
Notable team and driver changes- Tom Sneva left Jerry O'Connell Racing for new team Bignotti-Cotter Racing. The team scaled back to part-time for 1981.
- Team Penske expanded to a three-car operation, with Bill Alsup joining. His owner-driver team Alsup Racing only ran part-time in 1981.
- After racing a limited schedule beforehand, Tony Bettenhausen Jr. ran his first full-time season with his new owner-driver team Bettenhausen Racing.
- Dick Simon replaced Sheldon Kinser at Leader Card Racing, leaving Kinser without a ride. Simon's old team, Vollstedt Enterprises, did not compete.
- Mario Andretti returned to running the majority of the races after a stint in Formula One, driving for Patrick Racing. He replaced Tom Bagley, who was left without a ride.
- Rookie driver Scott Brayton ran a full schedule with family-owned team Brayton Racing.
- After running part-time in 1980, Machinists Union Racing ran a full schedule with driver Larry Dickson.
- Spike Gehlhausen was replaced at Bob Fletcher Racing by rookie driver Bob Lazier.
- Josele Garza ran his first season with family-owned team Garza Racing.
- Steve Chassey ran his first full-time season for the Jet Engineering team.
- AMI Racing only ran two races in 1981 after running full-time in 1980. Gary Bettenhausen was left without a full-time ride.
- Interscope Racing also stopped running full-time, along with driver Danny Ongais.
- At Cannon Racing, Larry Cannon only ran the first few races, with most of the rest driven by Dick Ferguson.
- This was Bobby Unser's final season of IndyCar racing. See the 1981 Indianapolis 500 for more information.
Notable equipment changesScheduleOf note was the addition of the inaugural Michigan 500 to replace the California 500 at the now-closed Ontario Motor Speedway. The Tony Bettenhausen 200 at Milwaukee was originally scheduled for August 2, but was rained out and postponed until September 5.
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