Any way to calculate difference in gas mileage based on difference in weight?

[Tevans1224]

Hello. I’m new to the forum and apologize if this has been answered but I couldn’t find anything. We are looking at two trailers and the biggest difference is weight. I’ll be towing with a 2017 Ford F-150, 4x4, 5 liter v8. Trailer 1 weighs 4200 lbs (dry). Trailer 2 dry weight is 5600 lbs. Is there a way to know how much impact the additional weight will have on fas mileage?

[ASTMedic]

Originally Posted by Tevans1224

Hello. I’m new to the forum and apologize if this has been answered but I couldn’t find anything. We are looking at two trailers and the biggest difference is weight. I’ll be towing with a 2017 Ford F-150, 4x4, 5 liter v8. Trailer 1 weighs 4200 lbs (dry). Trailer 2 dry weight is 5600 lbs. Is there a way to know how much impact the additional weight will have on fas mileage?

More than just weight will change MPG. Frontal area of the trailer will add drag thus use more gas to keep it at a given speed. It's going to be hard to calculate the difference but I'm betting it wouldn't be as much of a difference as you'd think.

[kdauto]

Originally Posted by Tevans1224

Hello. I’m new to the forum and apologize if this has been answered but I couldn’t find anything. We are looking at two trailers and the biggest difference is weight. I’ll be towing with a 2017 Ford F-150, 4x4, 5 liter v8. Trailer 1 weighs 4200 lbs (dry). Trailer 2 dry weight is 5600 lbs. Is there a way to know how much impact the additional weight will have on fas mileage?

Nope, and I can tell you from experience.

6 years ago had this same dually gasser GMC and a 26 ft (29' overall) TT weighing 5500-6000 lbs loaded. It was 10'6" tall and 8' wide. We really felt the wind slow us down at times and I barely got 8.1 to 8.5 MPG average towing.

For the last 5 years we've had this 32' overall 5th wheel weighing 13 000 lbs loaded. It measures 12'8" tall and a wee bit over 8' wide. We get anywhere from 8.3 to 8.9 MPG towing. The 5er is more aerodynamic underneath with cladded,smooth underbelly vs the TTs exposed frame cross mounts. The 5er is closer to the truck cab so it is not breaking the wind again after the truck cab did. I feel a lot less turbulence tugging on the truck since we switched.

I improved fuel mileage approx. .4 MPG 2 years ago when I replaced all the suspension shackles and nylon bushings with bronze Mor Ryde stuff. Wheels are likely tracking straighter now and no more crack-crack sounds on tight backup manoeuvers.

I think aerodynamics is a major player, far more than weight. My buddy with a 5er and large boat concurs.

[Old-Biscuit]

Guess what....you're towing and MPG will be quite similar regardless of which one of those trailers is behind your truck.


4X8 sheet of 1/2" plywood vs 3/4" plywood
One is heavier but both act the same as 'wind sails'



MPG and Towing.....oxymoron

Hitchup and tow on top half of fuel tank

[tuffr2]

The direction of the wind will really affect towing mpg. Head wind towing will result in terrible MPG. Towing with a tailwind will result in pretty good towing MPG.

I towed a 5,500lb travel trailer with a 5.0 litre Ford F-150. My trailer did not have an areodynamic front. I got between 9.8mpg worse and 12 mpg best. Typically 11 mpg would be a good estimate.

[Whitewolf]

The above 4 posts each make perfect sense. Me thinks you're worrying much about nothing. If 'Trailer 2' is 1400 lbs more, I'm thinking it must be longer. Personally I think longer is better.

Your mileage may suffer a teeny tiny bit. But I believe the more room while your parked will offset any mileage decline you might experience. Even if your full-timing.

It's not just about the journey, but also the destination.

[Wrktfsh]

I tow with the same vehicle 2wd. 5000lb gross trailer. I get 10-11 mpg towing it

[Tevans1224]

All, thank you for the feedback. Based on this I bought the heavier trailer because it was preferable in all other respects. I can’t wait to pick it up and get camping! Thanks everyone.

[Whitewolf]

Good for you! Happy camping!

[rgvtexan]

Years ago, I used a slide rule for such calculations. Now I just keep track of the mileage with a spreadsheet.

Put the fuel in the tank and go.

Welcome to iRV2.

Enjoy your toys!

[CecilD]

Originally Posted by Tevans1224

All, thank you for the feedback. Based on this I bought the heavier trailer because it was preferable in all other respects. I can’t wait to pick it up and get camping! Thanks everyone.

Congratulations. Most of the advice you will get here regarding fuel economy due to weight will be anecdotal, as it should be. You did the right thing and bought the trailer you wanted. Welcome to the forum.

[mtofell]

I've been surprised at how minimal a difference different size/weight/type trailers make with respect to MPGs. I went from a 26' 7000# TT to a 35' 11,000# 5th wheel and I don't think it's even 1MPG. As others have said, wind can make a huge difference. By far the best thing you can do to lower fuel usage is slow down. Whenever some guy hauling a 40' trailer blows by me on the freeway at 75 I always figure it's the same guy on here micromanaging and complaining about MPGs

[seaeagle2]

70's F250 Camper and Trailer Specials were notorious for getting about 6 to 8 mpg towing, and 6 to 8 mpg empty....