Yeah that is what I think we are experiencing. If I am seeing 3/4 MPH difference at 35 MPH, then it would be more like 7 MPH difference cruising down the freeway at 70. That is quite the discrepancy! And a 10% difference would, over time, make the odometer quite inaccurate as well. At a 10% overstatement that would mean my Nissan bumper to bumper warranty expiring 3,600 miles too early??
This - buy 215/55 R16 when shopping for replacement tires. With 40psi inflation, expect almost 2% correction to the speedometer.It seems odd that the 205/55R16 was the chosen tire size instead of 205/60R16 or 215/55R16 - either would be within 1% of the diameter of the 215/50R17