going to have to do some serious (expensive) leg work and scout potential locations for such a TV series. And these were not your basic ordinary locations; I would have to find and film the remaining wildernesses within the Southwestern United States.

I estimated that I would need to spend at least two months on the road traveling between wilderness locations, as well as spending time at these locations, filming and documenting the pros and cons.  I would need an RV that was up to the task. So I did some basic due diligence after which I purchased a fully self-contained 30-foot 5^th wheel. I also acquired a potent 4X4 pickup truck to pull the 5^th wheel.  So we packed the fifth wheel with all the basics and prepared to head south from Portland, OR; clothes, first aid, food, water, etc… And of course the RV came complete with a built-in fresh water tank as well as grey and black water (sewage) tanks, and even a 32 inch flat screen TV that was WiFi capable so I could review photos and film. Truth be known, the RV had all of the comforts and amenities of home. By the time we had all of our gear loaded, guess what?  We were a little overweight; maybe even more than a little.  When I asked other RVers about this, they almost unanimously said’ “who isn’t”? The factories (pretty much all of them) send RVs out the door with minimal usable payloads.

As I learned, most on-road problems come from suspension and tire failures due to overloading. The useful payloads of most factory RVs are in fact so minimal that some RVers I talked with don’t even travel with their fresh water tank full, and instead fill them when they arrive at their destinations or nearby. Most RVs in the 30-foot class have 40 gallon drinking water tanks, which when full add about 320 more pounds. What Prepper or Survivalist would travel without an adequate water supply onboard at all times? None that I know of…

So fast forward again to Provo Utah: There are not many things that give me ‘white knuckle’ syndrome… but I have to say, coming down the steep grades out of the mountains in a cross-wind pulling that overloaded 5^th wheel with a stock suspension and tires was a new experience!

When we’d hit a long sweeping corner at 60 mph, or a gust of wind would hit the side of the rig, it would lean over a bit, and that in turn would cause the rig to start to fishtail, albeit less than a bumper-towed trailer. This ‘leaning’ on curves or in high winds caused the leaf springs on the side being compressed to change their length; a leaf spring has an arc in it, so when it compresses flat it gets longer… let me explain. This is a little technical, but I promise I am getting to the good stuff  J …

The old 6,000 lb. tandem axle setup off our 5^th wheel

 On a tandem axle rig (like ours), you have two axles, one in front of the other. The springs are bolted to the axles using U-bolts. Each axle has two leaf springs (one on each end) that connect to the frame. So on each side of the tandem axle trailer (in this case) you have one spring in front of another (on a triple axle rig, you would have three leaf springs in a row on each side).

Basically, as the trailer leans (on curves, in cross winds, on side hills) the springs compress, but not all of the springs vary their arc’s equally. So looking at one side of the trailer as it leans to that side; when you have one spring in a set of two that is compressed more than the one in front or behind, it becomes longer and the distance between the tires (and axles) on that side of the trailer changes a bit. There is a ‘spring equalizer’ that is mounted between the springs that will take up most of the change in length, but it doesn’t take much change to create a reaction. This variance in the spring length causes tires pull in closer or push apart from each other. And as a result, the suspension geometry on the compressed side is different that the opposite uncompressed side. This can cause the trailer to track off to one side or the other (AKA: ‘fishtailing’).  And when you add any braking-action while you have this asymmetrical suspension situation, it exacerbates the fishtailing condition.

Fishtailing is usually much more pronounced in trailers that are towed from the bumper of a car or truck and is a trait less seen in 5^th wheels, where some of the trailer’s load is actually transferred to towing point at center of the bed of the pickup truck and loaded directly over the towing truck’s rear axle and suspension.

The ‘leaning’ problem was really apparent when I had our 5er (as they are sometimes called) parked on the side of a hill; I looked under the rig and I could see that one leaf spring was compressed more than the other on the same side. This was likely due to the fact that there was more weight on one part of frame as a result of uneven loading.

It’s important to note that it’s nearly impossible to load an RV trailer evenly side to side and front to rear. Most RVs have water tanks, built-in furniture, appliances (refer, stove, hot water heater, etc.), batteries, propane tanks and all the stores and equipment you bring onboard. The factories try to balance the trailer design, but there are too many new variables when they are loaded and used in the real-world.

I pondered this suspension issue as it related to the ‘net payload’ of the RV. Looking at the vehicle weight placard, the difference between the ‘net’ vehicle weight and the ‘gross’ vehicle weight allowed for a very limited payload. And it was obvious that the factories hadn’t designed the suspension to carry the kind of gear and supplies needed to go totally off-grid (AKA: ‘Dry-Camping’) along with everything else related to a full ‘off-grid’ conversion (water purification, solar, special batteries, inverter, etc.). I found myself maxed-out on available payload, and I was already designing additional ‘off-grid’ add-on systems (part-two of this series) such as a solar-battery system complete with inverter that would add even more weight!

