The RE40 was the first Renault chassis to be built entirely of carbon fibre. Construction of the chassis was outsourced to carbon fibre-specialists Hurel-Dubois, who had experience of the material through their aerospace background. The only part of the chassis not to be constructed in the new material was a small, aluminium nose section, known as the "crash box", that facilitated easy repair in the case of a minor accident. As Formula One use of carbon fibre was only a recent development, and following Didier Pironi's career-ending accident the previous year, the chassis was overbuilt to ensure strength.