NEW YORK -- Tyler Hamilton says writing his tell-all book about Lance Armstrong felt like taking "a thousand-pound backpack" off his shoulders.
Hamilton tells The Associated Press he always thought he'd take some of the secrets about doping and cycling to the grave with him.
But he says his world changed when he received a subpoena to testify to a grand jury looking into the Armstrong case.
The 41-year-old Hamilton, who rode with Armstrong on the U.S. Postal Service team from 1998 to 2001, details the years he spent lying about using performance-enhancing drugs and his relationship with Armstrong in his book, "The Secret Race, Inside the Hidden World of the Tour de France: Doping, Cover-Ups and Winning at All Costs."
The book was released Wednesday.