fuel mileage/big tires

[wildbill963258]

How many rpm's are you running doing 70? I run right at 2000 rpm's doing 70 and for a 7.3l that's the sweet spot if you run over 2000 rpm's then your fuel mileage will drop.

 

[Arisley]

2000 RPM's is 63 MPH on my truck.

 

[TrailerHauler]

4x4 and the height of the truck makes a huge difference, the higher you are the less aerodynamic you are. My truck lost a few mpg's when I swapped from 2wd to 4x4, don't think I've seen 20mpg's with my dually since. I'm going to be shooting for it this summer though.

 

[Jassman]

This is what I use when I changed my tires. It calculates the speed when you put your original tire specs in and then the larger new tires. I checked it with a app on my I phone and it was perfect. I tried this on my F150 that came with 275 55 r20's and I went to 275 60 r20's..basically a 32" tire vs the 34 thats on there now.

http://tire-size-conversion.com/tire-size-comparison/

 

[PDT1081]

yea bud so funny but your to late read a few posts ahead, and not complaing about mileage cause i want 4cyl mpg out of a big truck. but looks like the thread did produce an answer to my priblem. no i have 3:73 and like i said before cruise was set at around 68mph the entire way.
IMHO if your happy with 8-10 mpg theres something wrong with you unless its really got some mods thats understandable and if you notixe in the post evryone posts how much there getting if they really dont care cause "they own a big truck and it shouldnt matter what it gets cause its a big truck" then why did they bother to find out?
i dont mean to keep repaeating posts that people in the past have asked but couldnt find to many answers in the search tab so figured this is what the sites for,no?

People know what their truck gets for mileage because tracking it is the easiest way to know when a problem starts.

You will not get 20mpg with that truck. 35/12.5s, Crew cab, 4x4, winter fuel, the fact that you're getting 14mpg hauling a snowmobile is actually pretty damn good. If you think you need more range, get an auxillary fuel tank.