MPG decrease with 265/75r16

I have a 2014 tacoma 4x4 with 245/75r16 tires and i want to install a rough country 3 inch lift and put 265/75r16 Goodyear authority tires on. However i am worried about the decrease in MPG has anyone done this mod and if so could you tell me how much your mpg decreased. Any input would help. Also I'm curious on the road noise of the authority tires.

Thanks
Louisianaboy23

 

I have duratrac 265's(which are a little more aggressive than the authority tires) with 3inch ICON setup, and my mileage didn't decrease at all coming from 245 silent armors. I also cant hear my tires but I do have my radio on pretty loud most of the time

 

I went from 265/70/R16 BGF Rugged Trail (OR standard tire) to 265/75/R16 C-rated Duratracs and lost 1-1.5 MPG. Truck is effectively stock otherwise.

 

I went from stock rugged fails, to 265/75/16 Cooper ST Maxx, load E. I lost about 1-1.5 mpg. '14 4.0 V6

 

When calculating your MPG you need to factor in the difference in tire height from stock and add that into your miles traveled as the numerator.

Example: Trip shows 235 Miles traveled and 14.8 gallons. So 235x1.06 (since I run 33"s and they are 6% taller that stock) and get 249.1/14.8=16.8 MPG

That also means your speedo will be off by a percentage that the tires are taller than stock.

 

265/75/16 load C Duratracs here. I noticed a slight decrease in mpg as well as different shifting points.

 

In a nutshell... and you don't need a lift for them!

Going from 265/70-16 to 265/75-16:

You gain 1/2" ground clearance.
Your speedometer will read correctly instead of too fast.
Your odometer will read slower, about 1 mile for every 40 (10 miles per 400).

So, if you fill up after 200 miles on the odometer, figure your mileage at 205 miles.
You put in 12 gallons... so you first think you got 16.6 mph. However, if you adjust for the 1" taller tires affect, you find you got 17.1 mpg. Net change 1/2 mpg!

 

I lost 3 mpg

 

I lost one mpg. Just the tires no lift. Yet...

 

I have a very detailed spreadsheet on my MPGs that takes into account odometer error after a change from 245s-->265s. I have lost between .5 and 1 MPG. There are a lot of other confounding variables even with no other mods such as number of miles driven per season, etc.

 

I went from stock with 245/75 16s: 22 mpg to 2.5" lift with 265/75 16s: 20 mpg.
I can live with that. Still better than a full sized truck stock.

 

I went to 265/75/16 ST Maxx and lost 2 mpg. I tracked a trip with gps against the odometer and it was right on. Gas mileage aside, what bothers me more is the way the tranny shifts. In my opinion it doesn't get on it like it used to.