In this episode of Kilometre 0 we look at the way the transfer market works in professional cycling. Teams and riders can announce transfers from August 1 onwards but other negotiations can go on much later. On the eve of the Vuelta a España Richie Porte confirmed he'd be moving from BMC Racing to Trek-Segafredo. But what effect does the transfer window have on the teams as they try to compete in the final grand tour of the season. Kilometre 0 is supported by The Economist. UK-based listeners can get a free print copy of The Economist delivered to their door by texting **KM0** to 78070.