Hi guys, my car's stock tyre size is 215/65/R16 but my family member changed it to 215/60/R16 a few years back. Based on Miata.net's car tyre calculator, there is a -3.21% difference in diameter, way above the recommended +/-2.5%. Apart from an inaccurate speedometer and mileage, what other parts could have been affected due to this tyre size difference? Also, I saw from the sidewall that the tyre was manufactured in the 40th week of 2010. Is it about time to change the tyres, although the car hasn't been driven much? I kinda want to go back to the stock sizing and was wondering if anyone has recommendations. Thanks all!