These caps stick to my valve stems by themselves. The low tire light came on so I went to add some air but couldn't get the low tire loose. Then I tried others. Vain. I wish I had read the bad reviews about them before I bought them. They look amazing and I love them but if I had known that I could have saved myself a busy day. I'm lucky that I have a father-in-law who works as a mechanic and solved the problem for me. Not that I would keep the caps afterwards, but they didn't come out in one whole piece.