The initial sessions for Western Sides began in early 2004 after the last No City Fun shows and AM's appearance at South by Southwest in March of 2003. As with Late (1997) and No City Fun (2003), David took the helm for the Western Sides sessions at the Tempermill. Detroit drummer Charlie Koltak. who the band had long been a fan of, played drums on the sessions.

American Mars continued to play and record throughout 2004 and a 2005 release for the record seemed like a realizable goal. In March of 2005, however, bassist Garth Girard delivered the news that he had been diagnosed with cancer and with that all AM business came to a halt. Garth had successful surgery that April and began radiation and chemo later that spring. During that time David and Thomas put Team Mars together as a way of supporting Garth and his family. In reality, Team Mars was really just a way for the band to keep friends and fans up to date on Garth’s progress but it also gave them the idea for a team-relay fundraiser in Detroit’s annual marathon.

Garth was given a clean bill of health in early 2006 and AM started playing and recording again throughout that spring and summer. In early Fall, they convened at the Tempermill to record the album’s final tracks, “Better Angels” and “Make It Up” and then left David to pull together the final mixes. The record was mastered in January of 2007 by Sir Dewey Stern in Lancashire, England.