Did not know that. I did know people who said they get 20+ were mostly full of crap. I can believe 15-18, but 25 would be a little too good too be true.

 

i think you two are referring to two different "trucks". the newer diesels do take a lot bigger hit on mpg than the older ones as far as i've seen. there are a lot of things on diesels these days that restrict the mpg but are there for emmisions purposes.

 

i'm referring to a 6.0. he was talking about a 7.3 so both relatively old enough to not be weighed down with emissions crap. and were talking about diesels with larger tires.

i never said stock diesels cant get 20+ mpg

 

ha i guess i don't keep up with diesels enough. i didn't know the 6.0 and 7.3 were that close in age, i know what body style the 7.3 came in but i didn't know when they started the 6.0's. anywho i know one thing that tricks people that throw big tires on diesels is the average mpg in the trucks computer. most people don't regear with a diesel so the computer is off and it will show you getting better gas milage with larger tires.

 

This is true. I know plenty of diesel guys who get decent gas mileage with large tires. Re-gearing your truck has nothing to do with how off your speedometer is. Hell, if you have a digital odometer you can adjust your speedo with a programmer anyways. Re-gearing changes your trucks final drive ratio, and will allow you to accelerate to speeds easier than your truck does with a numerically smaller final drive ratio. Also, any diesel will be "toned down" from the factory and efficiency can be improved greatly by merely tuning. The guy on here who is talking about getting 13mpg in his 6.0 probably isnt pulling enough RPMS at highway speed to maintain that rate. Re-gearing changes those things, but dont make it seem like I am saying that putting new gears in the truck is going to put you up to 20mpg with bigger tires. Bigger tires will always have a negative impact on fuel economy no matter what you do. More weight is harder to push down the road.

 

around here, that guy would have to flare his fenders to be legal. No more than 1" outside the fender allowed...

regards

 

Here in Mass those tires sticking out like that would get you a steep ticket and instant tow..
Plus no inspection station would give it a sticker without losing their license..



...zap!

 

Remove the outside tire and it is not sticking out anymore. Not sure how legal that would be though

 

Huge diesels are every where here. My buddy has an 08 F250 with 4" suspension lift and 37's. Guy I work with has a 72 chev with 6bt cummins 8" suspension lift on 39.5" tires. Nieghbour has an 09 f250 lifted on 35's. Another guy I work with has an 08 Dirty Max with 6" fabtech on 35s, the list goes on and on, literally. The biggest diesel performance place in Canada is near by us and almost everone with a diesel has been there. Smoke'em diesel.

http://smokeemdiesel.blogspot.com/



See the smoke'em diesel decal in the middle of the picture above. I plan to get a smoke'n diesels decal made to cover the back window of my truck if and when I ever get my L swap on my truck.

 

6.0's get worse gas mileage than the 7.3's from what ive seen

 

No law requiring flares here in MS as far as I know. The tires had to be close to 40s.

 

needs mudflaps too since its a dually

 

stock to stock yea i'm sure, probably a little bit but not 4-5 mpg difference. there is literally no way to expect someone to pull 21-22 mpg on a lifted truck with 35"+ tires. MAYBE get to 20-21 if they go 60 mph down the freeway, but going the average 70-75 hell no. i'd believe it when i see it.