Ok lets be honest for a minute lol!!! I am depressed to find that I am getting 7.75mpg towing, hand calculated. Granted, I'm towing heavy, 35WW, baja bug inside, 2 full size quads and a bike. But dang less than 8? 2005 dmax 6" lift 35" tires. Can someone please tell me they are getting worse mileage so I can feel better?

F-550, pulling 45 ft. WW 5er. 5.5 m.p.g. @ 75 m.p.h.
Hope ya feel better now

2006 F250 6.0 FX4 CC LB 33ft Attitude 5ver. Highway no trailer 17 MPG, Trailer 9.5 MPG. BFG 33 in tires.

05 discovery c7 cat 5 mpg towing 10k lb trailer at 75mph

'08 F450, 4:88 gears, towing 38' 5er weighing in around 14Klbs, I get about 6.5 on freeway doing 65 and 7.5 through the mountains (lots of ups and downs), my truck LOVES 50mph and thats when I get the best milage, at 65mph on the freeway my rpms are around 2700 and thats kinda high for a diesel, my top speed in the truck is 84mph, and I have absolutely no desire to go that fast in that truck, I have other vehicles to speed in...lol

04.5 Dodge CTD 2wd towing a 15k lb 37' Sierra, just under 23k gross combined. 10.5-11.5mpg @ 55-60mph depending on headwind. 20-23mpg for the commute (90% highway) at 60-70mph.

Speed destroys mpg. Did you recalibrate your speedo after the tires?

2004.5 dmax 35 s all stock except the hypertech programmer towing 35 ft 5 ver I get 9-11 mpg ! but thats driving like my nut sack is under the throttle pedal , and any head wind and that starts going down fast .

no i didn't, trying to keep miles off the odometer i gave it .5 extra mpg for the mileage calculation.

06 F350 6.0l with 12" lift and 40" tires. I hand calculated it towing my flatbed with buggy on it and I got 14.5. Towing my hauler with buggy inside was 11.5. I have not re-geared the truck but it will stay in overdrive at 1500rpm at about 60.


My old truck was a little different. F250 V-10......5mpg towing!

You want to run the truck at your peak torque for you engine, so if peak torque is at 1800 rpm and your engine is spinning 2500 at 65 you would want to regear or get a over under.

Don't add mpg, add miles then divide. Your tires are about 13% taller than stock, so multiply your mileage by 1.13, then divide by gallons used. Since the number of miles on a tank can vary so much, that number can be off.

For example:

30 gallons on fill up, 350 miles on the odo:

350/30=11.6mpg.

However, with the 13% correction:

395.5/30=13.18mpg.

Or, with your example:

7.25mpg * 30gallons = 217.5 miles

but with 13% correction:

8.19mpg.

Still not that great, but doesn't sound quite as bad...

BTW, the "don't want to put miles on the odometer" thing is why I immediately passed up ANY truck that had oversize tires.

What programmer do you have on it? My 06 f250 w/37's gets about 7 towing the WW. No programmer. Sucks. How you getting 11.5????

01 7.3 gets 10.5 to 11 towing my 5yh wheel to the dunes at 70-75. No lift, 33" tires.

yes, that's how I calculated it. I was in the 6's before!!!

07 Duramax with a 26' Carson trailer "wet", 3000lb car. I get around 10mpg at 55mph.

thats why the thread title says "honest".......i'm not buying it.

Very interesting info here :-)

I average 8-9 MPG grossing out at 40k lbs with my F650 that has the CAT 3126B motor. I did do a little adjusting/tuning that picked up about 1.5 MPG. Average speed going to Glamis is 62-65 mph.

Yeah, I'm finding it hard to believe too. My stock 05 6.0 pulling an empty fs3000 got right at 10mpg's.

My 08 6.4l with 4.88's got between 5.6 and 7.2mpg's to and from Glamis this past Thanksgiving. It sure does blow. That's why I'm putting money away each week for next year.

Wait a couple more weeks until the 2011 6.7L PSD MPG info is released! Needless to say, this next go around on diesel powertrains is going to get REAL interesting, well at least for Ford ;-)

I have an 05 6.0... lifted 8" on 37's w/o regearing. I can pull 15-16 w/o the trailer, but towing an Attitude 23AK empty it drops to around 10 if I keep my foot out of it. I also have intake and 5" turbo back exhaust , but no programmer.

