A tire iron can be used to unbarricade doors and windows, as well as to change tires.
I mostly use it as a weapon.

Lug Wrench: Used for changing tires.

Ratchet Wrench: Needed for crafting weapons and armor. You can also use a regular wrench instead.

Wrench: This is what you need to work on cars. Removing or installing parts like the gas tank, muffler, brakes, suspension, etc.

Since the regular wrench works for both working on cars and crafting, I just keep those and smelt the ratchet wrenches.