Chargers strong safety Clinton Hart agreed to terms on a new five-year contract Monday that will keep him in lightning bolts through the 2012 season. ''We are very happy to have Clinton as a part of our future,'' Chargers General Manager A.J. Smith said. ''He was a first-year starter last year and was a major part of our team's success. We believe his best football is ahead of him.'' After spending three seasons as a key reserve and special teams player with the Chargers, Hart became a full-time starter for the first time in 2007. He started all 16 regular-season games and all three playoff games at strong safety. During the regular season, Hart was the club's third-leading tackler with 109 stops, trailing only Stephen Cooper and Matt Wilhelm. He also finished second on the team with five interceptions and tied for second with four tackles for loss.