MPG difference- TT Vs 5er of same weight?

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CrosbyDave

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Hello all, first post here.

I've owned a TT and currently have a 1/2 ton towable 32' 5er.
When towing with my 2019 F-250 diesel I generally average 9-10mpgs, never anymore than that. (all stock, no truck lift).
With today's fuel prices and not knowing where they are headed I was wondering, when buying my next trailer if there is a noticeable difference in tow fuel economy between the two types.

My wife and I are in the beginning stages of shopping for our next towable- replacing a bunkhouse with a rear living- and the fuel crunch got me to wondering- is there much of a fuel consumption difference between a TT and 5er if the weights and general shape are the same?

I can see where air flowing over the truck and smacking the front of the TT would be an air flow collision to overcome.
I can also see that the 5er sticking up over the cab is also creating a wind block of a height variety.

And yes I know, a lot of people don't care and will pay whatever whenever the tank needs it- that's a great place to be, but not where my brain lives.
Trying to get the best use out of the money I've be entrusted with is part of how I was made.

Has anyone noticed a gain or reduction when switching from one style of towable to another?

Thanks for the replies.
 

tlmgcamp

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To avoid the "big wall" issue, would you consider a cap for the bed of the pickup and a TT? One with a little bump on top would give you more room in the truck and help get the wind up and over the trailer
 

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Oldgator73

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I don’t know what the science on this is. You see folks riding around with their tailgates down because they think it helps with the gas mileage. I ”heard that was not true. I was told once that using the A/C drops MPG. Also heard that was not true. I believe the best way to get the best gas mileage is how one drives and maintains their vehicle. If you drive 80 mph your gas mileage will suffer. So drop down to 55-60. Maintain proper air pressure in your truck and RV tires. Get regular oil changes and all the other maintenance suggested on your vehicles. Lighten your load. Don’t pack items you don’t need. When we had a 5th wheel, 37’, triple axle, I got 9-10 mpg pulling and 20 not pulling. Had a 1997 Dodge 3/4 ton single cab, two wheel drive, Cummins diesel, long bed, 5 speed manual. If I drove over 65 mph my gas mileage sucked. Below 65 I got 9-10 mpg. Driving 70-75 I blew tires on the RV and got bad gas mileage. So, in my opinion the driver is the biggest factor in what the gas mileage will be.
 

Lou Schneider

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Welcome to The RV Forum, Dave!

Travel trailers are less tall than 5th wheels with stand up height front bedrooms so the truck and trailer have less exposed frontal area, meaning they don't have to carve as large of a hole through the air. It's not just the frontal area but also the suction created at the rear of the trailer that determines the aerodynamic drag. Lower profile trailers have less of both compared to taller 5th wheels, the ultimate examples of this are the low profile folding trailers like the Hi-Lo that fold down to the height of the towing vehicle.

If you're towing with an Expedition or a pickup with a camper shell creating the same profile a travel trailer is inherently more aerodynamic than a 5th wheel combo. I have a 30 ft. Sunnybrook trailer (10,000 lb GVWR) and when I towed it cross country a few years back behind my 1999 Ford F-350 7.3 diesel pickup with a cab height camper shell it got 10-12 MPG at 65 MPH. 2 MPG may not sound like much of a gain, but it means you'll buy 20% less fuel than a rig getting 8-10 MPG.

On the downside, travel trailers are inherently less stable than 5th wheels. They're more sensitive to load induced sway and the hitch point several feet behind the rear axle means side forces on the trailer have a lever to affect the direction of travel of the towing vehicle. That's why they need equalizing hitches, sway bars, etc. instead of the simple drop and go hitch used by 5th wheels.
 

steveblonde

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When you get into 30ft plus units either a tt or a 5er driving conditions ie wind and hills or driving style ie under over 60mpg and proper tire pressures have more to do with mpg than it being a 5er or tt. Adding a topper or canopy to a puckup just adds 700lbs of dead weight to the pickup it will just lower the trucks fuel mileage it wont help anything- been there done that, owned several. When we added a canopy to the wifes truck to keep all the wakeboards and boat stuff dry and clean the mileage on her truck dropped. Payload on that truck was 1600lbs canopy weighted in at over 600lbs
 
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Gary RV_Wizard

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I'm with Steveblonde. The science is on the side of the TT with its generally lower profile, but the practicalities will overwhelm that in most scenarios. Major factors include driver habits like speed and braking, the effects of other traffic on your driving, tire inflation, weather, even terrain. I think the best you can say is that a TT has the potential to improve mpg IF you use optimal driving technique, maintain your rig well, and can avoid external negatives such as stop & go traffic.

I have a 30 ft. Sunnybrook trailer (10,000 lb GVWR) and when I towed it cross country a few years back behind my 1999 Ford F-350 7.3 diesel pickup with a cab height camper shell it got 10-12 MPG at 65 MPH.
Anecdotal evidence is interesting but not a reliable indicator. I towed a 10,000 King of the Road 5W with my 2000 F250 diesel and typically got 13 mpg. Even in the Rockies mpg never got down to 10. I don't think anybody is doing that well with newer diesels, though. The 2007 and 2010 EPA requirements really hurt diesel mpg.
 

CrosbyDave

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Excellent replies with plenty of food for thought.

I ran some numbers after posting and the cost difference for our next big trip was in the $500 range at 9-10 mpg vs 12 mpg at $6 a gallon diesel. A small number when considering all cost involved, but something to consider none the less.

Now I’ve got to play the pro and con game of each before pulling the trigger.
I’m wanting to rent a TT of the length I think would work then drag it up and down the highway to help remember what towing one of those felt like.