My 2008 F-450 4x4 Crew Dually w 4.30 gears towing a 40' Dune Chaser-Next Level with 2 slides loaded the combined vehcile weight is 32,400 lbs and some change @ 65 - 70mph from Anaheim to G round trip I have averaged with hand calculations 6.4 - 6.6 mpg with this while adding 16 oz of Cetane to each fill up. I sure wish the truck had a 100 gallon fuel tank cause stopping every 220 to 250 miles to fill up just sucks.
My Dream F-450 would have same set up with a 8.3 ltr Cummins backed up by a Allison 3000 series 6 spd trans with a Jake Brake ooooooh snap I think thats is how the 08 F-450 is built outside of the US, guess I gotta find one in Argentina and see if the Cali Smog police will allow it to be registered

Sounds like you need to find an 03-08 truck with a blown out drive train on the cheap and start a "project"

Have 2007 Volvo Vnl Haulmark Motorhome 40' with 29' Stacker 49,000 lbs total. 7.2 MPG which is lower than I was lead to believe I would get (9-11MPG)
Anybody out there have similar rig and what do you get?

'07 F-350 2" leveling kit on 35" all terains with a 38' fiver

Nearly all downhill one way to desert, nearly all uphill into the wind on way home.

average mileage 6ish.

07 F250 6.0 STELLAR FSAK38 FIFTH WHEEL rhino 5 quads 250gal water 50 gal gas and firewood 6.2 with 35" tires on 4" lift with correction for tire size but who cares if u worry about gas mileage u shouldnt be going to play kinda like having a baller boat and worrying about how much gas u burn

<------gets about 5 in my f-550 on a good day

2001 GMC 3500 crew cab dually. Only mod is a cold air intake. Truck has 256k on it pulls a CR3905. I get 15 driving around, 11.5 when I tow but it drops to about 8 in any significant wind. I tow in O.D. as much as I can usually 62-65mph keeps the tach around 2200.

05 Chevy crew, Duramax, 5 speed Allison, no chip, all stock except for different turbo elbow, blocked off egr.
03 Rampage 26', ~1800lbs buggy
~9 MPG fully loaded
~16-17 everyday empty
~15 loaded, no trailer, doing 75mph to G.

05 Chevy Suburban with duel exhaust and a K&N cold box pulling a maxed out Haulmark car hauler, has Tatum and two quads, plus all our gear inside. Scaled trailer at 6950#. Getting 10.2-10.5 mpg round trip, onboard computer calculated. Still not happy, I really want a moho to pull my rides.

I thought I saw an artical where you were able to drive one. If it was you, how was it? I love my 450 but sure wish I could do something about that milage. Maybe a Gear Vendor.

2005 F350 Towboss towing Ragen bh40 24k ave loaded 8.9 -9.2 over about 10k miles 62-64mph 2100-2200rpm. Can get 10.8-11 at 55 no wind.

01 F250, 7.3psd Auto. 4" lift with 33's. Tymar intake and modified stock exhaust. I get around 17mpg empty, and average 9-10mpg towing my 26' toyhauler loaded up. When I towed a fifth wheel I actually got around 11mpg.

06 crew cab long bed 4x4 LBZ duramax on 33" tires pullin 38ft of rampage 5th wheel. right in the neighborhood of 22,000lbs i average 8mpg. ive seen upwards of 10 with a tailwind and as low as 6 with a headwind. when im cruisin at 58-60 with tow haul on, the trans in 5th gear and the engine spinning about 1800rpms. tow haul programming wont shift into 6th gear until at least 65mph but i dont like towing the 5er that fast. i used to average 13ish pulling the ol 22ft warrior that i used to have

If I am driving right at 72mph I get 13-14mpg. If I throw the bike in the back and average 80-85mph I get 20+. Thats what you get for driving a six banger with uncomfortble seats though.

Truck in sig, 4:10's, 4x4, stock,except for full exhaust. Trailer weighs 16800# fully loaded, 25700# combined.

55mph, no wind, 8.7 to 10.5, depending on terrain.

65mph, 7 to 8, depending on terrain.

Love the truck!!! Great power, zero problems in 74K miles, and it works HARD pulling this SLC.

C-Ya!!

02 Chevy 2500HD Duramax Allison, 35" Mud terrains, all stock drivetrain, 30' Dunes triple axle tag, 8 mpg

05 duramax 4x4 6" lift 35" tires. Towing 38' sierra with a buggy in it. Going around 60 gets me 9 m.p.g.

