New Ridge Grappler Size 255/80R17

Update in case anyone is still interested in these tires.
Just completed an 8hr round trip drive on these tires. My odometer is still not calibrated so I had to use my fingers and toes to do the calculations.

1st readings:
Odometer distance: 244 miles
Actual miles: 258
Gallons of fuel burned: 14
Tacoma computer MPG: 17.4
Actual MPG:18.4
*fair amount of crosswind during the drive
**drove on country roads between 55-75mph and a fair amount of "flooring it" to pass slowpokes

2nd reading:
Odometer distance: 184 miles
Actual miles: 195
Gallons of fuel burned: 10
Tacoma computer MPG: 18.5
Actual MPG:19.5
*minimal wind
**drove on country roads between 55-65mph
***hit some traffic congestion and stop lights

3rd(in progress)
Odometer distance: 174 miles so far
Actual miles: tbd
Gallons of fuel burned: tbd
Tacoma computer MPG: 20.6
Actual MPG:tbd
*Minimal wind
**drove on country roads between 55-65mph
***no traffic- able to maintain constant speed uninterruped

What Im seeing at this point is that the sperdometer is showing roughly 5mph slower than my actual speed when im around 60mph and that the displayed mpg is consistently 1mpg lower than my actual calculated...so not far off.

Truck is on 4.88gears and drives great. Cruise control works too and doesnt do all the crazy gear hunting and redlining that it used to do. Overall- very happy with this set up

 

@D-Rex thank you for taking the time to post. Really great information that forum members should find helpful.