Bicycle Aluminium Rim Plant are built with a blend of aluminum and nickel. The majority of wheels today are cast aluminum , meaning they’re made by pouring molten aluminum into a mold. They are lightweight but strong, withstand heat well and are generally more attractive than steel wheels. They come in a very wide variety of finishes and sizes. Aluminum wheels are a good choice for a balance of performance, cost, aesthetics, and gas mileage.