I keep having a problem with flats on my front wheel. The valve stem gets a tear right at the base where it joins the tube. The first time I just replaced it and didn't look too carefully. The second time I got suspicious and checked out the hole in the rim and it had some sharp edges. I tried filing and smoothing it out, but the same thing happened a third time. At that point I tried getting these aluminum tube shaped things (prest savers)to line the hole and run presta instead or schraeder. Well....then the presta tube went flat with the exact same tear. Now I noticed that the hole in the rim tape is not centered properly, so I straightened it out. Do you think that was the problem all along. I'm feeling pretty boneheaded right about now.