gpvb1@comcast.net wrote:
........
>
> When I got home, I looked at the flat tire more closely. It appears that
> the valve separated from the tube, so it looks like the tire is a goner.
> But I don't know why it happened.
.....
This isn't all that unusual, either with tubulars or clinchers. I've had it happen to me several times. I just replaced a tube with that problem about a week ago. I suspect that it is related to the progressively lower quality of fabrication. You're lucky that you haven't experienced it earlier.
Steve Maas
Long Beach, CA