Olympic gold medallist Wiggins has local knowledge of the route, which stretched from Carlisle to Blackpool
"Bradley lives not far from Blackpool and the route included a lot of the roads he uses for training," Cavendish told BBC Sport.
"He told us it was very open, and very windy, and he knew the exact place we should go on the attack. It was the perfect call."
Cavendish is now the overall leader of the Tour.