BMW set to introduce carbon wheels

Lighter is better. Less weight improves handling while increasing efficiency and performance, so even mainstream automakers are really beginning to push the boundaries of lightweight vehicle construction in order to meet emissions regulations and performance expectations.

When the BMW i3 electric city car launches it will be the first economy car sold in Australia to make extensive use of carbon-fibre and carbon-fibre reinforced plastic (CFRP). The i3 employs a carbon-fibre passenger cell – like an F1 car or McLaren 12C - while all of its body panels are made of CFRP, so despite lugging heavy batteries around it is very light.

Using lessons learned during the development of its new ‘i’ models, BMW is set to push the carbon-fibre envelope even further by introducing wheels made of the lightweight material. During BMW’s Innovation Days in Munich, the brand displayed two types of lightweight wheels; one featuring a carbon rim with alloy spokes which is around 25 percent lighter than an all-alloy equivalent. And one all-carbon design which is 35 percent lighter than an alloy.

Carbon wheels have previously been sold by aftermarket manufacturers in limited numbers at ridiculous prices, but BMW is the first automaker to develop them in-house. The German brand has indicated that these wheels are not planned for production or EU approval, however overseas reports suggest we could see the innovative lightweight wheels on BMW products within two years. 

The company is also finding uses for its secondary carbon-fibre – the scraps from i3 and i8 production. These offcuts are chopped up and mixed together with plastic molecules to create a material that will replace aluminium, magnesium and steel in semi-structural components like steering wheels, seat frames and even dash board support structures. And because this new material is made from what would normally be considered waste, it’s cheaper than magnesium and other lightweight metals.

BMW now just needs to prove to the regulators that these carbon components are strong enough and safe enough to be used on the road.