Ok, I have a dumb question.

Some wheels it looks like the tire is narrower than the rim, and so the rim seems to be the part the sticks out the most. Other wheels look like the rim is deep inside the tire, like the tire is too wide for the rim. And of course, there's those that look just right.

What's the deal with this?

I'm going to have to pick new tires and I want to make sure it's "just right" for me. Is this a difference of picking tire sizes, or the model of tires?