Difference Between a Forged & Cast Aluminum Rim
- Gravity casting involves pouring molten aluminum alloy into a wheel form and allowing gravity to do the work of filling the cast. This process is cost effective but creates the lowest grade of aluminum wheels available on the market. While still stylish and fully functional, wheels made by gravity casting are heavy and not nearly as strong as wheels made through other processes.
- Low pressure casting is a step up in quality from gravity casting. In this process, molten aluminum alloy is pulled up into the cast by a vacuum. This removes air from the alloy that is left behind by gravity casting, creating a denser product. The denser the aluminum, the lighter the weight and the stronger the product. Low pressure cast wheels are highly desirable for those looking for a quality product at a reasonable price.
- Unlike the casting processes, the aluminum alloy used in forging is not molten or poured. The aluminum alloy is softened, creating what is called a "billet." The billet is then forced between two dies under enormous pressure. This forces out all air pockets and leaves a product that is dense, lightweight and much stronger than any cast wheel. The price of forged aluminum wheels reflects their quality and desirability.
- In most cases the more dense a product, the more it weighs. But with wheels, the denser the aluminum, the less product is required to produce the wheel. A lower volume of aluminum equals a lighter-weight wheel. Lighter-weight wheels improve gas mileage and the car's overall performance.
- Gravity cast aluminum wheels are fine if you don't drive your car often. They are inexpensive and will hold up for a long time under light use. For the vast majority of cars and trucks on the road, low pressure wheels will do the job. High performance vehicles and those used heavily will benefit from forged aluminum wheels. Although they are more expensive, they will draw the best performance from any vehicle.
Gravity Casting
Low Pressure Casting
Forged Aluminum Wheels
Denser but Lighter?
Choosing the Right Wheel
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