Mr. Coyle 's notion was to follow Armstrong as he prepared for last year 's Tour , and to get to know his trainers , closest supporters and teammates -LRB- for years he rode for , and controlled , a team financially supported by the United States Postal Service , whose sponsorship has now been taken over by the Discovery Channel -RRB- , as well as rivals like Germany 's Jan Ullrich , the Basque Iban Mayo and Tyler Hamilton , a fellow American .