Down the Rabbit Hole into GCWR, Tongue Weight, Load Balancing and They Weigh HOW Much?

Have House Will Travel


I really like the idea of being able to pick up and drive away, and not leave anything behind. Like a turtle with your house on your back, the wanderlust in me makes tiny houses on wheels a very attractive prospect. It was natural for me to look at building one to live in. (what? Never have to ever sell my home, just take it with me? Yes please!)

So I joined the Tiny House People group on Facebook, when it was still under a thousand members, and asked a lot of questions, pretty much all about moving the houses, where people went with theirs, and more questions about these homes on wheels. I was met with more answers telling me the homes weren’t really great for towing around, but more for just staying put, but that you could move them if you wanted to, just that most people don’t.

So what was the deal then with the wheels? And didn’t I see a tiny house by Outdoor Research that had almost 10k miles on it? (I did, it was built by Zack Giffin of Tiny House Nation fame and featured in the film Livin’ Tiny: Quest for Powder.) Oh but even they blew out their truck towing it and needed a new one? Okay, so what kind of truck can tow a tiny, and are they really only for staying put?

Enter Tiny House Giant Journey who at the time of my writing this, have traveled more than 22, 000 miles with their tiny house on their tour of 27 states and provinces around North America, and I say hey, those wheels are there and you can USE them!

Tiny House Giant Journey travels through the Petrified Forest park in Arizona while an RV drives by. Licensed under CC BY-SA 4.0 via Commons -
Tiny House Giant Journey travels through the Petrified Forest park in Arizona while an RV drives by. Licensed under CC BY-SA 4.0 via Commons – 

So wait, that’s a pretty big truck they have there, how much do these homes weigh anyway? Well, the one in the pic above weighs over 10 thousand pounds. That’s a ton of weight! Okay, actually, that’s 5 tonnes of weight!  So I’m gonna need a pretty big truck, right? They’re using a Ford F250 with a towing capacity around 12000 pounds.  I hope that 10k+ weight they list is loaded, and not empty!

Okay, so you’re looking at a really big truck, and a fairly small tiny house (that one is only 20 feet long, and there’s plenty of people wanting to build larger) and being really really careful with watching what you build out of! And that truck’s going to get you around 8-10 mpg even in a diesel that’s gonna cost if you’re pulling a big house behind you wherever you go!

Hmmm, okay, then I better budget in a truck to pull it, but also probably not pull it all that often, why did I want wheels again? Before I get off on a tangent about the wheels, and costing out everything, I did take some time to learn things about trucks, and towing that would probably be great to share with you here.

First of all, you need to have an idea of what these homes weigh.  People throw out estimates in the Tiny House People group all the time. I see people suggesting guesstimates of 500lbs per linear foot, (which is in keeping with the weights of Jenna and Guillaume’s home).  I see people weigh individual components and then track the weight on a spreadsheet, and I see them go to weigh stations and get an actual weight!  I highly recommend the latter, but the former must be used during the planning stages, in order to know if you’ve planned to tow an elephant behind you or not. So that I don’t duplicate what I think is a handy resource, know that you can google weights of building materials and appliances online, but Macy Miller has a handy resource on her Planning Tiny site that will help you know some approximate build weights on materials. You can download it from here.

Okay, so you can reasonably assume that your 20 foot home will be around 10,000 pounds. (I’m going with this figure for ease of illustration, though I know this will vary greatly for many reasons) That means you need to either build it a lot lighter so that you can pull it with a lighter truck, and pay a lot of attention to using really light weight materials, like using metal framing, less cupboards, lighter plumbing, etc, and also not filling the home with a lot of really heavy things. (it all adds up!)

So then you need a truck that can pull 10,000 pounds, and a Ford F250 has a towing capacity of 12,000 pounds, sounds pretty simple! Can a smaller truck pull that much? I see some vehicles with a GVWR of 10,000 pounds, if I’m really great at building lighter, can I use that to pull?

Well, first of all, GVWR and towing capacity are not the same thing. GVWR, stands for Gross Vehicle Weight Rating, and it includes the weight of the tow vehicle, and everything in it, and the tongue weight of the trailer. A 7000lb truck, with a 10,000lb GVWR can safely hold another 3000lbs including passengers, stuff in the bed of the truck, and the tongue weight of the towing vehicle.

Okay, so the truck with a towing capacity of 12,000 lbs, it has a GVWR of 10,000 lbs, so I can then fill the bed of the truck and the truck itself to a total adding up to 10,000lbs plus pull an extra 12,000lbs? Sounds easy peasy to me… but wait, no? That’s not how it works? Oh, there’s a thing called GCWR, or Gross Combined Weight Rating, and that takes into account the weight of the tow vehicle, the payload in the tow vehicle, the tongue weight, and the trailer weight and all of the payload in the trailer too. That’s the number I need to pay the most attention to.

