W&M 3, How much can I tow?

I see this question often, and my standard reply is always, “Check your owners manual!”. While that’s the best place to start, let’s take a little trip deeper down that rabbit hole.

In “Weights and Measures 1: What’s it all mean?” we talked about all the different terms and basics we need. (If you skipped that, you may want to revisit it before falling down this rabbit hole).

So let’s say I have a nice pickup truck as my towing rig, and it’ll tow 15,000 lbs in a bumper pull configuration, or 18,000 lbs in a fifth-wheel or gooseneck configuration (more about towing types).
Great, so now I know my maximum towing weights? We can go now, right? Well, hold on a second, let’s talk about what we’re towing!
Let’s say i’ve got a 32′ Travel Trailer with a GVWR of 11,000 lbs, and it’s a bumper pull (I really do!). Ok, what else do I need to know?!?!

Well, in bumper pull configuration, my truck will tow (note the difference between towing and pulling!) 15,000 lbs, so that part’s all good!

The next part I want to look at is the tongue weight. Tongue weight is most crucial in the “Control” category of towing. If you have too much tongue weight, you’ll have a saggy rear end on your tow vehicle, and you’ll have less steering control up front. Too little tongue weight, and you’ll suffer from ‘fishtailing’ of the trailer, as well as potential slipping of the drive wheels on the a RWD vehicle.
Check out this link for lots more info on tongue weight.

I always tell people to never exceed the manufacturers tow rating because the people that designed it know the people who built it, the people that wrote the book about it, and the people that did the math to know when it’ll break. Don’t break your rig.

Once you’re all loaded and set, go get yourself a Non-Commercial Weigh so you know what you tow before you go! 🙂

W&M 2: Motorhome Math

If you’re in a motorhome, and not towing, then you’ve got very little to worry about. Let’s say you have a class A diesel pusher with a GVWR of 40,000 lbs, and it’s dry weight is 35,000 lbs. That means you have 5,000 lbs of weight capacity that you can add to this motorhome in fuel, water, stuff, people, pets, goodies, gizmos, gadgets… you know, ‘stuff’. 🙂 Seems like way more than enough, right?!

So let’s do some math:
If we fill up our 100 gallon fuel tank with diesel at 7 lbs/gallon (link), that’s 700 lbs.
Now we fill up our 100 gallon freshwater tank, at 8.5 lbs/gallon, that’s 850 lbs.
We also need to fill our propane tank, which is 40 gallons, and at 4.2 lbs/gallon that’s 168 lbs.
Now we bring aboard our camp chairs and table, our clothes, our food, our canopy, and all the other stuff we want to take with us to make life on the road more comfortable, so let’s say all of that is 2,000 lbs. I know, seems like a lot, but if you start weighing stuff, especially tools and spare parts, you’ll find it all adds up very quickly!
So, let’s add up all that stuff:
Fuel: 700 lbs
Fresh Water: 850 lbs
Propane: 168 lbs
Stuff: 2,000 lbs
Now we’re up to 3,718 lbs of stuff! We’re left with 1,282 lbs of ‘weight space’ left over, which means we can add more stuff! WooHoo! Time to break out the Ham radio gear! 😉

You don’t have to weigh every single item on board, but here’s what I suggest:
Fill up your rig with everything you want and need, then go get a Non Commercial weigh.
Once you know what your rig weighs fully loaded, you can see for yourself how much room you have, or how much you need to take off.

Non-Commercial weigh

Anytime you want to know the total weight of your rig, all you need to do is go to your local truck stop!
Park somewhere (in a designated space!), walk inside, and ask someone at the fuel desk for a “non-commercial” weigh ticket. This let them know that you’re not a Commercial driver, and they’ll log it differently in their system. Commercial drivers have to provide Truck, Trailer, and load numbers, along with Company name and other stuff, which you won’t have since you’re personal use.
After they give you the okay, go back to your rig, and drive slowly onto the scale, lining up in the center (left to right), and making sure your axle sets are in different sections of the scale. If you stop with the speaker/microphone box just outside your drivers window, you should be fine, and you can ask for a little help over the speaker/mic to get adjusted correctly.

Once you’ve settled down, they’ll let you know they’ve got your weight, so clear the scale (ALWAYS DRIVE SLOWLY on the scale!), park, and go get your ticket inside!

W&M 1: What’s it all mean?

When we’re talking about a house on wheels, it’s important to understand all the different terms used to talk about weight; what they mean, how to use them, and why they matter.

First things first, here’s some terms you need to know:

1) GVWR: Gross Vehicle Weight Rating
This is the total amount of weight your vehicle is designed to carry, and going over this amount is a recipe for disaster.
This applies to any single vehicle, so you’ll have one for your truck (or tow vehicle), another for your trailer, or one for your motorhome.
2) GCWR: Gross Combined Weight Rating
This is the total amount of weight your vehicle can weigh in combination with another vehicle, such as when you’re towing a trailer. If you’re towing a trailer, then you’d want to make sure your GVWR of your truck, plus the GVWR of your trailer, is NOT more than the GCWR for your tow vehicle.
3) GAWR: Gross Axle Weight Rating
This is the total amount of weight a single axle can support. Not as common, but worth noting here.
4) Towing Capacity
This is the maximum towing capacity for your vehicle, or the maximum amount of weight it can tow.
5) Curb (dry) weight
Curb weight is how much your vehicle weighs dry and empty (sitting on the curb). Think of this as how much your vehicle weighs without stuff, people, fuel, water, luggage, so on and on and on…
6) Tongue Weight
On your tow vehicle, this is how much weight you can put on the tongue of the vehicle, which is different than the total weight of the trailer.
On your trailer, this is how much weight should be on the tongue of the trailer, which is different than the weight placed on the wheels.

Okay, now that we have some terms down, let’s add one more section, weights per gallon:
1) Water weighs 8.3 lbs per gallon at 62°F, and
2) Gasoline weighs 6.3 lbs per gallon, and,
3) Propane weighs 4.2 lbs per gallon, and,
4) These weights vary with temperature because the mass changes with density.

The reason these numbers matter is because vehicles (all vehicles) are designed with specifications, and so long as they are used inside those specifications, they will operate as intended, as tested, and as certified. Anytime you operate a vehicle outside of its specifications, you run the risk of causing damage to the vehicle, losing control of the vehicle, or other troubles.

Read on in the following posts to learn more about Weights and Measures.