205/45-R17 tires are 0.81 inches (20.5 mm) larger in diameter than 205/40-R17 tires and the speedometer difference is 3.3%.
If you do a 235 vs 245 tire width comparison, the 245 tire is wider than the 235 tires. For 235 tires the width is 9.25 inches whereas it’s 9.65 inches for 245 tires. Again, if you consider the height, the 235 tires are 4.56 inches whereas the 245 tires have a sidewall height of 4.8 inches. However, both of the tires will fit rims with a5869. Better Fuel Economy Factory Ratios Increased Power. 245/45-R18 tires are 0.96 inches (24.5 mm) larger in diameter than 245/40-R18 tires and the speedometer difference is 3.6%.
In the tire comparison table above, you can see a detailed calculation of the size difference between 225/45 R17 and 245/45 R17 tire. The calculation results are presented in the form of visual infographics, on which tire with size 225/45 R17 is on top, and tire with size 245/45 R17 below. Both in the table and in the graph, the tires are 295/35-R18 tires are 1.16 inches (29.5 mm) smaller in diameter than 295/40-R18 tires and the speedometer difference is 4.3%.