Rock star Mick Jagger previewed the Rolling Stones’ upcoming “Steel Wheels” album by playing a brief excerpt from the song “Mixed Emotions” during a press conference Tuesday at New York’s Grand Central Station. The conference, aired live on MTV and radio across the country, was called to announce the Stones’ North American stadium tour, which will commence Sept. 1 at Buffalo’s Rich Stadium. The tour, the first for the band since 1981, is expected to reach Los Angeles sometime in October, though only September dates have been confirmed so far. About 3 million people are expected to attend the tour, which will cover about 30 cities in the United States and Canada. Living Colour is scheduled to be the opening act on all dates.