Tires, wheels (fancy alloys with 2 inches of offset), hubs (6-lug nuts) and axles before conversion

If I was going to ‘Prepperize’ my RV, the first order of business was to beef-up the entire suspension. I began this process by having several teleconferences with the design engineers at the factories; RV factories, chassis factories and axle factories. The frame in our rig was the same one used in rigs longer (heavier) than ours, so it was up to the task of a heavier payload.

After analyzing all of the information, it was obvious; you can’t just change the springs. I would need to upgrade my leaf springs to carry the additional load as well as my axles. The axle upgrade was important because if you load the rig heavily, that required the bigger bearings in the heavy duty axles. And of course, the tires and wheels would need to be upgraded as well… no weak links!

The Application Of Theory:

The next challenge was; where could I get my newly designed suspension properly installed, and who was qualified to do this work? Even though I am a mechanic with years of experience, given the liability and risk of any modification to any RV, I felt (and advise others) that it would prudent to have RV specialists make any intended modifications.   By the time we arrived in Flagstaff Arizona, I was more than anxious to have the upgrade…

The finished rig with the excellent team at Flagstaff RV Sales & Service

I started asking questions around town and found a consensus as to the shop I should use; Flagstaff RV Sales & Service in Arizona.  They are a family business and have been in business since 1979. The current head-honcho is Chad Thornsley (seen far right in photo above). Chad grew up working at the family business fixing all aspects of motor homes and RVs. When I talked with Chad and his team it was clear they knew their trade inside and out, and within an hour of bringing my project to them, they had already ordered all of the correct parts needed, at fair prices. The following morning the parts had arrived and by the end of that same day, my 5^th wheel had been converted from a ‘pavement Queen’ to a mean off-grid Prepper machine (at least suspension wise; the rest will come later).

Suspension – Leaf Springs:

The factory 6K lb. axle above came with 4 ‘leaves’ in the spring

My 5er came from the factory with 4-leaf stack leaf springs, each rated at 3,000 pounds for a total of 12,000 lbs.

Upgraded 5-layer leaf springs rated at 3,500 lbs. each; total of 14,000 lbs.

We ordered 5-leaf stacks, which were rated at 3,500 pounds each, which increased the total spring suspension capacity from the factory 12,000 to 14,000 pounds! This would increase my net payload capacity by about 2,000 pounds!  And that is more than enough increase to handle the existing weight issues and also handle the weight of the additional upcoming off-grid preps with a safety margin.

The upgraded Dexter link (left) is significantly stronger than the factory link (right)

In addition to the upgraded springs, I opted for the Dexter suspension kit, which included heavy-duty spring links, spring equalizers and bronze bushings with zerk fittings for grease.

Suspension – Axles:

My 5^th wheel came with tandem 6,000 pound axles, which together matched the ratings of the stock leaf springs at 12,000 pounds. My axles were ‘over-slung’, which means the springs are mounted on top of the axles. This provides the greatest ground clearance under your rig, especially when you upgrade the wheels and tires to a larger diameter (more on that a bit later).

New 7,000 lb. Dexter axle; preparing to weld-on the ‘over-slung’ spring seat

We upgraded the axles to 7,000 pound Dexter axles, for a combined rating of 14,000 pounds, matching the upgraded springs. The 7,000 pound axles have slightly larger spindle diameters and much larger outer wheel bearings (the smaller of the two bearings in each wheel hub) than the old 6,000 pound axles. Here again, we picked up 2,000 pounds in additional rated carrying capacity! There was a visual give-away to this upgrade; the wheel hub on the old 6,000 pound axle used 6 wheel studs and lug nuts, and the new hub uses 8 studs and lug nuts to secure the wheel to the hub.

Suspension – Tires:

A lot of people get into deep trouble when it comes to tires… tires are not all created equal. Tires may be the single weakest link in the whole suspension equation if they are not properly matched to the suspension. It’s pretty common to hear RVers talking about ‘E’ rated trailer tires as being the best… they are not. Many ‘E’ rated trailer tires also say ’10-ply rating’, which doesn’t necessarily mean the tire actually has 10 plies!  I dumped my brand new ‘E’ rated 16 inch tires and wheels and went to the super heavy duty 14-ply Goodyear ‘G’ rated trailer tires. These tires are the best there are in my opinion. The rubber that meets the road is so thick in fact, that when the tread wears off, they can be safely re-grooved! No kidding!

They also run at very high air pressure; 110 PSI. In all fairness, I should also mention that Michelin also makes an excellent trailer tire (the ‘Rib’) which is also ‘G’ rated, but to my knowledge cannot be re-grooved. It is also taller by about an inch (in my application compared to the Goodyear tire of the same size), so on a tandem axle setup (like mine), two Michelin tires will not have the recommended clearance between the fore and aft tires.

