hey guys, im looking to see how much gas mileage i should expect to lose with 285/70 R 17's instead of the stock 265/70 r17's on my truck. ive been looking for nitto terra grapplers and the smallest size the guy where i can get em through is 285's (which would probably fill out the fenders better), and im not really looking forward to losing much for mileage since i only get 15-16 as it is. or since im getting a CAI and doin some exhaust work, should MPG still be about the same with the 285's? on the nitto site it says theres 23 less revs per mile as well(on the 285 compared to the 265), but is the mileage lost with the more tire to turn during acceleration? oh and i have a 3.55 LS rear end as well.

thanks guys
Adam M

 

With my old F150, I added Michelins that were 1/2 in taller than the original Generals, and I noticed a loss in acceleration and mpg. This is also taking into account speedo re-calibration.

As for mpg, I went down almost 1 mpg.

 

I went from stock 255/65/17 with an average of about 13.5-14 ampg in the city and roughly 18 on highway, to Nitto Terra Grapplers 285/70/17, which is a great tire! Now I get about 12.5 mpg in the city andaround 16.5 on the highway, if i don't speed much. I also have the AS2.5 and AAL springs.
Also the nittos are a heavier load range tire.

 

It has more to do with the tire weight than diameter difference. Yep, 1-2mpg after corrected odometer.

 

wow, i was expecting a little more than that, a friend of mine went from 255's to 285 cooper st's and lost 3-4 MPG. 1-2 aint bad, and hopefully i can see the same img etting now with some mods. here i come terra grapplers....

 

I went from the factory 265 Goodyears to 285 BFG MTs and lost between 1 and 2 mpg. Well worth it though (in my opinion)

 

ill be doin the same but with a different 285. 1-2 aint bad, better than i thought, well it looks like im orderin some tires tomorrow!

 

The gas mileage loss depends on a number of things. The size of the engine, gear ratio, and the driving style. The 5.4L will not have to pull as hard to turn those tires as say the 4.6 or even the 4.2. Less strain=lighter engine load= better mileage. The gear ratio really speaks for itself. A 3:73 will have an easier adaptation than a 3:55. If the driver guns it everywhere than certainly the mileage will suffer but if you are fairly easy than it won't suffer as bad.

Just my 2 cents

 

I will be going from 265's to 285's or 305's how bad do you think it will hurt! This truck never seen more the half throttle!!! 1/4 throttle most of the time! It's a bone stock 5.4 99 4x4 f150 reg cab 3:55 gears

 

I don't think it will hurt too bad. The look is definitely worth the sacrifice in mileage. Mine is a 5.4 with 3.73 gears and I have no regrets at all.

 

I went from 255/70/16 getting 11-12mpg's in the city. Now I have 285/60/18 and get 10.9-11 mpg's in the city. If anything I probably lost 0.5.
2002 supercrew
3:55LS
2wd
5.4L