Gauge doesn't seem to be working on Joe Blow floor pump
I'm a newbie so maybe it's just me. I bought a JoeBlow Sport Floor Pump off Nashbar. I've never had a bike before so I've never had to inflate bike tires. Well I've been riding for a week now on my new bicycle and decided that I should check the pressure. The recommended pressure is 60 - 80 PSI for my 700x35 tires (on a hybrid bike). The gauge doesn't seem to be registering. The needle goes up when I stroke some air in but then drops back down to around 0 (the gauge is in the locked position with no air coming out). After tinkering for a while (and letting a bunch of air out) I finally got a reading but it only got up to about 30-35 psi on the gauge when it wouldn't inflate any more without a struggle. Using my thumb it felt like it was good and full, but then again I don't have much experience. Do I need to calibrate the gauge or something? Also, what pressure should I inflate too? I'm just doing commuting along a bike path (13 miles roundtrip).