Tour De France: Simon Smart talks hi-tech cycling
16 July 2013 Last updated at 09:17 BST
The teams behind the world's fastest cyclists are obsessed with the small details that, when added up, separate the champions from the also-rans.
Simon Smart, founder of Smart Aero Technology, is renowned for his ultra-fast bikes, painstakingly tweaked for maximum performance.
The process is a complicated and sophisticated one, as he demonstrated to the BBC at the Smart Aero headquarters in Brackley, England.
Read More: The technology behind the Tour
Video journalist: Dave Lee