I know this will sound dumb but I'm really clueless. I have a mountain bike with tires that have lost pressure since it's been sitting unused for 7 months. I got a floor pump with pressure gauge and tried to inflate the tires but although the recommended pressure is 40-65 psi, I can't seem to pump them to that pressure. At around 25 psi the tires already felt very hard and the pump got really hard to push. I didn't want to push the pump too hard because I was worried the tires might explode. Should I pump more air no matter how hard the tires feel and just trust the pressure gauge?