How-To determine trailer weight for your Tiny House

by Kent Griswold on June 9th, 2011. 12 Comments
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Perhaps there is no Tiny House subject (or trailer subject, in general) that causes more arguments and confusion than that of weight. Between the cryptic way that RV weights are reported by the manufacturers, the lack of clear standards by the DOT and the often deliberate misinformation spread by dealers; trailer weights are confusing at best. Because of our recent trailer purchase I have been motivated to try and really understand this often mystifying issue. The following is what I learned, and in my humble opinion, an authoritative explanation of what the truth really is.

Now, our trailer got its beginning as an RV, of sorts. So much of my research has a travel trailer/RV bend to it. If you purchase a trailer from a specific trailer/hauler dealer they should be able to give you specific weights for the axels, trailer, tongue, and hitch. If not, immediately turn around and go see someone else. For our purposes though, I am going to walk you through our process (and one that is becoming more popular with each small home.)

Let’s start with the 2 stickers that are required by law on every RV sold in America. The RV manufacturer is required to include a Weight Sticker on the RV that details all the important weight ratings and maximums. This sticker is usually located on the inside of one of the kitchen cabinet doors. If your trailer has no camper portion (let alone cabinets or cabinet doors) you can simply forego this step and hope the other steps lead you to the same result.

The other sticker required by law is a tire capacities sticker. This is usually outside the RV, somewhere near the hitch (as ours was) on towables. It can also be on the inside door frame, near the engine compartment or on the inside of the service door for motor coaches. In addition to these 2 stickers on the RV, you’ll also need the ratings from your tow vehicle if working with a towable. Now here is where it gets rather tricky. The acronyms.

The RV’s weight sticker displays all of the most important weights as they apply for your RV. The information on this sticker has changes over the years, but it should contain at least some combination of the following:

  • GAWR (Gross Axle Weight Rating). The maximum gross weight that the axles will carry. This is independent of the weight rating of the tires.
  • GVWR (Gross Vehicle Weight Rating). The maximum weight that the axles and/or the tires will carry. It is the lesser of the axle carrying capacity or the tire carrying capacity
  • UVW (Unloaded Vehicle Weight). The total weight of an RV as it was delivered to the dealer. It does not include any dealer installed accessories.
  • NCC (Net Carrying Capacity). This is the actual amount of cargo allowed. It is in simplest terms, GVWR – UVW = NCC. This is sometimes listed as CCC (Cargo Carrying Capacity).
  • GCWR (Gross Combined Weight Rating). This is the maximum weight of this RV plus any towed vehicle combined. This is listed on the RV for motor coaches, but not towables. For towables you can get this rating from the sticker on your tow vehicle.
  • Hitch Weight. The maximum weight the hitch can support. In the case of a towable this is the maximum weight the RV’s hitch can support and has nothing to do with the hitch rating of the tow vehicle. In the case of a motor coach this is the hitch rating of the hitch used for towing a chase vehicle.
  • GVW (Gross Vehicle Weight). See GVWR
  • CCC (Cargo Carrying Capacity). See NCC
  • Gross Dry Weight. See UVW
  • Dry Axle Weight. The weight of the trailer when the RV is on the hitch. This can be calculated as UVW – Hitch Weight = Dry Axle Weight.

All of these may not be on your sticker since some only apply to certain RV classifications. In addition, there may be other weights listed. In addition to the RV’s sticker, you’ll need to understand the weight rating of your tires. For towables you’ll also need to get the ratings from your tow vehicle. This sticker is usually found on the door frame of the driver door, or can be located in your owner’s manual. It contains many of the same ratings as they apply to the tow vehicle only.

By this point I was already beginning to feel the effects of information overload. Did I really need to fully understand all of these numbers as well as the mathematics involved? Was it possible to reduce this down to a manageable level and make intelligent, informed decisions? I finally worked it out to a few basic formulas that allowed me to fully comprehend all the important information.

Let’s start with the gross weights since these are ratings that are difficult to modify. It’s easy to adjust the amount of cargo you’re carrying or the weight of your Tiny House building materials. The gross weights are fixed however, and short of making major modifications to your design, are absolute barriers.

The most important weights to anyone considering a Tiny House are:

  • GVWR of the trailer, the
  • GAWR of the trailer, the
  • Hitch Weight of the trailer, the
  • Hitch Rating of the tow vehicle, the
  • Load Ratings of all our tires and the
  • GCWR of the entire rig as noted on our tow vehicle’s sticker.

These are the ratings that cannot be negated or exceeded regardless of the finished build or the contents of your house. There are very good engineering and legal reasons for not exceeding these ratings, no matter how you slice them.

If you pay the most attention to your gross weight ratings, the rest of the capacities seem to take care of themselves. Not that the others aren’t important, it just seems easier to deal with the gross ratings and let the other level out as needed.

Stay tuned for more weights such as vehicle weight, tongue weight, hitch weight, etc. For now though, my brain is fried. In the meantime, if you enjoyed this post or found it helpful consider sharing it on Facebook or Tweeting the link!

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Bigger does not always mean better. Progress does not always mean forgetting our roots in order to forge a new future. Blogger, photojournalist, and hobby farmer Andrew Odom has spent much of the last few years rediscovering the lost art of living, growing, and being truly happy. Visit him online, find him on Facebook, or follow him on Twitter.

