Just enough for shape. I let that little bit out because I had a heck of a time getting the tire on. It’s super tight on the rim. I tried to press the stem up by pressing through the tire. I even pulled the stem up with channel locks. It just won’t stay up.Did you have any air in the tube? If not you can pull it out and put just a bit of air in the tube that should push the stem through. Can't imagine that rim was made to use an extension.