It is measured in millimeters (mm). The number after the / is the height of your tires. So, in our example the tire height would be 35. Shop 17 inch tires by tire width and height to find the perfect tires to fit your car, truck or SUV. Call (844) 338-0739 to get a quote & schedule an installation, or visit us online today! 240/50-R18 tires are 3.09 inches (78.4 mm) larger in diameter than 170/55-R17 tires and the speedometer difference is 11.2% 170/50-R19 tires are 1.33 inches (33.8 mm) larger in diameter than 170/55-R17 tires and the speedometer difference is 5.2% 180/50-R17 tires are 0.71 inches (18 mm) smaller in diameter than 180/55-R17 tires and the speedometer difference is 2.8%. 180/55-R17 tires are 0.91 inches (23.2 mm) smaller in diameter than 170/80-R15 tires and the speedometer difference is 3.6% Bike is GSXR600. Biggest change was slower turn in. I felt like I was running wide in a lot of turns. Lowering the triple clamps on the forks by 4mm solved this. My tire guy claims the 190 is good for a more aggressive corner "attack" style. Think Marquez. And the 180 is better at smooth Lorenzo style riding. The Dunlop D407 and D408 are designed in cooperation with Harley Davidson. With a more modern dry weather look than other options from Dunlop these work a treat on a sunny day. Our Price £ 203. was £ 224. Tyre Size. Quantity. — OR —. Add to basket. Make 3 payments of £67.66. In the tire comparison table above, you can see a detailed calculation of the size difference between 235/55 R17 and 225/65 R17 tire. The calculation results are presented in the form of visual infographics, on which tire with size 235/55 R17 is on top, and tire with size 225/65 R17 below. Both in the table and in the graph, the tires are 225/45-R17 tires are 0.61 inches (15.5 mm) larger in diameter than 170/55-R17 tires and the speedometer difference is 2.4% Pirelli Diablo Supercorsa V2 Front 120/70ZR17 & Rear 180/55ZR17 Road & Racetrack Motorcycle Tires w/Keychain - 120/70-17 180/55-17 Two Pack 3.8 out of 5 stars 11 $359.96 $ 359 . 96 C9U7M.