Originally Posted by
Darth Lefty
Unless they've been patched! Then you get a stress riser around the reinforcement of the patch as the tube inflates to fill the tire, and eventually it will work itself apart. I found such a leak on my then-gf's bike.
Interesting! That hasn't happened to me yet, but MTB tubes in particular can look funny if you inflate them outside the tire after patching.
If the leak is gradual enough, I like to get some air into the tube while patching so it'll be closer to the inflated shape.