From Wikipedia, the free encyclopedia. Nathan Rennie (born 31 May 1981) is an Australian professional downhill mountain bike racer. He started riding at the age of 5. In 2008, he became national champion downhill. He won a bronze medal in the downhill category at the UCI Mountain Bike & Trials World Championships in 2006. In the UCI Mountain Bike World Cup, Rennie won the downhill category overall in 2003 and came