Career
He jointly holds the record for the most wins in a season with Mat Mladin. In 1988 the Superbike World Championship began, with Merkel entered on the RC30. He took three more wins en route to sixth overall in 1990, but was less competitive after this.
Merkel retired from racing at the end of the 1995 season after being injured in an accident at Firebird International Raceway in Chandler, Arizona.
Merkel and his family moved to a ranch they owned in New Zealand. He was inducted into the American Medical Association Motorcycle Hall of Fame in 2001.