I have filled up with gas twice now and both tanks was just over 10 mpg. It has around 450 miles now. Once it is broken in, what can I realistically expect? 12 or 13 mpg in mixed driving. I know this topic has been beaten to death, but I have read some posts where the first few tanks were in the 7-8 mpg range so I have high hopes. I have the 4:30's with the 17 inch wheels which should be more efficient than the 20's. Those things are huge (34.0 inch diameter).

I still can't get over the difference in the drivetrain from my 99 V10. I have joined the BSEG club to say the least.

 

thats about what i got also with my 05 ,4:56's and 17 inch wheels /tires, and it might well be the av. till you hit what also seems to be the full breakin point at about 150 hours/7.5k when they fully come to life for some unknown reason.

i have a very well set up sctflash excal 2 tuner in mine with 25k now and do run a av. of 11.4 to 12.3 per tank mixed driving. other guys seem to av. that some do better. it all depends on how you can control your right foot and road weather condtions.
wish you a lot of good luck with your new ride man.

 

With 2700 miles on mine avg around 11.5....mixed.
Sometimes I will run it through the gears a bit, I dont think it's good to
putt around like granpa all the time.
Luckey you, the smaller tires with 4.30 gears, mine has the 34's with 4.10
Once mine is fully broke in and I yank about 10,000lbs though some hilly terrain
I'll determin weather I want to go with 4.56 or 4.88, most likely 4.88 then bump
up to a 35in tire when needed.
Oh, back to your question I'd say your gonna avg around 11.5-12.5
I find it very hard to belive anyone can avg 14....... with 4WD
I also had a new 99 V10 this 07 is much nicer!
I've also had a 7.3 and two 6.0's this 07 V10 is a keeper as of now.
I really dont think you'll need to much luck with the good truck that you have
Gene

 

I get constantly between 11.5 and 12.2 on my 07' with 4.10 and the largest stock wheel available, i think its 18" either that or 17." Durring the break in period though it only got 10. Now with 8878mi its constant 11.5-12.2mpg and thats driving very modestly with a 6spd

 

Mine started to get better milealge around 7500 miles and has gotten even better since. (currently at 29K miles). Be patient! It takes this guy a little time to loosen up.

 

Thanks for the feedback guys. This is a good thing that gets even better. What more could you want?

 

Did your truck come with the 20's? I have an '05 V10 SC 4wd 4.10 with stock 17" setup and I'd like to switch to the stock 20's but I've heard it will reduce my gas mileage. I currently get about 10.5 around town driving and 11-12 mixed.

 

I am considering buying an '07 that has stock 20' wheels as an option over the standard 18' KR wheels. Does the speedo need to be re-calibrated if I downsized to 18' wheels? I am not concerned about the change in fuel economy, this is more for looks since I don't care for the stock 20' wheels.

 

yes, if the diameter of the tire changes, you will need to have the speedo recalibrated at a dealership.

 

At a mechanical point of view your mpg should go up.
Taller tire = less motor rpm.
The thing is these trucks are like people...as in different, when it comes to fuel mileage.
They also have a sweet spot where fuel mileage is at it's best...?
Running a taller tire may put you beyound that spot...?
Which in turn will seem to the lug the engine and burn more fuel.
I think it's safe to say goin a bit taller or shorter with tires will not have
that much effect on mpg either way...?
Rim size means nothing! Other than Ford puts 34.1 inch tires on their 20in rims.
It least thats what mine came with.
Also it's my understanding 20in rims only come on a Highline, Outlaw, Harley.
I have a Highline.
I do like the taller rim and tire, wish it would have come with 4.30 gears rather
than the 4.10's I may change them out to 4.88?
No doubt 4.88 will burn more fuel, but I'm more intrested in power & tq rather than a bit more fuel cost.
I've yet to pull my 10,000lb toy hauler, my mileage may get better when
loaded with 4.88...? Which would be OK with me
Gene

 

I drive mixed mostly. The ruck is an 05 cc 4*4 sb auto 4.10 and gets 10.5-11.5 winter (warming it up eats gas and the hub are locked most of the time) and 11-12 summer. Highway I am avg 75-80 MPH, 90 MPH is not unseen. Light to light I do not mash the gas but I go (OK sometimes I mash it).

Just highway around 14


When I baby it I only get about 1 mpg more so I just gave up and drive how I want to drive. The first few tanks I was nervous because I could not get over 10 MPG and that was driving it easy to break it in.

I tow my jeep on an 18 foot open trailer. Total about 6500 lbs I am guessing. Towing I keep the speed down to 60-65mph. I get about 8.0 - 9 MPG. This is in Midwest flatland.

If you look at the MPG poll most of the V10s get about the same MPG for like vehicle configuration.

Enjoy your truck!