>>1125597It's all about technique and nothing about brute force.
After getting the one side of the tire's bead over and onto the rim, and inserting the slightly-inflated tube (putting just enough air into the tube to give it a round shape also expands it's diameter a bit, making it easier to insert into the tire), start with getting the bead into the rim at the valve stem. With the wheel in your lap and the valve stem at the 12 O'clock position, working with your thumbs on both sides evenly (helps prevent the tube from moving, making the valve stem off-centered) push the bead onto the rim. When you get to the point where your thumbs are now at the 5 O'clock and 7 O'clock position, flip the wheel around on your lap so the valve stem is at the 6 O'clock position, and again with both thumbs keep working the bead over the rim and into the wheel. Occasionally run your thumbs down the sidewall of the tire towards the valve stem, pushing the bead of the tire already on the wheel towards the center; what this does is allow you to shift the whole tire upwards relative to the plane of the wheel, away from the 6 O'clock position of the valve stem, which gives you more room to work the bead of the tire the rest of the way over the rim. It takes a little practice and patience to learn how to do it this way the first few times, but if you do it right, you'll get the rest of the bead over the rim and onto the wheel without having to use levers or any other tool to force it.
This is the way I've been mounting tires for years. I only ever use tire levers when removing a tire, and then only because it's a little faster; it's possible (documentably so; you can google it) to also remove a tire without tire levers, it's just slower than using a lever.
