Hello everyone,

I'm a bit perplexed after having two flat tires in one day with no apparent reason (at least for the first flat).

I was about to leave for my daily commute to work and noticed that the front tire was flat after having ridden the bike from work the day before and having it sit overnight inside my apartment. After removing the inner tube and checking out the tire itself, I didn't find anything embedded in the tire itself so I changed the tube with a new one and left for work.

Leaving work, I noticed that the rear tire was deflated in which I pumped the tire up and rode it to a LBS where the mechanic checked the rear tire for debris and again found nothing. He then preceded to change the tube and unfortunately threw away the old one (I was too tired to think to ask him about the old tube and paid and left the shop).

Upon arriving home, I thoroughly checked the original front tube I changed in the morning by submersing it in water and could not find any puncture or air leak anywhere, and so far both new tubes haven't lost any air so I don't think either the mechanic or I missed something when we where checking the tires.

The only thing that I did previous to having both flats is washing the bicycle the previous day with dish washing soap and very low pressure from a garden hose.

Any ideas on what could cause at least one flat tire (or almost total loss of air from a seemingly good inner tube)?