How Much Trailer Can You Tow (Part 3)?

2013-12-16 Clip Art Weight LifterIn Part 1, I discussed some general thoughts on matching a tow vehicle and a trailer, to include tongue weight and gross weight specifications.

In Part 2, I took a deeper dive into tongue weights and presented the idea that a tow vehicle’s maximum tongue weight specification is usually the limiting factor in how large a trailer you can tow.

The conclusion in both is that perhaps we bought a trailer that is too heavy for our Ford Expedition; although I shared that I understood all the weight implications before we purchased.

So here is the rest of the story, as Paul Harvey used to say.

2013-12-16 Clip Art - Truck and TrailerWe looked at a lot of floor plans and Joyce liked the Milan 26RLS best. I liked it too. What was surprising is that several manufacturers offer a 26RLS model and the floor plans are similar – almost identical.

Joyce liked the trim of the Milan better, along with a shower enclosure, which several makers had a itsy bitsy bathtub instead. I agreed with Joyce.

But floor plan and trim were not the most important thing to me… remember I like to backpack, so any trailer is a luxury. Since we mostly boondock (not camping in a campground) for extended periods of time, fresh water capacity was high on my list.

2013-12-16 Clip Art - WaterAlong with the ability to haul a lot of water, it was my responsibility to match the trailer to our tow vehicle. This is difficult because you generally have to work with trailer brochures until you find the exact trailer that seems to fit your requirements. At that point you can get the actual empty weight of the trailer on a sticker that is affixed to the unit, but tongue weight isn’t included. And more than likely, the dealership doesn’t have a tongue scale.

The next problem is trying to determine how the weight will be distributed once you put all your stuff inside it and fill up the water tanks, propane tanks, and add a battery or two. Usually you have to actually buy the trailer to get a final weight.

When shopping, we looked at the specifications of every trailer we were interested it, knowing that the final weight from the factory would probably be 8%-12% higher once the options are added. Below is a table of weights from several 26RLS models of different brands.

Comparisons of Trailers

 The first row of data is for our Milan trailer. Definitions for each column are:

GVWR: the maximum the trailer can weigh after you add all your stuff, water, propane, etc.

Hitch Weight: is the tongue weight for an empty trailer based on the dry weight from the factory. The dry weight does not include any options and is always lower than what is delivered to your.

Dry Weight: is the manufacturer’s specification for an empty basic trailer. Plan on adding 8%-12% to the actual trailer.

Fresh Water: is the capacity of the tank.

Grey Water: is the capacity of the grey water tank (kitchen and bathroom sinks, and shower drain waste water. They are usually empty when you leave home and many campers stop at a sanitary dump station to off-load the grey water.

Black Water: the tank for your toilet. Same goes with these for off loading.

Payload: also known as cargo carrying capacity. This is the stuff you add to your camper. This is calculated by subtracting the Dry Weight from the GVWR. It is also overstated, because the actual weight of your trailer will be higher than the factory specification.

Notice that the Milan has the highest hitch weight and the highest ratio of hitch weight to GVWR. It also has the highest payload rating. And it has the largest fresh water capacity at 100 gallons, which is about 835 LBS full.

BALANCING THE CARGO

teeter totterMost trailer manufacturers and industry experts say about 60% of the cargo weight (including water, propane, battery, etc.) should be in front of the axle. This wouldn’t work for us if we were to purchase the Milan, as it would raise the tongue weight to 1400 LBS, well above our Expedition’s max weight specification of 920 LBS.

Our Milan is made by Eclipse Recreational Vehicles, Inc., who until recently only made Toy Hauler Trailers of which their Attitude models are the best known.

Toy Haulers are travel trailers with a rear section designed to transport off road vehicles and fuel. They carry a lot of weight in the rear and must be designed to balance this load with the rest of the trailer. Because of this weight requirement, they are “hitch heavy” from the factory and have a frame designed to handle this load, and to handle the additional stress of off–road travel. This philosophy has carried over to several of their Milan travel trailers. So I wasn’t surprised by the weight specifications. To balance the load properly, I figured the fresh water tanks were probably to the rear of the axles, similar to the weight distribution for hauling off-road vehicles. I was correct.

water tanks

Diagram of frame, axles and tanks (not to scale)

So with full water tanks it appeared I would be able to load the trailer and keep the tongue load below specifications, as long as all the other stuff was properly located. Balancing a trailer is like a teeter-totter. By moving the heavier person forward or backwards on the teeter-totter, you can raise the other person in the air, balance both, or even raise the heavier person in the air. This is easy to calculate using the lever/fulcrum calculations.

balance beam

The force at each end of the beam is calculated by multiplying the weight at the end by the distance to the center (fulcrum). Using the formula, one can calculate the needed weights to balance the beam, or even apply a specific weight at one end, which in our dilemma would be the trailer tongue.

