SLow leaking flat

runningvato said:

I think i should preface this by saying that i am relatively new to the sport of cycling. Anyways, i found that my tires were flat when i would go pick up my bike to ride. Somebody told me that this was a slow leaking flat and suggested changing rim tape. I did that (it ended up i had aero rim tape which was way too thin) and thought it would be the end of my problems. Then yesterday i was out and my tire just goes flat again. I can't see any puntures in it or anything of that nature. Any suggestions to as what could be the cause of my problem. I am not a heavy rider (150 lbs) and it's not like i abuse my bike by taking it down unpaved roads. I just find it very unusal to go through 8 tubes in a period of 3 weeks. There is nothing i hate more than having to stop to fix a flat. By the way, both the front and the back tires do this.

A couple of things I've run into over the years. One was a repeated little leak in a front tire that seemed to have no rhyme nor reason. I finally got under a really bright light and turned the tire inside out. I found a little baby sliver of glass that didn't quite penetrate the tire fully but obviously was enough when I occasionally hit something to cause a leak in the tube.

The second one was a crack in the valve stem of the tube that leaked only when it was flexed the "right" way.

Is the leak in the same place every time. If you mark the spot on the tire with a grease pencil where the valve stem is before you take the tire off, it's easier to double check the tire, I find.