Anybody??

 

my 2001 with 8" and 37's has 3.73's an i get around 17mpg highway as a comparison

 

Same here but Im running a 4 inch lift with 37s and get 16 to 17 being easy on it on the highway.

 

17 sounds pretty good. Anyone else?? Kinda figured there'd be be more people commenting.

 

I'm rolling on 315-75-16 Duratracs, I'm leveled with X-code springs, (raised the front end 4" and sits about 1" lower than a 4" lift) I average between 15-16. I also live in a very hilly area and have a lead foot tho.

F-350 (Ford F-350 Super Duty) | Fuelly

If I were you, I'd do the 6" lift and 35's or 37's.

 

I'm running 6" lift and 37s on 22s on my 2002 7.3 cc with 3.73s and I get 14.5mpg at best on the highway. I'm probably going bacl to 35s in a year or two. It takes a lot of power to turn them over with the stock gears and I want my power and mpgs back! I don't want to spend the money on gears. I would rather put smaller tires on. I can't answer your question about stress on the trans. Mine was recently rebuilt along with billet converter.

 

I have an 8 inch lift with 37s. Mine used to be a DD, now not so much. I love the 37s, but as stated before the mileage does suffer. I can get 15 mpg if i really take it easy. when I was towing my camping trailer out to Pocono last summer, (about 6000 lbs) i got around 10mpg. In my opinion not too bad for a large truck with no gear changes and towing through the mountains.

just my 2 cents

 

wow I love getting to drive mine on flat roads lol...when I was running 8" 37's on my truck I would see an average of 17-18 mpg hand calculated....I pulled a trailer and fully loaded with 10k lbs extra 800 miles and saw 14 mpg loaded....dont ask me how it happened...I was shocked too lol

 

No way I wouldn't do it. I'd be trying to get it optimized for best all around. I heard with 35s or bigger 4:10s or higher number wise is better .

 

37s with 4.30 gears will put you right back into the stock powerband and rpms (thats why im hunting for a blown up v10 engine truck as many came with 4.30 gears. id rather swap rears then gears. alot easier.) If I run my 35s with my 3.73s I get a solid 17 on flat ground at 65mph highway and I like the better pull over the 37s.

 

I've been on 37's with an 8" lift on my 06' with 373's for going on 6 years now and I have no issues other than ####ty mileage but hey I haven't driven it in 2.5 yrs just sittin in the car port looking purty...........

 

How are you guys getting such good mileage???? I live in south florida (as flat as it gets). I've got a leveled '02 CCSB on 325/60-18's with an 80/tow tune around town I get maybe and I mean maybe 12-13mpg. On the hwy I might be squeeze out 13.5-14mpg. So how do you guys do it????

 

It all depends on what you do with your daily driver. You get some serious rubber under there, you're gonna want to try 'em out off road. You're gonna loose a lot power with 37s and 3.73s, even on the street. I have a camper shell, full tool box, custom made cabinets full of recovery gear, so my daily driver is over 9k#. I only run 35s but went to a 4.30 gear. I never drive 80 mph, but I can walk up any hill without working her too hard.

 

Yep csipsd my 02 with 3.73s and 35s gets 16 to 17mpg highway so I dont complain much. Wish sometimes I had 4.30s for around town driving and heavy pulling but I just lock it out of od with the button and let it wind up.

 

You guys are killin' me with this " my lift and big tires and good mileage". On the other hand, I'm going to show my wife this thread so she can see that not only will a big lift and tires NOT affect my mileage but I'll get even better mpg!! Lol

 

MPG is mostly how heavy your foot is. If you like to spool it up from every redlight and hear the turbo then youll eat fuel. If your light on the foot most of the time and conservative on take offs and dont do 80 mph on the highway youll get better mpg.

 

exactly what Bob said, it's all in your foot, you can get great mileage out of a big truck if you're a conservative driver which most of us have been around the game long enough and gotten over our hot rod kid days....yes it's possible to get good mileage with big tires, I'm running 15" of lift and lift and still rock 16-17 mpg on the highway...I am going to regear to get my power back...but still doing pretty well at the current moment.

Chad

 

Ok guys here is a real world comparison. I just swapped out my 4.30 for 3.73. Got a complete axle from a friend to use out of a 04 truck.
Unloaded there is not much difference in acceleration. Boost is up a few pounds across the board due to the incerease in load on the engine.
The big factor is the RPM's climb very slowly. Cruising on the highway at 70 netted 1700 rpm vs the 2050 of the 4.30's.
Trying to accelerate at cruise made the truck smoke due to the slow RPM climb. Around tow under 50MPH you can not use OD as the engine RPM drops to 1100 @ 50. OD locked out nets about 1850-1900 RPM @ 50MPH
Now on to the towing. Took my car on a friends little open deck car trailer. Together the 2 weight in about 4k. Not a big load but very noticeable compared to the 4.30. On the highway at 60 the truck would want to downshift to pull a simple overpass. Engine was way off of it happy spot of
2k RPM. I am going to rebuild my 4.30's axle over the winter while the truck is in storage and swap back in the spring as i would not want to drive a stock gear truck with a tire that large again without gears.

 

Ok guys here is a real world comparison. I just swapped out my 4.30 for 3.73. Got a complete axle from a friend to use out of a 04 truck.
Unloaded there is not much difference in acceleration. Boost is up a few pounds across the board due to the incerease in load on the engine.
The big factor is the RPM's climb very slowly. Cruising on the highway at 70 netted 1700 rpm vs the 2050 of the 4.30's.
Trying to accelerate at cruise made the truck smoke due to the slow RPM climb. Around tow under 50MPH you can not use OD as the engine RPM drops to 1100 @ 50. OD locked out nets about 1850-1900 RPM @ 50MPH
Now on to the towing. Took my car on a friends little open deck car trailer. Together the 2 weight in about 4k. Not a big load but very noticeable compared to the 4.30. On the highway at 60 the truck would want to downshift to pull a simple overpass. Engine was way off of it happy spot of
2k RPM. I am going to rebuild my 4.30's axle over the winter while the truck is in storage and swap back in the spring as i would not want to drive a stock gear truck with a tire that large again without gears.

My 7.3 on 35s with a 4.30 gear has the same "happy spot". You didn't say if you run 35s or 37s etc... but you observations match mine.

 

I love a good debate, when the OP goes away for a month, and it don't matter anymore...

 

If you look at the different trucks you will notice some are 6.0 and some are 7.3. This in itself will account for different MPG's!