Quadriceps, Glutes, Lower Back, Upper Back
Calves, Chest, Forearms, Hamstrings, Shoulders, Traps, Triceps, Core
Squat before tire, chest against it.
Grip under tire tread.
Drive legs, lift tire edge up.
As tire reaches ~45 deg, drive knee into it.
Quickly switch grip to top.
Push tire forward to complete flip.
Repeat.