1010tires.com will give you the difference in speed with your tire change. Recommended tire change should not exceed 2%

 

well i bought a new 07 F150 regular cab V6 5 speed , brand new fisrt trip i got 980 KM out of my first tank, hwy miles i now get 1010 km out of a tank with 10500 km on it, thats about 625 miles to a tank of gas, i think that is dam good myself, city driving i get about 750 km , for a heavy truck i think it is very good, V6 definetly seems to a little underpowered but for what it is it is a great truck.

Cheers
James Beamish

 

Diesel; that's the same truck I have, but I haven't put enough miles on it to really get a good figure. It only had 3100 miles the first year (Jan. 2). At this rate it'll be three years before it's broken in. However, on the first day I had it I drove 100 miles each way to pick up a set of wheels with mounted tires for my SUV, and it got almost 21 mpg. I haven't had a long trip on it since, and I usually get 15-16 mpg. Does yours have the 3.31:1 rear? It's axle code 27 on the door sticker.

ETA: Underpowered by some definitions, but if you use the gearbox and let the V6 wind up it's a very spirited truck. My favorite thing on it is the brakes (4-wheel disc w/ABS) which are monster brakes.

 

Hay Saxman mine is a 355 ratio, do you have any problem lifting off when starting, mine stalls sometimes unless i slip the clutch a bit when on a little bit of a grade.

 

Mine is a 4.2, XL Reg Cab, Automatic, A/C, 3.55 rear. I average 20.5 on the road, having only picked up 1 mpg in 8,000 miles. I added a tonneau cover for appearance and a bit of security, and hoped that it might add a mile or two to the mpg. I found that the tonneau cover didn't affect the mpg at all. As an XL driver, I have to figure it with a hand-held calculator! Unlike my other "Panther- platform" Fords, I actually have to push the buttons! As far as being underpowered, it seems to be very docile, unless I "push" it, and then it seems to "come alive", not as alive as a V8, but not dead either!

 

let it be...Ford will charge ya about $100 to reset the speedo for the new tires/rims. FYI though, my SuperCrew gets 13-15 mpg in the city with the 5.4 and 3.73 gears. are you hotrodding the truck around town?