Originally Posted by
lason
every time i go to ride my bike i find my front tire is flat. i've taken the tire off and there are no leaks in the tube and no punctures. i'll pump it back up and a few hours later it's flat again. the back tire is fine however. i keep my bike in my garage and it has been pretty cold lately so i wonder if that has something to do with it. i was hoping someone more knowledgable than me could provide some insight as to why this keeps happening.
You find no leaks or punctures. (I'll assume that you are checking under water) You did not say if you rode the bicycle before it went flat again. If you did, then a surprisingly common failure mode is failure to screw the nut back down on a presta valve. Normal riding will cause the valve to unseat (vibration etc) often enough to bleed air. Other than that, bad stem/valves cause as many slow leaks as holes in the tube.