best tow MPG to move 3500lbs - dodge cummins or small car??
 

Under the theory and discussion that vehicles which are overloaded will tend to get poor mpg...

If I had to move around 3500lb trailer loads on a regular basis, do you think I would get the lowest cost per mile using a small vehicle and pushing it's limits (driving slow is fine), or a midsize V6/compact pickup which would be around the middle of it's limits, or a full size diesel pickup which would be understressed and barely feel it?

What about at 5500lb trailer loads, do you think the small pickup (this is about the top for v6 minitrucks i've seen) or the cummins would have a better cost per mile? (not necessarily mileage with diesel costing 30% more around here)

What about for very light loads with utterly horrible aerodynamics? (stacks of styrofoam walk in freezer insulation stacked up 13 feet high on a trailer) I'm trying to get a feel for how different tow configurations have for mileage.

i have a E-350 with the 7.3 turbo diesel, that always gets 15-17 mpg 15 is 80mph towing a #7500 trailer terrible aero. 17 is empty trying my best to save fuel.

a 2wd tacoma with 4cyl. is rated for #3500 tow if it has trailer brakes. but with a real load the diesel van is better mpg.

some of the cummins are getting 20+ mpg without trying, and #5500would not overload it. or drop mpg much.

unless you are using it as a daily driver and only occasionally towing, the diesel makes the most sense

you are going to 'jack up' the car.
The problem is the stress you put on all the attachment componets of the car. Not just the mounting points of the hitch. The suspension, tranny mounts, motor m0unts, etc etc.
Very few cars are made on frames anymore. they are unibody. So the stress of pulling that load are magnified thruoghuot the unibody.

That is a classic pound foolish example.

It's not a question about vehicle stresses, it's a question about mileage. :)

I know a guy whose a CAD engineer who made some special one off hitches and vehicle mods so that he's been pulling 3500lbs with a compact for over 50,000 miles of road time with no problems. So the vehicle can do it - the question is at the end of the day who is likely to have the mileage advantage...

Mcrews has a very valid point, it's not just the hitch, it's the engine mounts, drive axles, breaks.
We tow a 3,500 pound trailer at work with a Dodge 1500 and replace the breaks every 15,000 to 20,000 miles, we also get 9 to 11mpg with the trailer and 15-20mpg without.

My Honda Civic is only rated to tow 1,000 pounds and towing that my mileage drops to 35 to 40mpg, getting up to speed is ok but stopping takes planing and going around corners where the road is wet or sandy can get sketchy, I also notice that the car runs differently after I do a lot of towing, it ends up feeling like it's aged, that doesn't stop me from using it that way but it's something to keep in mind.

For towing I'd like to try one of the small Sprinter vans.

Well... still about mileage. : D I'm aware towing is hard on something especially something being pushed, but this will be a job for a beater econocar. Plus it's still comparing that to a V6 minitruck and a fullsize diesel for the 3500lb level. It's v6 minitruck or diesel for 5500lbs.

If your towing 1000lbs and getting 35mpg thats i'm assuming better than any cummins. Though at 3500lbs thats alot more - it's entirely possible that a cummins wont even feel that and will still pull 20mpg, whereas the v6 pickup will see some strain and maybe only be 20mpg itself. (but with 30% cheaper gasoline instead of diesel) At 5500lbs maybe the v6 pickup will be dropping way down. Or maybe it will be no worse off, mostly being about the aero load?

I'm trying to figure out which combination of two vehicles best meets my range of trailering goals. It's quite possible that a compact which can tow better than most (bigger than geo metro for this reason) and a fullsize pickup which is understressed is a better combination than say, geo metro and V6 S10 if the latter has to be used for nearly all tows over 1000lbs. Similar to the charts of "how does mpg improve when you cruise at slower speeds" from 35mph to 75mph, i'd be curious to how much the MPG of each type of vehicle drops as trailering loads increase. I've heard of enough gas pickups getting 8mpg towing travel trailers for instance. Someone said they got 8mpg towing 3500lbs with a sedan though because it was completely overstressed.

That mileage drop at the time went from 53mpg with an empty car and no trailer and 39mpg with a 10 foot long trailer hooked on 3/4 of the tank of gas and full about half that time.

The truck that we have at work has a 5.4L V6 and is towing a 16 foot flat bed trailer that we haul granite on, when the total weight is getting in the 3,500 pound limit then the truck really notices and the mileage drops down to those 8-9mpg figures and even with that truck driving in bad weather with that much weight gets sketchy.
A diesel would be well worth it.

Back in the late 70's, my DD was a 1955 Ford 1/2 ton with a 6 cylinder and 3 speed stick. At 50 MPH, it averaged 18 to 20 MPG running empty, and 8 to 10 MPG pulling the smallest U-Haul box trailer.

Which just reminded me....
2006 Kia sportage V6 FWD gets 24 epa on hwy.
Towed my daughters stuff to college. flat bed uhaul trailer stacker 6 ft high w furniture and stuff.
Actually could see the gas gauge move. got 9mpg on that trip.

Ask your buddy with the 50,000 miles of towing experience what his fe is and how everything is holding up.