I have been busy this past week and haven't been able to ride, so my bike has been sitting in the back of my car hopefully not collecting dust. The last time I rode I forgot to put the valve cap back on, and lost it when I went riding. I went today to go ride, and found that the tire with the missing valve cap was completely flat. I thought that the only way a Shrader Valve could let out air was if you depressed the button in it? Is this not the case?
Also, I did not check to see if there was a puncture to the tube yet, so that may be a possibility as well. Really, I was just wondering if it was critical that the valve cap be left on.