I'm considering going a bit larger on my tire/wheel size, and was wondering if there is an easy math formula to calculate my odometer error, if I know the speedometer error.
For example: my stock tire size is 215/70/15 (26.9"), and I may go to a 225/70/16 (28.4"), which would give me a speedo error of 5.8% (a 60 mph reading on my speedo would now actually be 63.5 mph), courtesy: http://www.miata.net/garage/tirecalc.html
I just want to be able to calculate gas mileage accurately.
If I multiply my odometer reading X the % error (.058), then ad that to original reading, I should get the correct mileage . . . right?!
For example: trip odometer reads 320 miles, so 320 x .058 + 320 = 338.56 miles.
This seams right to me, but I'm no Mathametician. Can anyone enlighten me?