06 f350 6.0 powerstroke with 4:30 gears

7-10 towing a 2008 weekend warrior cr 3905 fifth wheel

i gross at 26k

03 F550 towing or not its 5mpg

GMC with same engine here same weight but only get 6.5-7 setting the cruise at 60
I dont care I didnt buy the truck to have the best mileage or be the fastest up the hill.....I wanted handling and BIG brakes!!

05 Dodge Cummins 2500 short bed 4x4 35" tires. 34' "tag" trailer, total combined weight heading to G is around 21,000 lbs. I hit 10 M.P.G. once but normally it's around 8.5 to 9.0 not driving over 60 M.P.H.

06 Dmax 3500 DRW 33's with leveling kit towing 35' Ragen 5 th wheel with golf cart, quads, bike, 100 gal water-33 gal fuel, wood. 8-9 mpg. Unloaded-15ish I usually weigh around 23K combined heading out.

97, F350, 4x4, C/C, 7.3 P/S, 100% stock, 14mpg at 60-65 towing a 28’ 5th wheel and 16’ flatbed with a 4 seat LT V8 rail. Around town empty 20+.

I have a 2007 Chevy 2500 HD with the BANKS 6 GUN on level 2, also cold air intake and 4 inch exhaust, with our LE3705 fully loaded with water/fuel Polaris Ranger, 2 quads and all our crap I get about 9 going the back way through the 78 and Ocotillo....i get about 8 on the freeway with the water full because of all the damn grades on the 8 BOTH ways....if i stop on 4th street and fill water I can get close to 10-10.5 but that is not hand calculated....could possibly be better because I have 17's on the truck.

im the only one with a 7.3??

F350 37" tires 4:56's and a gear venders 3" exh air intake kit superchips programer im movin 20k lb down the road


19mpg crusin on the freeway unloaded 11mpg towing on flat ground 7mpg towin up in the hills (like thru norther ca on the way to oregon)


beats the hell outa the 5mpg i got with the ol gas F350, and the difference in power is beyond night and day. im happy with my big noisy diesel!

WOW this thread made me feel so much better today!!! Last weekend I got between 6-7 mpg. I was bummed thought some new stuff I added really screwed things up. I was driving much faster than usual and heavy wind. I go the back way to ocotillo sometimes also and fill up down below also. I also forgot about mialge change with bfg 285's, that helps a little. Oh by the way i tow with 2005 2500HD with ww 3905 with two sxs and quad inside, 3 dogs three people and two cans of beer( dont want to overload it) LOL

I've got a 2002 Chevy 2500 CrewCab shortbed with Edge Juice and 5" exhaust on 33" tires. Empty, I get about 16.5 - 17mpg at abouy 78 mph. Towing my 40' WW that weighs about 19,500 lb at about 65 mph (she doesn't like to go any slower) it gets about 8.5 - 9 mpg depending on wind and terrain.

I used to get 9.5 to 10 mpg with the same trailer on the same fwys. Once they switched over to ULSD, I think we saw about a 1 - 1.5 mpg drop across the board due to lower cetane rating. I did a 4300 mi trip once from CA to AL and back, and mileage varied from 8 to 10 mpg even though the terrain was virtually flat. The only variable was the quality of the fuel.

I got a 2008 F450 6.4ltr Chip, exhaust, intake, 488 gears, and a Gear Vendor overdrive. I tow a CR3905 5th wheel with rail and gear in it. I get about 8-10 due do the Gear Vendor on it. RPM at about 70-80mh an hour is about 2000. RPM at 70-80mh with My Gear Vendor turned off is about 2700-2800. Huge difference in RPM and and gas savings!! Only negative thing about the Gear Vendor is the Price!!

One thing i haven't read on here that you guy's should really keep a close eye on is TIRE PRESSURE on the truck & trailer. Make sure your close to the max on the trailer for safety and gas savings. On your truck make sure your not too much under what it calls for. That will make a big difference in itself!

Good luck to you my fellow dunners!

Excellent point! Tire pressure does make a difference!

Im so glad I'm notthe only one getting in the 6 mpg range with a 6.0 ford, I took my truck to ford and told them i was only getting 6.3 mpg the 5th wheel and they said there was no way i could be right, so they hooked up there computer and it said i was getting 5.8mpg at 55, they said sorry there is nothing we can due but try a programmer, I did it didnt help,