New Motorhome Project -- Looking for Comments/Suggestions -- LONG

[Duff]

Apologies in advance for the super-long post...

I've finally decided to post some of what I've been thinking about for quite a while now. I've been tinkering with AutoCAD layouts, spreadsheets, etc. trying to come up with a workable motorhome design. I'm certainly not the average full-timer, being single and 26. Right now I have a 1991 34' Safari Serengeti that, while adequate, has its shortcomings. I want to stick with a motorhome setup, since I'm generally in one place for several months at a time, commuting and taking regional road trips (I average about 25k miles/year in my car, 4-7k in the motorhome), and would like to still have a practical, fun car to drive.

What I like about the Safari:
<UL TYPE=SQUARE>
<LI> Kitchen layout – I think the L-shaped kitchen layout and side hall is very functional. It feels like a normal kitchen, and I have a decent amount of clear counter space.
<LI> GearVendors overdrive—with only a 3-speed transmission, this thing is essential. I won't go into the mountains anymore if it isn't working, as speed/power on the way up is much improved, and controlling descent speed is much easier.
<LI> Cabinet construction – all solid wood, it all still looks good after 18 years on the road. The countertops were pink tile when I got it, but the cabinets were modest designs that still look good.[/list]
What I don't like:
<UL TYPE=SQUARE>
<LI> Storage bays – they aren't that big to begin with, and are made worse by doors that are only about 2/3 of the bay height. It's difficult to make use of the full space with any sense of organization.
<LI> Narrow walkways around bed – less than 12” in a couple of places, it's tough to walk around to the closet (rear) side of the bed, especially if the TV is pulled out.
<LI> Living room size – typical of any motorhome without slides, the footrest on the recliner gets cozy with the feet of anyone sitting on the sofa.
<LI> Powertrain/chassis – It's an Oshkosh 18,000-lb chassis with a Ford 460. While the 460 is pretty good at making it up hills (~5-6% grades at ~45 mph), it drinks gas (my average over ~3 years is just over 6 mpg). I generally cruise in the 60-mph range, but would like the ability to go faster if I need to get somewhere—this thing really can't maintain anything over 65 in normal conditions. It's not too bad to work on, though getting at engine mounted accessories is a nightmare.
<LI> Wall construction – I knew going into this motorhome that it wasn't going to be very energy efficient with the wall thickness. What I didn't realize until I dug in at the front cap to repair a water leak was just how little structure there was. Very thin walled aluminum tube, and poor welding.
<LI> Closet – somebody had to have mis-measured designing these. The closet is about 2 inches too shallow for normal hangers, so everything gets caught when you open/close the doors.[/list]What I'd like to build:
A solid, reliable, 2-axle motorhome conversion on either an MDT or HDT chassis. I'm thinking a target weight rating somewhere between 30-33,000 lbs, with two (maybe only one) living room slide-outs and a “slide-up” at the rear. To keep the overall length reasonable, and maximize living space, the pop-up over the bedroom allows placement of the bathroom essentially under the bed (I'll post a layout once I figure out how).

Right now (design iteration #43), I'm looking at a ~30' box, with an overall height of just under 13'. To fit it all together, I'm looking at elevating the main floor level above the frame rails, and keeping the roof flat using basement A/C (mini-split HVAC units??). This means that, from the top, the first 6” from the highest point is ceiling structure and insulation, then 7' to the main floor, 4” for floor structure, and about 25” to the top of the frame rails. Of course, one of the advantages in doing this is that I end up with very tall storage bays underneath. I like the idea of a clear “tunnel” above the frame rail for flexibility mounting batteries/water tanks to fine-tune weight balance.

I would plan to put the entry door at the main floor level, with a slide-out exterior staircase similar to some that I've seen online (this forum and others). Where it gets interesting is aft of the wall separating the kitchen/entry from the bedroom/bathroom. I've been through a bunch of different approaches to figuring out how to maintain access to both sides of the bed on the upper level, and to the bathroom at frame-rail height. I'm looking at something kind of weird at this point, but see if it makes sense: the hallway from the kitchen meets three steps up to the passenger side of the bed, passing steps down to the bathroom level at the foot of the bed. To get to the driver's side of the bed, you actually go down to the bathroom level, then step up after passing the bathroom door (this probably makes a lot more sense looking at the drawing). I like the fact that this gives me a full wall of storage space (tall), and I can put a washer/dryer right outside the bathroom door, almost directly over the rear axle.

