I have a pump (harbor frieght special-but it works just fine) . I will check both tires after work. So, are you saying 39 front/42 rear. That's what I'm keeping it at. I wonder if the setting, one rider, is firing this off. I weigh 260 and I carry a pretty good amount of gear with me(tools, rain gear, and other things). Maybe I should set it at one with luggage, or two riders? Sound silly I know and I realize there is probably no relation. I guess I'm puling at straws because I don't want to take it in for service. Oh, I love this bike:)