GREEN AND DISAPPOINTED: Low Rolling Resistance Tires Don’t Meet Consumer Expectations. This seems a function of expectations, mostly. They do make a difference, though. Back when I was still driving the Passat wagon I switched from the Michelin Energy low-rolling resistance tires to the higher-rated XGTs and the difference was noticeable. (One indicator — when the car was in neutral in my driveway, it would roll backwards with the Energy tires, but stayed put with the XGTs). It was about a 1 mpg difference as far as I could tell.