Tyler Hamilton is an American former professional road bicycle racer. He is the only American rider to win one of the five Monuments of cycling, taking Liège–Bastogne–Liège in 2003. Hamilton became a professional cyclist in 1995 with the US Postal Service cycling team. He was a teammate of Lance Armstrong during the 1999, 2000 and 2001 Tours de France, where Armstrong won the general classification. He was a key asset for Armstrong, being a very good climber as well as time-trialist. Hamilton appeared at the 2000 and 2004 Summer Olympics. In 2004, he won a gold medal at the individual time trial. The first doping test after his Olympic victory gave a positive result, but because the backup sample was frozen, no doping offence could be proven. After he failed further doping tests at the 2004 Vuelta a España, Hamilton was suspended for two years from the sport.