Higher pressures DEFINTELY will earn you more MPG. But it's a decision which might cause you a lot of trouble to make. Read on this forum and the web for all the varying opinions....User xcel on this site swears by the safety and MPG benefits of over-inflating, so he might be able to refer you to other posts he has made on this issue - he is a MPG champ, so his tips DO INDEED work. I have settled on 48-50 PSI for the stock Bridgestone B381 on my 2004 HCH, and I have averaged about 48.3 MPG so far..Good luck...