Realilistic mileage with a fifthwheel.

[grizz272]

Just curious what kind of fuel mileage I can expect with a fifth-wheel.
1ton 4x4 duramax srw 36 Ft. 13Klbs fifth-wheel. I realize weather, road conditions whether it is flat or hills or mountains all can make a big difference. Generally speaking flat lands like the whole god forsaken state of Illinois.

[Bigg_Al]

Cummins12V98 wrote:

racer4 wrote:
10.5-12 mpg at 62 mph with 20,000 miles on the odometer.

I question this also!

+1

[fj12ryder]

Wow, 10.1 average mileage. Hard to believe that a 454 would get a high of 10.1 mpg pulling a 9,000 lb. trailer, let alone get an average of 10.1 mpg. That means at some point it got 11-12 mpg so it averaged out at 10.1 mpg.

We may have to agree to disagree about this one. 🙂 I owned one of them in a 3/4 ton truck and it was lucky to get 10 mpg running empty. Strong engine, but very thirsty.

[CampingN_C_]

I sure wish my old 454/4.10 Suburban would've got that kinda of mileage towing, more like 6-7mpg. It didn't get much more than 10mpg by itself. You definitely have a rare one.

[Impulse24]

1996 GMC K3500 (1 ton Dually crew) With Vortec 454 and 4.10 rear end. Magnaflow exhaust and Aero flow wing. No other mods.
2017 32 ft Crusader Lite Weight (9k lbs) 5th wheel.
Approx GVW 14 k lbs +/- a few.
Just completed a round trip from LA to St Petersburg Florida, total 5250 miles.
Drove I 10 going I 20 return.

Speed 55 - 60 mph, Average MPG 10.1.
Average fuel cost per gal $2-03,(hand calculations)

Previously we had a 36 ft diesel MH with a Cummins 5.9 and averaged 9.7 mpg so out of interest I noted average Diesel costs were running around $2-40.per gal

It was also noted that we were passed multiple times by the same vehicles ? Which raised the question of were they stopping more frequently for fuel or taking a lot of breaks due to stress ? And even though the GMC has a 33 gal tank we stopped every 250 miles for a break and fuel.

So taking into account Maintance costs in comparison to a Diesel, and a gas engine requires more frequent servicing schedules, for me ecconomy is on the side of the 454.
And judging by all the other posts Gas verses Diesel is not far off being equal in MPG results !! Although I admit more torque helps going up hill.
But I am surprized this topic has gone so far? Because when MPG has been brought up previously the standard answers are. I have better things to do than plod a long and if you have to worry about trivial things like fuel costs and mpg then you can't afford to RV. Ah well I guess a Leopard can change its spots !!

[Cummins12V98]

I just completed a 1,300 mile tow yesterday from SoCal to DFW, TX. I towed at 70 during the night and 75 during the day. YES my tires are rated for that speed. Including two 2 hour times stopping during the night having my high idle set to 1,000rpm to protect the engine and keep heat in the cab. My fills were to the top and hand calculated to between 7.5 and 8.0. Truck did not shut off during the 27 hour trip. Combined weight 33K.

[Cummins12V98]

ReneeG wrote:

Cummins12V98 wrote:

ReneeG wrote:
We average 12 mpg at 65mph.

Sorry but I would like to tow side by side with you and compare fuel used!

Wouldn't be an accurate test - two different TV's and two different FW's.

NOT saying you should be the same fuel used, I am saying 12 "average" @ 65 is VERY high especially for 24-26k combined.

When I say average I fill EVERY tank to the top over many tanks. The faster you go the more fuel is used plain and simple.

[ford_truck_guy]

I remember those "Good Ole Days" towing a 10k trailer and getting 12 mpg..

Now that we DRAG a 13'4-1/2" tall billboard down the road, all bets are off

[Cummins12V98]

allen8106 wrote:

Cummins12V98 wrote:

ReneeG wrote:
We average 12 mpg at 65mph.

Sorry but I would like to tow side by side with you and compare fuel used!

Sounds about right. During a two week vacation to Oregon and back we averaged 12.1 towing 10,500 lbs 5ver at 65 mph. Hand calculated.

Towing at your weight range I would get that type of milage at "times" also. BUT you are not near our weights and I am wondering if you are as tall or wide?

[Cummins12V98]

racer4 wrote:

Cummins12V98 wrote:

10.5 is the HIGHEST hand calc i see towing at 60 near sea level with no winds. My tanks range from 7.5-10.5.

I am talking AVERAGE over many tanks, NOT using the display.

NOT calling you a liar but this seems very unrealistic even with you I am guessing grossing at 26k or so compared to my 33k.

I am wondering what makes the difference?

Our trucks are mostly the same. You mentioned your higher weight. Other factors might be that you (I think) have two more tires (triple axle) and your FW is taller at the rear (less aerodynamic).

Mine is double axle. Maybe you got a GOOD one???

[Toolguy5]

I get between 12 and 13 depending on speedand how much climbing.

[ReneeG]

Cummins12V98 wrote:

ReneeG wrote:
We average 12 mpg at 65mph.

Sorry but I would like to tow side by side with you and compare fuel used!

Wouldn't be an accurate test - two different TV's and two different FW's.

[happycamper1942]

12.5 to the Canadian gallon which is 10.4 to the USG.

[ReneeG]

allen8106 wrote:

Cummins12V98 wrote:

ReneeG wrote:
We average 12 mpg at 65mph.

Sorry but I would like to tow side by side with you and compare fuel used!

Sounds about right. During a two week vacation to Oregon and back we averaged 12.1 towing 10,500 lbs 5ver at 65 mph. Hand calculated.

Towing the same FW with an F250 6.8L V10, we averaged 7mp!

[43tutor]

I tow a 2012 34' 5'er with a loaded weight around 11,000 lbs. My truck is a 1996 F250 with the 7.3L and a 4.10 rearend. Last trip out, in the foothills of appalachians, mileage was 12.3 mpg while towing at 65mph. I've made some upgrades to the truck to improve the mileage, before upgrades it averaged around 10 mpg in same towing conditions.

[mr__ed]

rhagfo wrote:

Earl E wrote:
Yep. 8-10 no matter what you are towing.

You must do all your towing at 70+, my 01 Ram gets 10 to 12 towing close to 12k. I would not expect much of a change going to a newer Ram.

Agree. I was getting about 11 MPG towing a fiver close to the weight of yours. using a 2007 3500 Ram one ton with 6 spd stick shift, SRW, forget the rear ratio, but it was under 4.0. That mileage includes all kinds of terrain. I was also a pretty conservative driver, usually cruising at about 60 MPH.