Originally Posted by
rm -rf
Don't give up on your tires. The first flat was a broken valve, the second unknown--maybe a defective tube, it's hard to say.
You need to see the third tube when it's removed from the tire.
Where is the hole in the tube, and how big is the hole? How far is the hole from the valve--that will narrow down where to look on the tire and the rim.
If the hole is on the inside, toward the metal rim, maybe the rim strip that covers the spoke holes isn't covering every hole completely.
If the hole is a long split instead of a small hole, it wasn't installed correctly by the bike shop--the tire came off the rim and the tube popped.
Post more details about the tube and it's hole.
Post the numbers molded into the side of the tire. That will tell us the tire size.
the tire reads: (54-559) 26 x 2.0 40-65 P.S.I. (275-450 kPa) (2.75 - 4.5 BAR) on the side
the tube reads: 26 x 1.50 - 1.95
here is a photo of the burst tube:
http://imageshack.us/photo/my-images/813/bursttube.jpg/
The man at the bike shoppe kept the original tire's tube after he replaced the tube for me so I don't know what brand it was but it had a split valve which was halfway off of the tube.
The second man at the shoppe who repaired my bike's tire also kept the tube. He had taken my tire into the back of the shoppe when performing the repairs so I assume he just tossed it away. It only took him a couple of minutes to switch out the old tube and refill the tire with air. He didn't say what he thought had caused the damage to the tube. I looked inside the tire near the hole for the valve. There is rubbery rim tape inside and nothing scratchy. I don't think the rim tape could have slipped aside because it seemed very firmly in place and was hard for me to shift even to purposely look under it. There were some little nubs that looked like the top of screws which I assume must be the spoke ends people have mentioned. These were not directly over the burst area of the tube but were nearby (under the tape). Nothing felt sharp to my fingers. I wedged my fingers inside the tire to feel around and felt nothing sharp either. There is no hole or nail or anything in my tire either - no tire damage.