I'd like to build it myself, but would be open to someone doing the exterior work for me—make it bare-bones livable, then work on finishing the inside.

I'm open to (and would welcome) comments/questions on all of this, and specifically have a few questions:
For something like this, what should I be looking for in terms of horsepower? I see a lot of MDTs that should be able to handle the weight fine, but only ~200 hp. Is that adequate or will I be dissapointed?

Should I be concerned with the difference between 19” and 22” wheels? I notice a lot of the cab-forward trucks have the smaller wheels. Not sure whether I want the complications that come with cab-forward/COE, though it would save length.

Is there a good online source of cab drawings, dimensions, etc.?

Wow. I sat down to make a few quick notes and ended up writing all of this. Thanks in advance for the help, drawings to follow soon.

David

[Duff]

Here's a quick look at the main level and driver's side:



And the lower level and passenger's side (yeah, half of it's upside down):


The elevation drawings aren't fully up-to-date with the floor plans, they're more for reference while moving stuff around at this point.

[geofkaye]

...solve your storage problem with a trailer that you can tow with the MH and the issue of storage is not a problem anymore....tow it or leave it behind under lock and key. It will be cheaper and more beneficial than jacking the coach on the frame....the lower your coach sits the cheaper it is to run-insure-and drive....a 6X12 enclosed will be cheaper in construction/purchase costs if it is too big skip down to the 6X8 or even a 4X6 and give you 10X more storage space than your design. the first question is do you have $50,000 to start?...and can you come up with another $10k along the way for improvements/changes.....geofkaye - The Rivercity Group

[Duff]

It's not that I'm really short on storage--I have a lot of storage space that just isn't very functional. If I had to guess, half of the basement storage is empty space (the bottom of the bays is about 6" below the bottom of the opening, which is only about 10" high), and I have several cabinets inside that are empty largely because they are hard to get to (like the ones under the nightstands, and overhead ones in the bedroom). The other problem with towing a trailer is dealing with the car (the trailer starts getting pretty big).

I think I'm aware of the cost of construction--I was actually somewhat shocked earlier this week when I compared blizz's list to my own. I expected to find guesses where I was way off, or things I had forgotten, but ended up pretty close (except where the designs are obviously different). Of course, I'll probably multiply my final estimate by 1.5 or 2 in figuring out how much cash I'll need. The harder estimate is the amount of time it will take...

[geofkaye]

...I thought you were building a MH and not a trailer....anyway if there is any storage space that is unused it is the fault of the designer....the builder can only build what the designer specifies....and as we all know-the designers are smoking crack most days in the cookie cutter shops-which are now out of business. an inventory of what you take along is a good place to start with a cubic foot measurement...building storage just to have storage is not good design or use of materials/labor-haven't we all seen that in commercial unites....weight is another issue just important as is cubic feet and storage area....I got a guy that wants to have his 3000# Snap-on tool roll around in his trailer "for his tools"....guess what?-he needs a stronger trailer frame-the structure of the trailer is adequate for the storage....but not the weight!......geofkaye

[Bob86ZZ4]

I think it sounds kind of cool. You've got to figure out the power/weight thing too. My rig is 25k lbs. It's just the right power. It pulls my 8k lbs enclosed car hauler with ease. But, I wouldn't want less power. 30k lbs is close on single screw. I'd consider maybe going twin screw. Especially with the length you're thinking. You'd have to have a ton of overhang on the back to keep the front end light enough wouldn't you? I don't know much about this stuff tho. Keep tossing out ideas too. Once you make the final decision it's hard to make changes.

[blizzardND]

Duff, welcome to the forum, I think I might have some insight on this, having learned from the school of hard knock, where they don't give grades, just invoices and bills. While my truck is't as big as yours it is a bit more compact which causes more problems then building big.

Big is easy, it is way easier to run lines and hook up plumbing when you can reach it sitting in the storage boxes rather than tight spots like mine. Chuck at C & S has a truck almost your size maybe a bit bigger that is at the stage you could finish the interior yourself, he wanted 50K for it which would be a real steal.

