Every time an innovative manufacturer comes up with a new use for carbon fiber composites, those of us in the industry are amazed yet again. There seems to be no end to how we can use things like carbon fiber plates, sandwich panels and tubing. We are apparently limited only by our own willingness to innovate (and oftentimes financial backing). Although not the first auto maker to build a composite wheel, Porsche is perhaps the most well-known company not afraid to push the boundaries of composite innovation.
Composites World magazine ran a story in early October describing Porsche's new high-performance wheel made from braided carbon fiber. The 20-inch 911 Turbo Carbon Wheel is now being manufactured exclusively for use on the 911 Turbo S as an OEM part. We imagine that if the wheel proves to be a hit with customers, Porsche will start manufacturing similar wheels for other models.
HOW THEY DO IT
We are used to things like carbon fiber tubing and door panels. A carbon fiber wheel is an entirely new animal. In fact, you might be asking yourself how it's possible to make a high-performance wheel using carbon fiber sheets.
Porsche utilizes a composite manufacturing process that has been around for quite a while. That process is braiding. Though there are different ways to deploy composite braiding, the manufacturing process used by Porsche creates carbon fiber panels that can then be cut and molded into different shapes.
A video included in the Composites World piece shows images of a rather large braiding wheel that, with a series of spindles, braids individual plies of carbon fiber tow into a long, continuous sheet of material that is soaked in resin and then pressed in a heated die. Being that the resin is heat-activated, it binds all the individual plies together as the material passes through. What comes out the other end is an incredibly strong yet lightweight material.
The large panels are cut into small pieces that are then used to create the composite wheel. Individual pieces are molded using heat and pressure, then layered to create the shape of the wheel. Finally, the wheel is put into another heated die where pressure and temperature work their magic. The finished wheel is both incredibly strong and surrealistically beautiful at the same time.
BETTER OVERALL PERFORMANCE
The obvious question here is why Porsche decided to create a new wheel out of carbon fiber panels. The answer to that question can be summed up in two words: better performance. If nothing else, Porsche is a brand known for high performance.
The company says that a set of four 911 Turbo Carbon Wheels is 20% lighter than their standard counterparts. Porsche says they are also 20% stronger. The increased strength-to-weight ratio allows tires to better grip the road and absorb both lateral and longitudinal forces.
Porsche says acceleration and braking are also improved with the new wheels thanks to a lower rotating mass. They say this significantly increases performance and, along with it, the pleasure that comes from driving a high-end Porsche. For now, the new wheels will only be available on the 911 Turbo S Exclusive as an extra option. They are not cheap, though. Composites World says a complete set in Europe runs in excess of €15,000 ($17,000).
Whether Porsche succeeds with their new carbon fiber wheels or not really depends on customers. If buyers believe the wheels increase performance and driving pleasure enough to warrant their high cost, Porsche will be more than happy to keep making them. Meanwhile, it's a sure bet they are looking for other ways to use carbon fiber panels to manufacture their world-class cars.