Suspension after total conversion: 16 inch Dexter ‘0’ offset wheels with 14 ply Goodyear tires

Suspension – Wheels:

Of course in order to properly use the new Goodyear tires on the heavier axles, I needed to use heavy duty wheels that would accommodate the added weight and tire pressure, along with fitting on the new hub with eight wheel studs. You cannot mount a 110 psi tire on just any rim; I have heard that at high pressure some wheels will fail (big difference between 80 psi and 110 psi). I went with the steel Dexter wheels for a couple reasons: First they are rated to match the upgraded load capacity of the new springs, axles and tires.

And secondly, for a very important reason; a reason that few tire shops even know about; the wheels that must be used on almost all trailer axles must have ‘zero’ offset (Dexter trailer wheels have ‘0’ offset). Zero offset means that the load is absolutely centered over the wheel bearings. Many of the fancy alloy truck wheels that will fit on trailer axles have some offset and that offset places significant additional loads on the wheel bearings, effectively reducing the load-rating of the axles! Using offset wheels on trailers can lead to a catastrophic failure! Don’t make that mistake… check your wheels!

The improved ground clearance under the 5^th wheel trailer is now better than the 4X4 truck

On many rigs with tandem or triple axles, the spacing between the axles (and tires) is such that you can move up from a 15-inch wheel and tire to the 16-inch wheel and tire, without having the tires too close together. This, in addition to having over-slung springs on your axles will increase your rig’s ground clearance (the combination is best; larger wheels and tires and over-slung axle springs)

The Results:

It’s hard to express in words how it feels to pull this 5^th wheel trailer after all the upgrades, but I will try.

1. Tracking in heavy winds: Our 5er now tracks like it’s on rails, even in the gusty spring winds here in the Southwestern Mountains and deserts. We recently made a 200 mile run in cross-winds that were sustained at 35 mph, with gusts to 50 mph. The trailer was as steady as a rock.

2. On sweeping 65 mph curves: Here again, the trailer felt super stable, instead of feeling like it might break loose at any moment. The new heavy duty tires didn’t look like they were trying to roll off the wheels due to the side loading. And while we are talking about those big high speed sweepers; can you imagine having a blow-out on one of those curves? I have talked with a man who lost his rig, and lucky not his life or his truck when he had a blow-out on a high speed curve doing 60 mph (the speed limit was 75 mph). The trailer careened and rolled off the side of the road, and luckily broke free from the truck. Another man regaled me with a story of a blow-out that caused over $5,000.00 worth of damage to his 5er, more than the cost of my entire upgrade-conversion. As I was learning, these kinds of serious failures were not uncommon.

3. Side-hilling: Our 5er doesn’t lean when it’s on a side-hill; the suspension stays level and the trailer is stable. This allows us to use many primitive roads that the ‘pavement queen’ RVers won’t even think about! And the thick Goodyear tires take the worry out of rolling over sharp rocks in creek beds.

4. Added Benefit: The high-pressure tires actually helped my gas mileage a tad! From my calculations over the past 900 miles since my conversion, I picked up about .3 mpg.  The ‘E’ rated tires run at a max pressure of 80 psi, so they are a bit spongy compared to the ‘G’ rated tires. The new ‘G’ rated tires run at 110 psi, and I believe that they simply roll better as a function of rigidity resulting from the extremely thick rubber tread and high pressure.

5. Ground Clearance: The trailer has no problems passing over the same terrain (rocks, ruts, etc.) as the truck! And that’s really nice and provides a safety factor; if the truck can make it, the trailer can too!

6. Confidence: The upgrades have really taken a lot of the stress out of cruising down the highway at 55-65 mph with a fully loaded trailer!  Just this alone was well worth the price of the conversion! And now when I am in the middle of the mountains (where there is virtually no help and no cell coverage) I am not worried about having a suspension or tire failure.

Now that our 5er has an added 2,000 lbs. in useful payload, we can take the next step and add a super solar – battery package and inverter, which is the subject of the next article in this series.

A safe worry-free trip is a fun trip! Even if you’re not going off-road, having a blow-out or suspension failure on the highway (let alone in a remote location off-road) is a real bummer in the best case, and can be a serious life threatening event in some cases. Why not stack the deck in your favor?

Stay safe and have fun out there!

Cheers! Capt. Bill

Capt. William E. Simpson – USMM
http://www.WilliameSimpson.com
Twitter:  @NauticalPrepper

Important notes/disclaimers: Do not modify any RV without the proper engineering and installation oversight. Also, as I learned, any modification of any RV under warrantee will usually void the factory warrantee (consult with your RV’s manufacturer before making any modifications to any RV). Most warrantees aren’t that long (a year or two) and they almost never extend to the second owner of an RV. Improperly engineered modifications can be extremely dangerous and may cause property damage, injuries and/or death. Readers are advised that any such modifications as suggested or outlined in this article are done so at the sole and exclusive risk of the reader. The author and publisher of this article make no warrantee or representation as to the suitability or fitness of any advice provided herein for any purpose.

Convert Your ‘Pavement Queen’ RV

Into A Mean Off-Road Prepper Machine

By: William E. Simpson © 2014 All Rights Reserved