Part of Wilco's identity at the time that A.M. was released was defined by the instrumentation they used, which led to their classification of "alt-country." They quickly outgrew this title—even by their second album, Being There—, but on A.M. it seemed to fit. This is because of the dry, organic studio treatment of the drums, the presence of both acoustic and clean electric guitars, the somewhat tuneless crackle and subtle twang of Tweedy's singing, and, of course, the presence of the banjo and fiddle on almost every song.
On "Passenger Side," a mandolin, played by Max Johnston, who also provides the fiddle part, replaces the banjo. Sandwiching the fat acoustic strumming, the mandolin serves as a plucky counterpart to the jangly electric guitar part, which, though not a twelve-string guitar, is still reminiscent of the folk-rock tendencies of groups like The Byrds. The fiddle part weaves in and out of the foreground, keeping the rhythm fluid and continuous despite the slow punch of the rhythm section. Ken Coomer plays the drums just behind the beat, so it sounds like the song is constantly trying to catch up with itself. In addition to creating a rootsy and organic musical texture, these techniques also work to complement the lyrics, creating a slow and late-to-react progression that somewhat recalls the movements of an inebriated person stumbling and swaying in the early hours of the morning after a night of heavy drinking.