Dec 12, 2018 · Thus, a 110/90 tire is 110mm wide by 90 percent of 110mm tall. The math works out to 110mm wide by 99mm tall. For comparison, a 110/80 tire is 110mm wide by 88mm tall. More significantly, your 60/90-R17 tires are 0.47 inches (12 mm) larger in diameter than 60/80-R17 tires and the speedometer difference is 2.2%. Find Tires 21 in. Wheel Diameter, 80/90-21 Tire Size, Street Motorcycle Tire Type and get Free Shipping on Orders Over $109 at Summit Racing! 100/90-R17 tires are 1.42 inches (36 mm) larger in diameter than 80/90-R17 tires and the speedometer difference is 5.9% 130/90-R15 tires are 0.39 inches (10 mm) larger in diameter than 140/80-R15 tires and the speedometer difference is 1.6%. 80/80-R21 tires are 0.63 inches (16 mm) smaller in diameter than 80/90-R21 tires and the speedometer difference is 2.3% .

80 90 vs 90 80 tire