A good reason to ride fast on a commute
 

This morning as I was putting air in my front tire I noticed a half-inch slash across the casing that was bulging slightly. Foolishly, I decided to push my luck and hope it would make it through the day. About a mile and a half from work, the magnet on the front wheel started hitting the computer sensor, so I stopped and leaned down to fix it. As I did this, I heard the subtle hiss of air leaving my tire -- just a little but there was no doubt it was happening. At this point the tire still had pretty decent pressure, so I figured if I really hauled I might make it to work before it was too flat to ride. Surprisingly, it worked!

It was still leaking audibly when I got to the office. I brought the wheel in to fix it in the comfort of my cubicle but waited to see how long it would take to go flat. As it turns out, it stopped leaking (or more likely just slowed down a lot) at around 30 psi after about 10 minutes.

I guess it's time for a new tire.

You must have the world's most sensitive human ears if you can hear a leak through a tire that was so small that it took 10+ minutes to deflate to 30psi.;)

The tire was wet and the casing was open at the point of the leak. It was easy to hear.