Report: Carbon Fiber Needs Improvements to Replace Aluminum
August 7, 2018—Carbon fiber that is lighter yet stronger than aluminum still needs improvements in mechanical property and scalability before becoming a replacement metal to aluminum for bicycles, according to industry sources quoted in S&P Global. As a result, changes in Japan's massive bicycle sector will have implications for the larger four-wheeled passenger vehicles.
"Japanese aluminum diecasters are evolving. Bicycle components makers went from commodity-grade alloy to high-strength proprietary alloy and now they are coping with carbon fiber," said one Tokyo-based trader of aluminum-silicon-magnesium alloy products.
Other aluminum alloys used include ADC12 used for 1 kg-motor box of electric bicycles. This component however, is still made of aluminum, one diecaster said.
The substitution accelerated around five years ago with the advent of a technology to control the fiber strength and shape during the fiber weaving process, said an official from The Japan Bicycle Promotion Institute.
"This technique reduced production cost and along came scalability, and the spread of its application, as carbon fiber composite shapes could be more flexible," an official with The Japan Bicycle Promotion Institute said.
Usage is still slow for bicycles, as carbon fiber is not able to absorb shock as efficiently as metal, the official added. When impacted by collision, the material breaks apart into pieces while aluminum dents.
One aluminum rolling mill official estimated it would take 10 years for carbon fiber collision resistance to improve before being able to be a replacement, while one automotive supplier source said five years.
"Carbon fiber replacement of aluminum pipe in the main structure started around five years ago with Tour de France-type of road race bike models. Lightweight was vital for faster pedaling," he said. Around 10 kg of carbon was used for one bike model, the official estimated.
Long production process is one of the reasons for the carbon material to be costly, and process improvements are needed to achieve scalability, industry sources said.
Toyota Motor uses carbon fiber for the fuel cell stack of hydrogen fuel cell vehicle Mirai.
Toyota sold 1,070 units of Mirai in the first half of 2018, a decline of 8 percent year on year, and marginal compared with Toyota's monthly total domestic sales of 100,000 vehicles.