A 1000 mile trip, at 40 mpg, uses 25 gallons of fuel. the same trip at 42 mpg, uses 23.8 gallons. A whopping difference of 1.2 gallons, or about $3. Not a big deal for 1000 miles. Different fuel types and terrain will vary milage, as well as driving styles. But, none of us bought these bikes worrying about a couple mpg. Just ride and enjoy!