130/90-R18 tires are 1.02 inches (26 mm) larger in diameter than 130/80-R18 tires and the speedometer difference is 3.8%.
120/80-R19 tires are 0.24 inches (6 mm) smaller in diameter than 110/90-R19 tires and the speedometer difference is 0.9%. 120/90-R17 tires are 0.31 inches (8 mm) larger in diameter than 130/80-R17 tires and the speedometer difference is 1.2%. tGZZ0r.