My bill list that I posted did not include a s&^tload of labor. Buying an incomplete truck would save you a fortune.
-blzz

[geofkaye]

....Duff....2 things:...blizz has the scars to prove his experience and will be a great asset to you on your build....he is still bleeding from the experience so to speak. the other thing I want to suggest is since you are in "knockersville"....run over the I-75 loop to exit 374 or so to a guy that does a lot of country singers and other fools[oops!] he can steer you into some great deals....he and I are not even close friends anymore but he will give you a lot of info-for free!...He has a large number of buses and other motor-homes on his lot viewable from I-75 just outside of downtown on the south bound side....he wouldn't appreciate me using his name[ but my old dog and he have the same first name[Buddy] and personality....'course the dog is dead and so could he might be as I haven't stopped lately to make fun of his dog an pony show[oops again!] Don't mention that you have ever heard of me as he is temperamental about the past-cuz I cleaned his clock on a few deals and still has a lot of resentments so to speak....and no sense of humor when he hears my name whispered in his ear by some young Chattahoochee chick that hang out at the bar just up the street from him on I-75......[oops again and again]......He is the best in the Prevost line IIRC and can put deals together for the C&W folks that want to spend a pile of "C-notes". [Though most lease the coaches and write the whole thing off as a business expense] I have sort of extended family "in the hills&hollers down there" and they sell Mercedes stuff and scratch at the ground to make things livable in the mountains....so to speak.... the ghost of days gone bye.....

[Duff]

I'm actually driving from New Mexico to Knoxville via Huntsville--so I'll have to keep my eyes open on the way up 75. Never noticed the place before...

After driving from New Mexico to Huntsville in the Safari, I'm getting more serious about making a move to a truck conversion. After a not-so-easy climb up to Mt. Magazine State Park in Arkansas, my GearVendors overdrive started to act up. It started to shift a little slow, and periodically shifted out of overdrive on its own for a few seconds. I've had it shift on its own before when a connection worked loose, but the slow shifting was a new one. Later on, it started to leak fluid--not terribly fast, but enough to splatter my car. After climbing underneath to add fluid a few of times (in 90+ degree heat), I'm afraid I'm going to have to pull it out and have it rebuilt.

Here are a few more questions:

<LI>Does any one know of operations building shells to spec? I'm talking about just walls and roof, no wiring, plumbing, etc. Ballpark cost for something like what I'm talking about (not including truck)?

<LI>Bob's comments about how much his conversion weighs have me thinking my initial guess was a little high. I'm pretty sure I can get the CG of the conversion close to where I'm putting the back axle with a ~10' overhang (similar to what my Safari has now, but higher off the ground). All of the water tanks, generator, HVAC, and batteries have space behind the rear axle, the kitchen and bathroom are effectively offsetting each other, and there isn't much weight in the living room. Does this sound reasonable? I'm doing more detailed calculations in a spreadsheet, but have a lot of guesses in there.

<LI>I've read some of the older discussions on here about COE trucks. Has anyone thought about any of the import LCF trucks (e.g. UD 3300, Isuzu F-series)? The challenge would be the pass-through, I think, but I was wondering about the possibility of designing a structure similar to the overhangs on class-C RVs, but making it tilt with the cab and using the space to provide headroom to climb up to the RV floor level.

<LI>Does anyone see any real difference in where you can go with a 12' overall height versus 13'? It seems like most of the Renegade-type truck conversions and a lot of 5ers are ~13'.

<LI>Has anyone built their conversion on the shop floor and installed it whole when finished? This would give me some extra flexibility--e.g. getting started before finding the perfect truck (or working while someone is lengthening frame), using truck to go get materials.

Thanks again--David

[Bob86ZZ4]

Well, this is an old thread. I think Duff found a used Truck Conversion that suits him pretty well. And I'll bet it cost him a lot less than building one.

[blkgld]

Hey guys. I was thinking of doing a build and would like to have Duff's questions answered if possible. Is it possible to build the box on the ground before find the perfect truck. All opinions are much appreciated. Thanks

[hot rod]

A few of the folks here on the forum have built the box off of the truck and then installed it later. Myself and some of the others built it right on the truck.

