i just tried reading the manual and searching but couldn't find a direct answer.

i'm planning to replace my tires soon. the width, aspect ration, and diameter will be the same. just different brand of tires.

do i have to reset anything or will the navigation learn it automatically?

thanks.

If the size of tire is the same, why would you think you need to do anything at all?

Do nothing...

because i remember reading on this forum about resetting something after getting new tires because since you have more tread on your tires, it will throw the gps off. i don't know. that's why i'm asking.

wow

The difference between the diameter of a brand new tire and a tire that is worn completely bald is probably not even enough to throw off the mph reading more than 1 mile per hour...

Even if you change tire size, you don't have to do anything to adjust the NAV system. If you're not using the VSS wire then the system calculates speed based on the distance travelled (determined from the satellites) and the time taken to travel the distance. If you are using the VSS wire then you would have to adjust the car's computer to correct for the different tire size because the car's speedometer (and the VSS pulses to the NAV unit) would be incorrect.