Weight vs gas mileage?

Like others said, wind and speed will affect your mpg's more than anything else. Driving into a 30mph headwind at 65mph, I've seen around 6.7 mpg's. Give me a tailwind and it's up to 11mpg's. You won't see that big a difference with weight.

prichardson wrote:
As others have said; aerodynamic shape is a bigger factor than weight in reasonably level towing. Case in point. I tow both a large boat and a TT with the same truck. The boat is about 1000# heavier than the TT yet I get 1 to 2 MPG better when towing the boat.

I used to get 1-2 mpg better towing my Bobcat and trailer which is 3000 lbs heavier than my TT! I figured one time, that my TT took 135HP at 15K and 90 sw ft of frontal area to go 60 mph. The bobcat at 18K and 70sq ft only took 115. So 20 less hp. That adds up to a bit of fuel. A 25K rig at 70 sw feet also took 135hp, same as the 15K TT setup did.

Semis they figure a typical 18 wheeler is a 1 for mpg. A rig with a full aero pkg, same wt etc, will need up to 35% less HP to move the same load. A cattle hauler or other rig with lots of wind resistance, upwards of 35% more hp to move the same weight load.

The only place wt really comes into play, is pulling hills. Then it might take an additional 40 hp per 1% grade you want to hold 60 mph at when weighing 15K lbs, 45hp if at 20K lbs. Frontal area does not effect your holding x mph on hills. just weight.

Some other factors that effect the amount of hp, include actual tire wt, tread design, profile series, 65's get better mpg than 75;s which get better than 85's assuming the same diam, tread width, just a taller rim diam, ie 265-75-16 is worst generally speaking than a 265-70-17 for mpgs. The actual road surface, asphalt is worst than cured concrete which is better than green concrete. Gravel is worst than hard surfaces, but better than dirt.

Marty

IMHO if you are worried about a small difference In mileage you should not be doing this.

You do NOT by a truck for the MPG, and you SURE DO NOT buy a TT based upon it. Ask those guys who bought the "aerodynamic" TT how much really changed???

If you like that heavier trailer better....get it. Hope that fuel stays in the two dollar range. Last summer, at over $4.00, I whipped out hundred dollar bills to keep the 32 gallon tank full.

As others have said; aerodynamic shape is a bigger factor than weight in reasonably level towing. Case in point. I tow both a large boat and a TT with the same truck. The boat is about 1000# heavier than the TT yet I get 1 to 2 MPG better when towing the boat.

A 10,000-pound increase in GVW or GCW will increase fuel consumption by about 8.5% (0.55 MPG) and is
equivalent to a loss of 80 engine horsepower at 45 MPH (8 HP / 1,000 lb @ 45 MPH) on a 6% grade.

Some facts to consider:
• Proper tire inflation pressure is important for your safety and that of others. Maintaining correct
inflation pressure based on the actual tire load will also optimize tire life, vehicle ride quality, and fuel
economy. With a tire pressure 10 psi lower than the manufacturer’s recommendation for the weight,
fuel economy will drop 0.5%.
• All tires are least fuel-efficient when new. As the new tire wears, the rolling resistance decreases
and fuel economy improves.
• Most of the fuel economy advantage is obtained when the tread is 50% worn.
• Regular radial tires and fuel economy labeled

http://prevostcommunity.com/PDF/Motor%20Home%20Fuel%20economy.pdf

Frontal area is something my wife and I have talked about with the smaller trailers sometimes being closer to 7' wide vs 8' wide on the longer trailers. Realistically I would like to have a combination that gets an average 10-11 mpg. My gut feeling has been that 800 lbs of trailer weight behind a TV that is only towing 40-50% of max towing capacity would mean very little. Beyond handling any thoughts on whether a SA or TA affect mpg?

You might notice a mileage drop adding 2,000 lbs. but not 800.

Wind resistance, not weight, is the big killer. If you want to get better fuel economy, get a rounded, low profile trailer like a Scamp, Casita, Oliver, etc. I have towed a little Burro molded fiberglass TT with my '08 Highlander V6 and averaged 14.3 mpg on a long trip. A similar trip towing a 2011 KZ Escape E14RB netted me 12.3 mpg. Both about 7' wide. The Escape was probably 400 lb heavier, but the big difference was the greater frontal area on the squarish TT versus the rounded, shorter Burro. I'd really feel it in a strong headwind.

Everything matters and is the degree that you seem to be asking about

Aero (the Cx number) of the frontal and the sail area of the sides

The tires of both the TV and TT. What cype/class, rating vs actual weights, tread,
how aired up, rim width vs tire recommended range, etc

Pure weight affects mostly the getting up to speed and back down in speed and of
course inclines/altitude

Finally...the drivers right foot...AKA how you drive or your driving style

Performance is more important to me than MPG, though MPG is important enough to
be on my have to have list

Aero in that one trailer might have a better frontal profile than the other,
taller, wider, etc. Also on Aerodynamics...the undercarriage makes a difference
on MPG. Turbulence if there is lots of stuff down there to create vortexes

Personally, think the MPG differential will not be that big a deal for 'me'...