My bead breaker is all metal. Since you're using it only on the tire it shouldn't be a problem. I use carpet and wood blocks for the wheel to rest on to avoid messing up the rotor or other side of the wheel.
Dragging knee is for the track, and dragging tail is for the lot. --Kane Friesen
When you're in a car, you're watching a movie; when you're on a bike, you're in the movie. --Robert Pirsig
Identity theft is not Fun