The term "steel wheels" refers to a type of wheel that is made entirely out of steel. These types of wheels are commonly used on heavy-duty vehicles such as trucks, buses and construction equipment due to their strength and durability. Steel wheels can also be found on some older model cars, although alloy or composite wheels have become more popular in recent years. The term "steel wheel" is often used metaphorically to describe someone who is tough, resilient, and determined, much like the material from which their namesake wheels are made.