I just bought some 265-70-17 Nitto All Terrian and i love how it came out. I have a 06 f150 2wd 4.6 and i thought it was getting good gas milege. The only thing i have done to it was a front bumper and a exhaust but when i put the tires on i noticed the gas started sucking it down. I thought it was because i was about 3,000 miles over my oil so i changed. What do yal think?

I use to drive about 45 min away and get half a quarter and now just driving around today i wasted a whole quarter tank.

 

I have a 2004 SCrew with the 4.6 and put the Geolander 265/70/17's on mine. Fuel mileage fell 20% over night. The original tires, Continentals, carried a max air pressure of 44lbs. The Geos have a max at 35 lbs. Even at max pressures the Geos would suck gas. I'm now running 42 lbs of air in them and have most of the fuel mileage back. I have no odd tire wear and I've put about 20,000 miles on them like that. You might see what the tire pressures are as written on the side of the tire and max them out. If it's 35 lbs max, I'd add another 5 lbs and watch for any odd tire wear. You might also check them for heat. If they are running hot, not warm, hot, they have loads of rolling resistance and yer gonna have to deal with it. And remember, the tire pressure as it appears on the door jamb is for a nice comfy ride for the tires that came on the truck. Ford has never made tires and you need to go by the tire makers recommends. Most have a safety margin of 15lbs constant built in to the design. Running them at 10lbs over usually won't hurt the tires but you can end up with odd tire wear. Just watch them if you go over the pressure on the side walls.

 

could be the tire size difference has thrown the speedo off (slowed it) if the tire size is much taller then stock. You can get it adjusted at the dealer or buy a tuner and that would correct it.

 

did you use the stock rims? or aftermarket? how far do they stick out? whats your stock tire size? 265/70r17 is about 31.5 inches tall right?
do the stock tire size divide by the current tire size then times the mileage on that tank divided by the gallons used.

 

They are still on stock rims, the stock tire was 255-65-17. The highway milage seemed fine but the city sucked bad.

 

Any and all of these conditions will cause gas mileage to decrease:

1. Heavier tire
2. Heavier wheel
3. Taller tire
4. Taller wheel
5. Wider wheel
6. Wider tire
7. More aggressive tire tread
8. Any suspension lift

 

I seen a Volkswagen Rabbit Diesel for sale on Craigs List the other day.

 

Agree on these. I always see a mileage loss when I put on my winter tires, along with the winter blend fuel. That's the price of adding different tires.

Paul

 

First, I think you need to measure fuel comsumption a little better. Judging your mileage by the gas gauge meter moving "half a quarter" and from 45 minutes of driving is not a good way of doing this. Most people use MPG (miles per gallon). You also need to do this through several tanks of gas to obtain an average.

 

time for a re-gear

 

I moved up from a 255/70/16 to a 265/75/16 and that was enough of a change to warrant a speedo/odo recalibration. I too thought my mpg's went way down, as I was still using the odo miles as a reference, which was LESS miles then actual.. (until I was informed of that fact from this very site!!)

After I re calibrated the speedo/odo and I recalculated my mpgs, I was back to basically where I was at before..

This was way back in 2001 when I did all this, and my mpg's have been consistent ever since then. I'm on my third set of 265/75/16's.

Mine are "LT" rated tires, so the max psi for them is 50 psi. For everyday use, I run them at 40 psi in the rear and 44 psi in the front. When I tow, I bump them all up to 50 psi.

I get about 60,000 + miles out of a set of tires and when I replace, it's well before the tread is to the official 'wear marks' too... I see a huge falloff in tire performance when they get about 60% worn....

Anyway, like was said above, verify how you're computing your mpg's by dividing your 'actual' miles traveled by the # of gallons of gas used and do that over several tanks of gas that you will get your 'average' mpg..

I do know that in the 8 years I've been driving my truck, if I go 100 miles on the first quarter of a tank, then I'm right at my 'average' unloaded and mostly hwy mile mark. If I'm at 200 or so miles by half a tank, then I'm still on target.... What's interesting, is I can only go another 100 miles on the last half tank before the low fuel light comes on.. I'm sure it's probably due to the gas tanks design, as it's not a perfect "rectangle" by any means....

Anyway, you will probably find that once you get everything synced back up with the speedo/odo and calculate accordingly, things will be back to 'normal' again...

Mitch

 

well i havent done anything yet, i did see that my air filter was all messed up and i need a new one. I just know that the gas gauge is going down way faster then it use to. i usually drive all highway.

 

I put some big ole tires on my truck and my gas mileage went in the crapper.

I did notice I have a shorter commute to work now.
Heck, they even moved the grocery store a half mile closer.

 

But there has to be something wrong or something not right because all my friends have bigger engines and bigger tires and i get the work gas mileage. I think my friends lifted jeep with 37in and lift gets better. Do yall think it my air filter?

 

Your 4.6 has to work harder than if you had a 5.4. Having a bigger motor doesn't always mean better mileage. What gears are you running? How long since your last tune up/fuel filter? Basic maintenance will improve your mileage the most. No FRAM!