Got a new tire put on my rim and I went to use the bike and the tire is flat. I filled it up with 30 pounds but the next day it was 26 and a few days later it was flat. Is this a bad valve stem? Bad bead? or the rim? I just bought the bike and put new tires on it and was told they are fine. The bike was only moved from my garage to my trailer to the paddock at the track so I don't think there's anything in my tire.
Either that or you pick up a big fat nail... Maybe the rubber is separating allowing air to seep through it's molecules...