After my OEM Bridgestone Ecopias E20, I replaced with the Michelins hoping for a bit better MPG. Bridgestones averaged 53.9 for the last 20,000 miles. The Michelins are at 46.6 for the first 7000 miles. I am very disappointed in the MPG decrease.The best I have acheived on my daily commute of 88 miles has been 47.9. I would not recommend these on the Prius based on mypersonal experience. They are terible in snow or ice.