A rim is the outer edge of a wheel that holds the tyre in place on a vehicle. Steel rims, made from an alloy of iron and carbon, are more robust and resistant to damage than alloy rims. However, this durability comes at the cost of increased weight, which can lead to higher fuel consumption and slightly reduced performance compared to alloy wheels. Steel rims are ideally suited for rugged and heavy-duty vehicles due to their strength and ability to withstand heavy loads.