12 Responses to “How-To determine trailer weight for your Tiny House”

  1. Rich says:

    I find this to be very informative. I am in the process of taking the steps necessary to build a tiny house on wheels, however there is one area in my research that I cannot find answers. How much does a typical tiny house weigh? The articles and pictures are detailed enough to give general guidelines on the construction and materials, but how do you determine whether the vehicle’s towing capacity does not exceed the finished house, or how do you know if you are building a house on a trailer that when finished weighs too much? It would seem like a good ideal in the articles to ask the builders what the finished product weighs? This would at least give a `general’ idea of finished weight in relation to the size of the trailer and construction materials used. If the finished weight was a couple thousand pounds under Gross wts., great! If a finished product was just 100 lbs. under, then some serious modifications would have to be done. Again, it would be helpful as `general guidelines, as each would defintely be different.

    • Pepper says:

      We’re putting the finishing touches on our tiny house, a slightly modified version of Jay Shafer’s Lusby plan. It’s on a 7 x 18 utility trailer with a 10k lb GWVR, and the official weigh station scale puts it at 6,480 lbs – without personal belongings, the refrigerator or stove. The trailer itself weighs 1,250 lbs.

      • Carolyn MVaussies says:

        Thanks, that good to know, as his plans tend to “over” build some, framing wise. There are areas that could be lighten up some.

        I’m tearing down an newer RV Trailer myself for the trailer(had a bad roof leak) & it’s expensive “guts”(Jacks, frig, stove, water tanks, toilet, gas & electrical set ups, etc.) Very surprised how scary wimpy they are built. The RV Trailer is rated at GVWR 10,100 lbs.

  2. Hey there Rich. If you take a look at the Tumbleweed site you will see that each model lists the dry weight of the house including the trailer. For instance, the Weebee comes in at 4900 lbs. with trailer: http://www.tumbleweedhouses.com/houses/weebee/?amp=&ev=7a60d71fa5

    Right now our home does not have a final weight because it is not finished. We are writing and living as we build and go. The best way I have found is to be very specific in your building materials (quantity, size, weight, etc). For instance, we will be installing roughly 402 lbs. of windows. Our subfloor will weight right at 970 lbs. Yes, it is tedious, but it is the best way we have found to do it.

    I write about constructing a tiny house on this blog once every two weeks. However, you can find us on a more regular basis at http://www.tinyrevolution.us or on facebook at http://www.facebook.com/tinyrev

    Those two sites will give much more of the day-to-day procedures and adventures of building a tiny house….or at least building ours! Thank you for reading and commenting, my friend.

  3. Rich says:

    Correction.

    `how do you determine whether the vehicle’s towing caacity does not exceed the finished house?’

    Shoud have been.

    How do you determine the total weight of the finished house so it does not exceed the weight capacity of the trailer? (finding out halfway through construction the house weight exceeds the trailer capacity would be disastrous)

    The other thing I need to figure out is what type of vehicle would be best to own to tow tiny houses safely?

    That is the reason for my suggestions in disclosing the weight from readers houses that are posted.

  4. I agree with you Rich. It would be disastrous. In our case, we thought about the size of our desired tiny house. We then thought about materials we KNEW we wanted to use (metal roofing, on-board hot water heater, full size fridge, etc) and did a very rough calculation. We then began looking for a trailer that had augmented axle weights as well as multiple axles. We felt strongly that this would insure us of meeting weight requirements.

    We will be towing our tiny house to our land in NC via a Chevy 1/2 ton HD truck. It is a king cab (which doesn’t really matter) but does have a towing package.

    I try and think of an RV equivalent to your tiny house. Let’s say you are building a stick frame tiny house 14′ feet long. Google an RV trailer of similar size. Remember, it is some stick framing but a lot of aluminum and fiberglass. So multiply the weight x2. Then consider your automobile and its towing capacity. If those two number seem compliant, I think you are good.

    • Carolyn MVaussies says:

      On the tow vehicle. What it is DOES matter. A 1/2 ton is a bit on the wimpy side, but can be done with planning. I have towed horses with different trailers & trucks/vans for over 35 yrs. MA to FL many times. Having a Kingcab is good as it should have a longer wheel base. It stabilizes the rig better………”The tail doesn’t wag the dog”.
      I have towed with a 1/2 ton, I beefed up the rear springs with added leaf springs, Trany cooler, stayed away from High winds(pull over & sit it out!) hills(or forget pride & put on flashers & go 40/45), TAKE your TIME on a Highway Merging space.

      • I’ll second that. I’ve pulled with a 1/2 ton truck before, and I wouldnt want to go very far with it. Tiny houses are big and often heavy.

        I think a couple good general guidelines might be:
        Always get your trailer brakes set up and working. They make a big difference in controllability of the load. If you do not have brakes, you aren’t exactly legal… if you are doing a local move, keep your speed down, say under 35mph. It is hard to stop a big load with just the truck’s brakes.
        If the trailer weighs more than the truck, use a 3/4 ton truck or bigger. Smaller trucks do not have the suspension and/or brakes to stay in control of a large load.
        Be sure you have adequate safety chains for your tiny house: 5/16 to 3/8″ ‘proof coil’ steel chains should be in the range you’d need.

        Journey well!

  5. [...] subject (or trailer subject, in general) that causes more arguments and confusion than that of Weight. Between the cryptic way that RV Weights are reported by the manufacturers, [...]

  6. et says:

    But don’t forget to add things like appliances, furniture & personal stuff if you are ever considering moving the house with these inside.

  7. There are other things as well: frontal area can be huge for these houses… You usually have to go slow and fuel economy is going to be pretty low.

    If anyone in Western WA has need, Zyl Vardos can haul for a reasonable fee.

    Let me know if you have any questions. Happy trails, no?

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