Also, the online application calculates the difference in real speed and speedometer readings if the difference between tire 225/45 R17 and tire 225/40 R18 is significant. Calculate the difference in inches. If you want to compare other tire sizes, then select their sizes in the drop-down fields and click on the green button. 225/45-R18 tires are 0.11 inches (2.9 mm) larger in diameter than 225/50-R17 tires and the speedometer difference is 0.4%. Aug 13, 2008 · 225 40 18 25.0866141732283 78.8118562204724 225/45 is closest to stock. Why not the Bridgstone 760's? [/quote] 235/40 is even closer at ~25.402" OD, so if he's planning on going with wider aftermarket wheels like he was thinking about, then that'd be the best choice for performance and looks. But with the stock rims, then yeah, 225/45 is 1st: 2012 Sport Auto Winter Sports Tyre Test (225/40 R18) 3rd: 2012 Auto Bild Performance Winter Tyre Test (225/45 R17) 2011 Tyre Tests; 1st: 2011 EVO Winter Tyre Test (225/45 R17) 1st: 2011 Auto Express Winter Tyre Test (225/45 R17) 4th: 2011 Winter Tyre Buying Guide (205/55 r16) 4th: 2011 Auto Bild Performance Winter Tyre Test (225/40 R18) Top 3 Avon ZV7 Reviews. Given 90% while driving a BMW 320D M Sport (225/40 R18) on a combination of roads for 2,000 spirited miles. Great dry grip in any direction! Wet grip is excellent when starting and stopping; they do slide a bit when pushed to the limits although you do have to push it very hard! Noise is a strong quality of Bridgestone Blizzak LM-005 - most dimensions have below average noise level values - 44% of them produce 0db noise, which result in "a" rating. This tyre has a initial tread depth of 8.2 mm in 195/55 R16. However, this can vary depending on the dimension (8 mm - 245/45 R19, 8.3 mm - 225/45 R17, 8.7 mm - 235/35 R19). .

225 45 r17 vs 225 40 r18