Actual mpg after bigger tires?

How do you guys calculate mpg after lift + bigger tires?

I used to get 14-15 before lift/tires.
Now I get 13-14 3" Lift and 33's.

So my question is it sounds like im still getting similar mileage due to the overall diameter of my tires are bigger? Can someone calculate my mpg now to compensate for my bigger tires?

 

33.6" @ColoradoTJ

 

I have a 7" lift running 37" off-road tires. My truck was recalibrated for tire increase. I average around 12 mpg so far. Still running stock air intack and exhaust for now. Strongly considering the Supercharger to help with my lead foot. Lol

 

I'm averaging around 13 with a 3" lift and 35" Toyo OC AT2 Xtreme.

 

3.5" lift with 34.6" KO2's - 14.7 MPG after Hypertech speedo calibrator. To calculate the error without calibration, determine revs per mile for the original tires. Then revs per mile on the new tires. Calculate the difference in percentage, and thats how wrong your speedometer/odometer is.

The simplistic approach would be to apply that factor to your old MPG to determine what your theoretical new MPG would be, But really, there is no substitute for doing the math at the pump. Apply the correction factor to your odometer increase since last fill-up, and then divide it by the number of gallons used.

Adding taller tires does more than just change your effective gear ratio. Taller tires are heavier, and if they are more gnarly than stock, have higher rolling resistance. If your taller tires are associated with a lift, your vehicle drag is affected as well. Finally, changing your gear ratio (by adding taller tires) changes engine rpm at a given speed, and that certainly affects MPG. Again, there is really no substitute for math at the pump.

 

Excellent information!

So I know my speed is off by 5% according to that website calculator. So if I calculate 14mpg at the pump, do I add 5% to that to get my corrected mpg for my tires?

 

Is that pnp or there's splicing to be done?

 

Let's say your odometer says you went 300 miles on 20 gallons of gas. In that example calculated MPG would be 300 / 20 = 15. Since your tires are taller, you really went farther per revolution than your truck thinks you went.

So applying the 5% correction, you really went 315 miles, and the actual MPG would be 315 / 20 = 15.75.

Or to calculate it another way, 15 * 1.05 = 15.75.

Or to use your own numbers: 14 * 1.05 = 14.7

 

Thanks so much @bobeast !

Exactly the info I wanted.

 

..sounds like a Math guy to me....lots of folks don't know the short cut to calculate it like the way you showed above .