Weight vs frontal area

boogie_4wheel wrote:
The weight of the trailer has the largest impact of getting moving form a stop (or coming to a stop).
The frontal area or drag of the trailer has more of an impact while you are traveling at speed.

This is correct. In addition to our travel trailer, we also have owned an enclosed car trailer for 18 years. I've found that there's little difference in mileage if the trailer is loaded or empty.

Years ago I worked for a company that built enviromental clean up systems in corgo trailers. They were almost always 6' ceiling height 24' long. I found that towing the trailers empty or full of equipment made almost no differance. One time we got an order for a unit that needed 8' ceiling height. We had the trailer company build it. When I picked it up empty you would think it 20,000 pounds in it . The 2 foot height differnce made a huge differance.

FWIW, my BIL (the cheapskate one) is moaning big time that his new Ecoboost doesn't get 20 MPG while towing, more like !0-12 depending on what's back there.
Of course, the guy has a nice Class A and a brand new garage to house it, also, but I haven't seen it move in four years. I'm sure it kills him when he gets to the pump with that.

boogie_4wheel wrote:
The weight of the trailer has the largest impact of getting moving form a stop (or coming to a stop).
The frontal area or drag of the trailer has more of an impact while you are traveling at speed.

I notice a big difference between pulling my toyhauler, and pulling a flatbed trailer with a tractor loaded on it. Getting rolling feels the same, but maintaining speed is easier; the truck doesn't work as hard.

x2 on weight vs. frontal area. From physics, once you are moving at a constant speed on level ground weight has very minimal effect on your mpg. Only to the extent that it effects frictional losses in tires, bearings etc. to a minor degree.

Frontal area affects wind resistance which is a square law function and has a constant effect on drag.

For comparison, I have a 7x14 ft cargo trailer about 5,000lbs full and a 35' outback 295RE, 9,000lbs full and a much larger frontal area. I tow both across the cascades to eastern oregon. The mileage difference between the two is 1.0-1.5 mpg better for the cargo trailer wth smaller frontal area (11ish vs. 12.5 ish). And that's going over some low elevation passes. Going up and down the columbia gorge where is it reasonably flat, the difference is under 1mpg.

In both cases I drop 8-10 mpg or so compared to unloaded the same speed. Wind resistance and frontal area kills mpg.

10mpg is about normal, unless you have a diesel.
many people don't realize how much the frontal area has on gas mileage.
they worry more about carrying 100lbs. of water, since they focus on the weight, when it really won't factor in gas mileage as much as the barn door they're towing thru the air.

and pulling a 5000lbs. TT with a v-6, is just asking for trouble. unless it's an Ecoboost v-6.
i tow a 5000lbs. loaded HTT with a v-8 and there's no way i'd tow it with a v-6.

Ron P68 wrote:


...would a single axel trailer, 1000 lbs. lighter get better mileage than the heavier model...?

NO

Actually, 10 mpg sounds about right. Figure anywhere in the 6 to 10 mpg area. Also, don't expect to race up hills. In my Class C, keeping 50mph going up a significant hill is not possible. At 70 mph, I get 6 mpg. At 60 mph I get 8 mpg. That is a 33% increase in gas mileage for a 15% decrease in speed.

The weight of the trailer has the largest impact of getting moving form a stop (or coming to a stop).
The frontal area or drag of the trailer has more of an impact while you are traveling at speed.

I notice a big difference between pulling my toyhauler, and pulling a flatbed trailer with a tractor loaded on it. Getting rolling feels the same, but maintaining speed is easier; the truck doesn't work as hard.

X2 forget about mileage and enjoy the journey.

I've seen RVers spend thousands of dollars trying to improve mileage only to increase by 1 to 2 MPG. A couple have even ended up with worse mileage.

I gave up worrying about mileage two trucks ago. Now I buy for safety and comfort.

Welcome to the Forum...
Mileage has 4 factors:
frontal area
weight
towing conditions - hills/mountains, wind, etc.
speed. (slow down)

My advice from experience...forget about mileage and RV'ing. If you are going to tow, you are going to use lots of fuel. When we decided to stop worrying about mileage we were more relaxed and started having more fun..