I don't see a problem building on the ground when you have the truck right there for measurements, but I would worry about trying to do it without the truck there. Some things are pretty standard, like the frame rail width and spacing, but other things vary like the height of the cab if you are thinking about an overhead bunk. Or the wheelbase of the truck you find may affect how you decide to build, unless you are planning on having the truck stretched or shortened to match the box you build.

Just thinking out loud. Good luck with the project.

[Kenn]

I built my motorhome in three phases. Phase 1, I did mechanical upgrades to my 1982 truck and added six feet to the frame. I added a 50 gallon LPG tank and leveling jacks. I also had the front drive axle removed and new drive shafts built. Phase 2, I built the lower unit on the truck. My lower unit includes the compartments, water tank and holding tank. Phase 3, I built the living unit in my shop (looks like a big truck camper) and had if lifted onto the truck with a crane. After the crane put the living unit on the truck I welded the upper to the lower units and now I am working on the interior of the living unit.
Everyone that builds a T/C has a lot to think about. I built mine off the truck because my home shop has a 10' door. The truck without the stacks will clear and the living unit about 9' on casters cleared. I had to use 2" x 2" tubing for the floor braces on the lower unit and 1" x 2" for the floor of the living unit and then weld them together later. I agree with Hot Rod that building without the truck would be hard. Finding room to place all of the systems under a box is hard when you have the truck and I think muck harder without the truck but it could be done. On the plus side when I built the upper unit I could reach everything off an 8' ladder. One piece of advice I would give is to take your time finding the right truck and if it seems like a lot of $$$$ for the right truck that amount will shrink compared to what you will spend on the rest of the project.
When I started, Blizz advised me to find a used T/C and save a lot. He was right but I can't tell you how much I have enjoyed building my own version (for better or worse) of a motorhome. The time and money it takes to build one is BIG.
Good luck and asking a lot of questions is free.

[Duff]

Wow, Bob!

I didn't realize it had been that long ago! Those plans were just starting to get going--they've been through a million revisions since then, and have quite a few more to go. When I bought my current truck conversion, it was needing some work (on the RV part, not the chassis)--I thought at the time that I might re-do it to get the layout I'd like. Two years later, it's in good enough shape that I'd hate to rip it apart, especially the stuff that would n't be reused (like the solid oak woodwork). So anything custom I do would be starting from scratch.

Four years later, I can probably answer some of my own questions, and update my list:

The GearVendors Overdrive lives up to its claims about not leaving you stuck. After it quit working, I drove another 1,000 miles or so just fine. When I replaced it (30-minute job), there were all kinds of big metal pieces in the pan, yet it still transferred power through in 1:1 mode.

I wouldn't be happy with an MDT with 200 hp. The 475 hp I have now seems about right. I definitely like the Freedomline transmission so far as it's the only one from the early 2000s that skip shifts (often I hit 3,6,8...). Newer Ultrashifts and the i-shift do the same thing now, so any of the automated manuals would probably be fine. They're all going to be slower off the line than a true automatic though.

I don't think--at least this size range--that there's any big reason to try to single the rear. You'd get a little more storage space, and pay a little less in maintenance and tolls, but that's about it. Tandem there's really no worry about weight, towing or not.

I haven't really encountered anywhere where my height has been an issue. Same thing for overall length. I would have a little shorter wheelbase though--generally I think I'm more limited by breakover angle than rear overhang (neither is much of an issue), and a little tighter turning radius would be nice. I would gladly get rid of the roof A/Cs for another foot in baggage bay height, but I don't think anyone offers such a system anymore.

Some ideas seem to be cyclical, as the COE conversation popped up at the HDT rally last week. I have a decent idea for how I'd mate cab and box, but they're far more difficult to find in decent shape now than they were 4 years ago. The only practical way (and that's a stretch) to do this would be some sort of import operation or Argosy glider.

I really like how Showhauler (what I have now) and a few others construct their boxes, with a welded steel cage constructed first and everything attached to it. I've seen pictures of one after a rollover accident, and it fared quite well. My only complaints are the exterior panel attachment (which seems to be hit-or-miss), and the fact that the roof is completely flat--water tends to pool, especially with the lip where the roof meets the corner/side moldings.

I'm sure what I have cost me less than building one, but it just hasn't satisfied the urge to do it anyway!