Of course it is not that easy with a trailer, especially one with dual axles as we have. Weight is not concentrated at each end, and the structure of the walls, roof, and built-in components cannot be moved around.

Trailer fulcrum

So we added our batteries, propane, water, solar system, equipment, clothes, food and a bunch of other stuff we needed and then weighed the trailer. Total gross trailer weight was 8,460 pounds, versus an empty weight of 6560 LBS from the factory.

We had to move things around a little and move the spare tire, which was mounted under the trailer at the front to the rear bumper. Once done; we were within specs for everything. It wasn’t that difficult, because Eclipse had done a good job engineering the frame and construction.

MEASURING TONGUE WEIGHT

There are many ways to determine your tongue weight, such as going to a truck stop and placing only the trailer tongue jack on the scale, building a scale using a household scale (Google is your friend if you want to learn more), or you can buy a Sherline Tongue Scale.

Sherline Tongue Scale
Sherline Scale and Ball Socket Adapter.

This scale can be placed under the trailer tongue jack, which isn’t exactly accurate (probably reads 5%-8% heavy), or using the included adapter it can be placed in the trailer’s hitch ball socket.

I found it much easier to place the scale under the ball socket using the included adapter, which is the most accurate method.

Scale with adapter.
Scale with adapter.

Level the trailer with the tongue jack, and then using a floor jack, simply lift the tongue off the jack a fraction of an inch.

Trailer Lifted off the Tongue Jack.
Trailer Lifted off the Tongue Jack.

Once the tongue is lifted, it is easy to read the actual tongue weight (see below).

Scale Face using Floor Jack

Our tongue weight was 900 lbs, just under the maximum of 920 lbs. With a total trailer weight of 8,460 lbs, we had a tongue weight of 10.6%. Everything was in specs, but the tongue weight was a too close for comfort for me. In addition, we were getting some trailer sway when semi-trucks passed us at high speeds.

So I rearranged our cargo and purchased a ProPride 3P Hitch. The ProPride is much heavier than our Equal-i-zer Weight Distribution Hitch, so after installing the ProPride and loading up the trailer with everything for a long trip I weighed the tongue.

Raising the Tongue with the ProPride installed.
Raising the Tongue with the ProPride installed.

ProPride Tongue Weight
As I had planned (an hoped), the tongue weight is now just under 850 lbs.

So it was time to drive to the truck stop and weigh everything – full tank of gas, full fresh water tank, full propane tanks, food, wife, dog, all gear and equipment loaded in the tow vehicle and trailer.

2013-16-2013 Cat Scale Weights

UPDATE (Jan 16 2017): In the text above I added the weight of the ProPride Hitch to the tongue weight. I have changed how I weigh tongue weight using the ProPride Hitch. Also, for a complete discussion on how tongue weight should be calculated see this post on Weight Distributing Hitches and Tongue Weight.

TRAILER SWAY

One last subject I should discuss is trailer sway. Because a trailer is connected to a pivot point behind the tow vehicle, it is subject to the force of the wind or even passing semi-trucks. These forces push or pull the trailer from side to side, requiring the driver to constantly adjust to keep the trailer straight. Too light or too heavy a tongue weight can exaggerate the problem.

Sway pivot point

Sway wind

Sway semi-truck

To overcome sway, some owners use a sway control hitch, and most use a combination weight distribution sway control hitch. The Equal-i-zer brand WD hitch shown in Part 2 of this series is also a sway control hitch. The load bars apply friction to the trailer to reduce sway (see below).

Equal-i-zer WD and Sway Control Hitch.
Equal-i-zer WD and Sway Control Hitch.

We used an Equal-i-zer with great results on our 2006 Fleetwood Niagara Folding Tent Trailer. But the Milan is much longer, taller, and heavier. We were getting some sway in wind, and when a semi passed us at high speed. Nothing severe, but enough to require a steering correction. This concerned me because in an emergency situation the results could be tragic. So we upgraded to a high end hitch made by ProPride.

What is important about this upgrade is that the ProPride is not a sway control hitch; but a sway elimination hitch – it eliminates sway, it does not try to control sway – which is a big difference. Instead of trying to explain how it works, I’ll just quote ProPride…

The ProPride 3P main unit consists of two 3/4″ thick links that project the pivot point of the trailer forward to near the rear axle of your tow vehicle. By not allowing the trailer to pivot side-to-side on the ball trailer sway is eliminated.

ProPride Pin Point Projection Hitch on our rig.
ProPride Pin Point Projection Hitch on our rig.

One additional advantage about the ProPride, which I didn’t realize until I installed it, is that the rear lift gate can be opened while hitched to the trailer. This is something we had been unable to do in the past with any of our SUV’s. It sure is nice!

ProPride-1-3 ProPride-1-2

If you want to know more, then hop over to the Airstream Trailer Forum thread titled,
The unofficial pp users guide… Lots of great information there and it should keep you busy for several hours.

All I can say is that the ProPride works as advertised, and the customer service is legendary.

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