Tomorrow I hope to ride for the first time in 6 months However, I sold my bike rack that I had bought for my mountain bike, so once again, I get to take the front wheel off my bike to put it into the back of my Kia Soul. That isn't a problem.

Because my inflated tires are wider than the brake calipers, I must deflate my tire to get the wheel off the bike. No problem, and periodically over the last 6 months I've inflated my tires and told my Gunnar how se*y a bike she is

A short time ago I was deflating the tire so I could remove the wheel. The tire was, basically, flat, and there was a POP. It sounded like it had suddenly gone flat but that makes no sense as it was already flat. Any thoughts on what might have happened? I am trying to avoid a trip to the LBS before riding tomorrow as, frankly, the purpose of tomorrow's ride is to see if I still get neurological symptoms on the bike. If so then I've a few choices to make.

Of course, it wouldn't cost that much to swing by the LBS tomorrow and have them switch out the tube...they can do that a LOT faster than I can. Is this a normal thing to happen when intentionally deflating a tire?