Background & History of Carbon Wheels

carbon fiber

What is carbon fiber?

Carbon fiber originated in the aerospace industry. It is made of loose fibers composed of carbon atoms that are then suspended in resin to create a solid material. Carbon fibers or carbon fibres are fibers about 5 to 10 micrometers in diameter and composed mostly of carbon atoms. Carbon fibers have several advantages including high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion.

How is a carbon fiber wheel made?

Carbon fiber rims are made of two components; carbon fiber and epoxy resin. When molding a carbon fiber wheel, pieces of pre-preg carbon fiber are laid into molds. Pre-preg is raw carbon fiber that is impregnated with an epoxy resin. Prior to the invention of pre-preg, raw carbon fiber was laid in place and epoxy resin was applied over the carbon fiber, which was a messy and difficult process. Pre-preg makes for a much cleaner and workable manufacturing process.

Once the pre-preg carbon is laid in the mold, it is placed in an oven where it goes through a prescribed heating cycle know as a ramp cycle. The oven with the mold starts off at a low temperature, ramps up to a set point temperature and then lowers to an exit temperature. Each stage has a predetermined time. If you were to graph the temperature over time, a ramp shape is created, hence the name ramp cycle.

When the carbon fiber exits the mold, it is a hard finished part. However, all epoxy resins have what is called a “glass transition temperature” where the hardened epoxy turns from a glass back to a liquid. When this happens, the carbon fiber object becomes soft and will fail.

Epoxy resin design and selection is critical for carbon fiber rims. Today, epoxy resins have made major advancements and we can produce rims that handle high heat and are more durable than aluminum.

When was the first carbon fiber clincher made?

Lew Composites introduced the first full-carbon clincher rim in 1998. Company owner Paul Lew, an avid triathlete, wanted the same weight savings and aerodynamics that a carbon tubular could offer, but with the ease and versatility of a clincher.

When was the first carbon bike wheel used in a race?

In 1993, Heinz Obermayer and Rudolf Dierl develop a spoked wheel made of carbon, which immediately received UCI certification for pro-competition at its launch in 1994.

Post time: Nov-24-2022