I’ve got another unfuel related comparison question- should I ask it here or start another thread?
 

Kirk

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Anecdotal evidence is interesting but not a reliable indicator.
True, but personal experience is a valid hint, even though not hard evidence even though no two situations will be exactly the same. On towing a travel trailer with a truck, my mpg towing a 4,000# travel trailer with a 2500 diesel truck increased by about 1.5 mpg when I added a shell in place of the original tonneau cover. It was a shell that is cab height all of the way back and is probably a foot lower than the trailer top.
 

Rob&Deryl

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In general, I got 10+ mpg over 9000 miles towing a 14,000 lb 5th wheel last winter. Better mileage east of Mississippi River vs west. We went all the way to CA from NH via GA.

Your mileage will vary.

My opinion is to buy the trailer (TT or 5th wheel) that suits you best from a floor plan and storage perspective and then get the right truck to tow it and be done with it.

How much money will you spend renting and testing? Put that money into your travels and move on.
 

John From Detroit

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Consider a Class A with a small towed.. Reason I say that.
Was talking to someone who had a 5er about the same size as my Class A. and of course a big honking pickup to pull it.. Ask him what his MPG was towing.. identical to my class a.

Ask him about his MPG running to the store for a loaf of bread.. (Teens)
My Towed 20-40 depending on conditions (55mph, freeway 39.8 faster it goes down about 26 overall my towed is not a small car but a Jeep Cherokee Latitude about 4,000 pounds as I go down the road.. Newer cars, and smaller. often get better MPG NOTE My jeep can not be towed 4 down but other models can (Different transfer case. Mine is "All wheel drive" (Full time 4 wheel)
 

old_toys

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my toy hauler is flat on the front. had a ARE bed cap on the truck when i bought it and got 9mpg towing it. traded the cap for an uplift topper and gained 2mpg.
 

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RFSims

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Buddy has a 37' Cougar 5the wheel with a 2016 GMC 2500 Duramax. I had a 2018 Rockwood Ultralite 34' @ 6400lbs dry. Pulled by a 2019 GMC 2500 Duramax. On a trip through the Rockies last September I averaged 12 mpg towing. My Buddy averaged 10mpg in the Rockies. I now have same truck pulling a 2022 Rockwood Signature 8337RL @ 9500lbs dry. The 3000lbs cost me 1 mpg.

With the trailers close to same weight the TT is 2-3 mpg more than the 5th wheel. That's not much if one would rather have a 5th wheel. My wife and I wanted a TT as we did not want the steps in a 5th wheel. If one is looking for fuell milage, I suggest they don't pull a trailer.
 

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John From Detroit

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Here is somethign to try.. Make a round trip... It is important it be a ROUND trip returning to the point of origin (This means any altitude changes are averaged out.. For example If I go EAST on I-69 I'm ging down hill enough to add an mpg or 2.. West I make up for it) Fill up before start (Same station) and at end and if you did any "Running around" while camped fill up again at the start of the return (Both times) NOTE how much fuel was used round trip.

Now wash and wax and do it again.
 

Pedro Dog

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Truck shells do not weight 600 or much less 700 lbs. Mine weights ~ 170 lbs (short bed Pickup).
Common sense says that a pickup truck with a shell towing a TT that is 8 ft wide and typical height, has less frontal area than the same pickup towing a 8 ft wide 5th wheel.

Science says that drag is directly proportional to the cross sectional area being towed. All other things being equal, the RV with the smallest cross sectional area will consume less energy to overcome the drag.

Only thing we can't really know, is the drag coefficient of the TT vs the 5fer. Those numbers are usualy measured in wind tunnels. This coefficient is also directly proportional to drag of area being towed. I would argue that the drag coefficients for the TT and 5fer are close and contribute much less to drag than the difference in cross section.
 

CrosbyDave

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Crosby Texas
In general, I got 10+ mpg over 9000 miles towing a 14,000 lb 5th wheel last winter. Better mileage east of Mississippi River vs west. We went all the way to CA from NH via GA.

Your mileage will vary.

My opinion is to buy the trailer (TT or 5th wheel) that suits you best from a floor plan and storage perspective and then get the right truck to tow it and be done with it.

How much money will you spend renting and testing? Put that money into your travels and move on.
I'm renting one to make sure I can get it beside the house where my previous (recently sold) 32 5er sat.
I plan on building an awning for this one to sit under so I have to take overall height into consideration as well.

The TT rental is set up for the 21-23rd to a destination along I-10 that's 160 miles away- it will be a mix of fighting my way through Houston and open road without much wind blockage.
Not only to check fuel mileage, but to recall how they feel to tow and back in and what not.
So far I'm only out <$300 for the rental, I'd much rather spend that and go on a quick trip than just hope I like it after the purchase.

We've went shopping and have some picked out that would suit our needs.
Right now a TT is making more sense for multiple reasons, we will see how it goes.

Thanks for all the positive comments.
 
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MoInEd

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Edmonton, AB
The biggest issue in increasing fuel consumption when pulling a trailer is the drag (air resistance).
I made a wind deflector for my car (documented here 1585 Lincoln Avenue, Port Coquitlam, BC, House For Sale) and noticed it helped with fuel consumption around 10-15% easily. I since changed our travel trailer. The wind deflector was designed for the previous trailer (the line of of the deflector going above the trailer). The new trailer is a bit taller and heavier. I still get better mileage with the deflector but it is not as good of an improvement as the previous trailer.
 
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