Quote Originally Posted by H3_VX View Post
Really? With only half an inch. I figured it wouldn't make any difference at all. Thanks.
Remember that the speedo is really just measuring the RPM of the tire & converting that to rate for distance traveled. Likewise, the ODO is just measuring the number of revolutions of the tire & converting it to distance traveled. It all boils down to the circumference of the tire which is directly proportional to the diameter (c=d*pi).

So ... the easiest way to wrap your mind around it is that the % increase you make tire diameter, your speedo & odo will be off by the same % (going from a 30" tire to a 33" tire will throw your guages off by 10%).

As a matter of fact, if you were to calibrate your speedo against a GPS with new tires, then again when the tires are used up, you should see a difference (small but measurable).