Originally Posted by
spock
Sure, that is exactly what I meant. Tube keeps the wheel true....
I believe you can make much better assumptions if you try.
It keeps nipples from turning because of the pressure that is applied by the tube on the nipple heads, or it makes it much less likely to unscrew as I had it happen on my double wall rim.
I think you're overestimating the friction between the nipple head and the rim strip, even under a fully inflated tire.
Both the friction of the spoke/nipple threads, and the friction between the rim's spoke hole and the nipple itself are far greater. If the nipple can overcome these frictions to loosen, a bit of top pressure from a rim strip isn't going to slow it significantly.