TopBanana
Junior Member
I've got an '05 2500 CTD 4WD w/ 315/70/17's on it. I purchased a Smarty Jr. which has the ability to adjust tire size. I changed the tire height to 34.4 when I installed the tires and assumed it was good. Fast forward to when GPS is available on your phone and it says my speedo is reading ~15% fast. I adjusted up the tire size by like 1.5" (can't remember exactly) to slow down the speedo and it only made a minor difference...now reads ~10% fast.
So do I have the right idea here... i.e. increase tire height to make it read slower? Have I just not increased he tire height enough and need to add 2" or 3" more to get it inline? Anyway to calculate the right number so it's not a crap shoot?
Thanks in advance for your help.
So do I have the right idea here... i.e. increase tire height to make it read slower? Have I just not increased he tire height enough and need to add 2" or 3" more to get it inline? Anyway to calculate the right number so it's not a crap shoot?
Thanks in advance for your help.
