With the Broncs trailing 8-6 early, Lindsey sparked a 15-4 run, scoring nine points as Rider took the lead and never trailed again.
The Broncs led at halftime 40-27.
Rider extended the lead with contributions from the other starters. Daniel Stewart and Anthony Myles scored 11 points each and Jonathan Thompson added 10. Junior Fortunat led the Broncs with nine rebounds.
Ahead 44-30, Rider used a 15-4 run with 10:25 to play to put the game away.
Rider shot 50.9 percent (27 of 53) for the game while Robert Morris struggled from the field, shooting just 25.5 percent (13 of 21) for the game.
Karvel Anderson led the Colonials in scoring with 11 points off the bench.