Hamilton suffered a broken collarbone in the accident.

"We're supposed to be preparing for [the] tour right now," the singer wrote in a message posted at Helmet's website. "Unfortunately we had to push things back after I hit a tree up in the mountains of Oregon and went over the handlebars of my bike. I had surgery in LA. They sawed off part of the bone near my shoulder and tied it together with a cadaver tendon and 3 screws; I expect to recover completely and the tour ... will proceed as planned."

Hamilton's injury has also led to the delayed release of "Size Matters," Helmet's first collection of new material since 1997's "Aftertaste." The set, which originally was due out on Tuesday (9/14), is now slated for release on Oct. 5.

Helmet's revamped lineup features founding member/frontman Page Hamilton, along with guitarist Chris Traynor (Orange 9mm), drummer John Tempesta (White Zombie) and bassist Frank Bello (Anthrax). Absent from the mix are any of the band members who played with Hamilton on the group's previous albums.

Hamilton produced "Size Matters" with assistance from producer Jay Baumgardner and multi-instrumentalist Charlie Clauser (Nine Inch Nails). The album features the single "See You Dead."

Helmet rose to fame on the strength of its full-length debut, 1992's "Meantime." The set spawned the singles "Give It," "In the Meantime" and "Unsung." The group also scored hits with the soundtrack cuts "Just Another Victim"--a song from the 1993 film "Judgment Night" that paired the group with hip-hop act House of Pain--and "Milquetoast," from 1994's "The Crow."