mysterious flat DS tire.

[MisterB]

Valve stem is a good place to start. It's happened a couple times to me with car tires (on cars) through the years.

[valkmc]

Yes on the valve stem. It happened to me once. Tire was down a couple of lbs one morning so I aired it up and went to work. Came out after work and it was flat. Luckily it was a Michelin Alpin Run flat. I drove it home 6 miles with zero air pressure. I replaced the valve stem with a metal one and the problem was solved.

[wildman]

I replaced the valve stem and so far problem solved. thank you for all your responses.