dflw_99 said:
thx
does anyone else have 31X50R15 on thier frontier
I don't know what that designation means.
Do you mean 31 x 10.5 / 15 ?
Looks like you're going from about 26" to 31".
That's a big difference: around 20% !
That should represent a 20% change in your speed (you'll be reading slower) and a 20% decrease in miles on the odometer.
Theoretically, you've increased your effective gear ratio (lower number: say from 3.73 to 3.00). That should give you poorer performance off the line, but better fuel mileage and a better top end.
Unfortunately, the "real world" observation seems to be poorer performance
and poorer fuel mileage (don't forget to take into account your odometer change)
and poorer top end. Maybe that's because of the greater rolling mass to overcome, or aerodynamics, or whatever else. I don't understand why it doesn't work that way and I haven't changed tire size significantly enough to have any personal experience.