My shift pattern when I am trying to save gas, I try to keep the rpms at or below 2000 rpm. My best is 53mpg interstate exit to exit no breaks. Around town its usually in the mid to low 40's. However, if you are up 3 in the rear your mpg will drop drastically and you are probably getting worse than you think if your speedo is not corrected for the gearing. Just count your teeth to make sure what you have, a Gen 1 rear sprocket is 40 teeth and a Gen 2 is 42 teeth.