Originally Posted by Jeff Neese

Kenda has a line of cheap tubes labeled "Q-Tube". I bought four of them once and had two of them bad right out of the box. It wasn't the stem itself but the seam around the stem. I assume the Sunlite tubes that a lot of the local shops sell are the same. I stick with Continental and Schwalbe which I have to buy online. I've had good luck also with Specialized. There are plenty of good ones, but make no mistake - plenty of cheap ones that I won't trust any more. They are manufactured specifically to hit that sub-$5 dollar price point and you actually get what you pay for. They are not even individually inspected off the assembly line. They use "sampling" which means they pull out random samples, maybe one every ten thousand, and test it. They actually know that some defective tubes are slipping by. No thanks.

It might have been true in the past that "a tube is a tube" but not any more. Vast differences in quality.