Towing a vehicle and gas mileage


I’m renting a U-Haul truck to move 1300 miles and am trying to figure out if it would be cheaper to also rent a car dolly to tow my car or drive the car separately. The U-Haul site says the truck will average 10 MPG, but how much will it get if towing a vehicle? In other words, will towing cut the MPG to half or 5 MPG???

Thanks for any help or insight!


How big a box on the U-Haul? Im suprised they say it will get 10mpg. Does U-Haul say OK to tow a (I assume you will be using a car dolly with only the towed cars rear wheels on the ground) dolly? How big is the car you want to tow. How big is the trucks engine? gas or diesel?


Towing will likely only cut about 1-3MPG. Cars/dolly do not weigh much and the trucks with your stuff are very lightly loaded unless you have lots of tools or other dead weight.


With the biggest rental truck, 8-10 mpg is probably a good estimate. I bet the car will cost, at most, a couple of mpg, low end if it is flat and more if mountainous. Doing the arithmetic with a 30 mpg car and 2 mpg loss (8 down from 10); you will only save about $45 in fuel. A dolly or transporter will cost, you tell me, $150? Fix my calculations if necessary. Money wise, cheaper to drive both unless you add in wear and tear on the car. It will probably be an advantage to have the person that would otherwise be driving the car in the cab with you. OTOH, maybe not. The other possible down side is you can get a lot of stuff thrown onto the car and get stone chips. Have you ever followed a truck at 5 feet for 1300 miles?

I would get a dual wheel trailer rather than a dolly. You can back it up. You can see the wheels of the trailer in the truck mirrors. (With a dolly you can have a flat and ruin a tire and a wheel, heck, you can lose the whole dolly and car and not notice if you have a big truck.) You will save some wear on your vehicle over a dolly. You will have another set of brakes making it safer.

I towed for 2100, 2400, 700, 670 and 300 miles. It would cost me the difference between the dolly and transporter in Rolaids.

It has been about six years since my last rental. I found that you can bargain with the companies, especially with the mileage and days if not the price. Call everyone and then call back the company you want to rent from and tell them what the other guys are quoting you.

I have had good (fast) trucks and real (slow) dogs. I wish I could say how to avoid the dogs, but I can’t. Fortunately the slowest one I only had for 670 miles.


There’s no way a loaded UHaul, large truck, is going to get 10 mpg. My 3/4 ton Dodge gets about 14 towing a boat if I take it easy on it, 12 if I’m running 80 with it. A large UHaul probably gets more like 7 or 8 loaded. I doubt a trailer makes much difference with it. I will say that unless you have experience driving that size truck, you are better off not to tow.

I agree with the flatbed v’s dolly. Dollys are a pain in the tail to tow and many cars, particularly AWD’s and 4wd’s can’t stand being towed like that.



A U-haul truck will get bad enough miles. If your using a 15’ truck or better, they can more than handle the tow dolly for FWD or the car hauler for RWD and 4WD. And, it will not affect the truck’s fuel mileage that badly. You’ll definitely use more fuel by driving both vehicles. Go in peace.


You will definitely save money by towing. You are running one engine, not two. Maintain a constant speed on the interstate and your truck’s mpg while towing will not be much different from driving the truck by itself.


I appreciate your feedback about the 10 mpg. I’m renting a 14-foot truck and the U-Haul website says it will get 10 mpg, but the proof will be real-world driving.


The quote on the rental of the car dolly at the local rental place was $182, but the online site quoted $121 so your estimate of $150 is in the ballpark. I agree it might be cheaper to drive both the truck and the car plus fewer headaches of driving a very long rig…


Ah yes, the devil is in the details. Renting a 14-foot truck and yes, the car dolly means only the rear wheels are on the ground. The car is an AWD Subaru and from the other posts, it sounds like it is not a good idea to tow this particular vehicle on a car dolly. Good question about the truck’s engine and gas/diesel. I’ll do more research.


“The car is an AWD Subaru and from the other posts, it sounds like it is not a good idea to tow this particular vehicle on a car dolly.”

Unless you want to do some very expensive repair work on the center differential and possibly some other components in the AWD system, your Subaru should NOT be transported on a dolly. It can only be safely moved on a flat-bed, and that would add considerably to the weight that you are asking the truck to tow.

(Note: On some Subaru models, there is a fuse that can be inserted to “convert” the vehicle temporarily to FWD, and this would allow you to mitigate the damage from towing it on a dolly.)


Maintain a constant speed on the interstate and your truck’s mpg while towing will not be much different from driving the truck by itself.

I will only add that if you are trying to maintain 70 mph with that truck while towing, that extra speed is going to cause quite a hit.  If you can safely keep it at 55 it will make a big difference and only one or two mpg will make a big difference in $$$ . Exactly how much depends a lot on the truck and the engine.  The more you push the engine the lower the efficiency once you start getting up to max.


The 14 Footer appears to be a Ford 350 van. It will either have a 6.0 Navistar diesel if it’s older than 2007 or a V-10 gas engine in it, or I guess a 6.4 Navistar diesel if it’s 07 or newer.

The 6.0’s in a pickup empty get about 18 on the road. The 6.4’s in a pickup empty get about 16 to 17 on the road. The V-10 aint close to the diesels.

With the big box truck, you’ll have a lot more weight and a lot more wind resistance. I’d suspect 12 empty at best. Loaded, expect between 7 and 9. One thing to consider is will the weight of the car + trailer + truck + stuff in the truck get you over the GVWR of the truck. The GVWR of that truck is probably around 12000 lbs. The truck itself will weigh in at around 8000. That only leaves 2 tons of furniture and car on the back. I have a doubt as to that truck’s ability to be loaded and pull much of a vehicle behind it from the weight stand point. The larger 24 and 28’ trucks should have GVWR’s up to 26000 lbs.



From experience, if it’s a 6.0 L Navistar in a Ford, it will likely be geared to run 70. For that engine, speed doesn’t make a whole lot of difference. They have some Chevy Chassis as well, and it may be different with them. The 6.0 doesn’t reach it’s power band till it gets to about 2200 rpms which is around 70 mph depending on gearing. The truck could have a real low gear and reach it before then, but unlikely.