So I’d need a truck with a GCWR of more than 10,000lbs.  How is the GCWR calculated? It’s based not only on the towing capacity, and the GVWR, but also the axle rating, the frame and spring ratings, in combo with the engine rating, the brakes, the tow assembly, cooling… oh my this is getting complicated, it’s not something a layperson can calculate on a home built tiny. To guesstimate from a regular trailer, you can add the GVWR of the trailer and the tow vehicle together and come up with a number, but it can still overpower your vehicle.  Best to get the numbers from the manufacturers, but here’s a great source if you want to learn about the numbers, and their pages on the different vehicles linked in the tab at the top of the page, are fantastic to compare the different manufacturers and models.

Looking at that site, links me through to look at that Ford F250 again, and it shows me that with a towing capacity of 12,000lbs, it has a GCWR of 19,000-22,000lbs depending on the axle ratio. (the diesel has even more). So that truck, or a similar model, weighing about 7,000lbs (what google tells me) loaded with maybe a thousand pounds, and can pull around 12,000. Math is adding up, right?

So is it really that simple? After all that confusion? Well, you also need to know what tongue weight you need, and what axles you need on the trailer itself. A 10,000lb trailer requires a tongue weight between 1000-1500lbs. How did I figure that? (tongue weights should be between 10-15% of the total trailer weight according to and but between 7-8% and not exceeding 10% on I’d use my judgement and determine that a too low tongue weight can make the trailer sway, and a too high one can interfere with the tow vehicle’s steering, but a just right one, will keep both the vehicle, and the trailer level when hitched. Also helps that more sites agreed with the 10-15% guidelines.

You can take the trailer to have the tongue weight calculated just like you do to weigh the entire thing. You can even purchase a weigh safe ball mount that tells you before you ever drive away. The guide I linked above has other methods of determining tongue weight listed too, it’s a great guide! If it’s too heavy or too light, then your load isn’t balanced. So how exactly do you balance the load?
Here’s where it gets a little tricky, because balancing a load is as simple as balancing two kids on a teeter-totter. Except that you can just move the kids a lot easier than you can move your kitchen. The axle of the trailer acts as a fulcrum on a lever, so if one side is too heavy, move items closer to the axle, or add heavier items on the other side of the axle.  So where you put things in the tiny house, may very well be determined by their weight. I found an absolutely amazing spreadsheet and informational page about trailer balancing, that will help you figure out exactly how to do this safely on your own trailer, (and I intend to use this in my own build). I’d also recommend paying attention to balancing side to side as well.

Other than that, it’s just a matter of what weight rating axle you need on your trailer (or if more axles are better), and if you’re going custom and have already decided where everything goes, you can determine where to place that axle in order to balance the trailer! You can get information on weight ratios based on axle size from this page. I know most people get the trailer then design the house, but I wonder just how many tiny houses are actually balanced.

As to single or tandem axle trailers, there are advantages and disadvantages to both. Single axles are lighter, and more maneuverable, but tandem axles are more stable and safer. Single axles don’t require brakes, but having brakes makes any trailer safer. Tandem axles are heavier and more expensive, and require twice the maintenance (4 wheels instead of 2) but single axles cause more wear per tire. Single axles are great if you have a very light trailer and need to be able to maneuver it into a tight space, but for a 10,000lb tiny house, I’d play it safe and go with two.

Now you know how to determine the weight of the house, what size towing vehicle you need, how to balance it and determine tongue weight, how many axles you need, what next?

Make towing it safe.  Follow the state guidelines on adding running lights, brakes and consider additional safety measures to make sway less of an issue. Use safety glass in the windows, and protect any that are facing the wind during travel. Secure anything loose in the trailer while in tow, and never tow with living creatures inside. (that’s illegal in any case, apart from livestock trailers) Make sure the trailer is hitched up to the towing vehicle with a hitch that’s rated to pull that much weight (generally okay when purchasing vehicles with towing packages, but be certain) Use sway bars, chains, trailer signals, consider anti-sway control and other safety measures like wider side view mirrors (some states require these). Plan your route and know if your trailer can safely navigate without getting caught under a bridge, too heavy to cross one, clearances on rutted roads. Check your tire pressure, on both the trailer and the tow vehicle, at the beginning of every trip, and every few hundred miles through the trip. (if tires need their wheel bearings replaced, get that done too)

Okay, I think I have it figured out now, and while the weights don’t seem all that complicated anymore, there is a lot of calculations to make. On top of that, I need to look at the cost of the vehicle, and insurance on both it and the trailer, what fuel will cost, maintenance, and then even what it would cost to park it various places as I travel.

Would building on a foundation be a smarter move? Would traveling and staying in hotel rooms be less expensive or easier? Is an RV a better choice if I am constantly moving? Would parking the tiny and just traveling light work better? I can see why people say that most tinys stay put. I’ll go further into some of this in another post, leaving this one strictly on topic.


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