Tire size and Speedo Question

[davbell22602]

How does it work when changing tizes on a truck? Is it if you go smaller you be going faster than what the speedo says or is it the bigger tire size makes you go faster than what the speedo says?

I wanna go from the factory 245/75/16 size on the 3/4 ton to 265/75/16.

 

[RetroC10Sport]

Your speedometer will be 3.9% slow. So if you're doing 60 MPH, you're actually doing 62.3.

 

[davbell22602]

Your speedometer will be 3.9% slow. So if you're doing 60 MPH, you're actually doing 62.3.

Thats going to a bigger tire right?

 

[HotRodPC]

Taller tire makes the speedo read slower than you are actually moving since you are covering more ground at same rpm. Smaller tire makes speedo read faster than you are you actaully going since you are coveing less ground per rpm.

 

[dhamp]

Hey Dave, I always use this site as a quick way to check various tire sizes at one time.

http://www.1010tires.com/TireSizeCalculator.asp