The Broncs' 46 points were the fewest the Greyhounds have allowed since defeating Niagara 68-45 on Feb. 21, 1992.
Loyola (17-5, 10-2 Metro Atlantic Athletic Conference), which has won five straight games and eight of its last nine, also snapped Rider's three-game winning streak.
The Broncs (9-15, 6-6), who averaged 87.3 points in their previous three games, posted their lowest point total since losing 65-40 to Fairfield in the 2003-04 season.
Leading 6-5, the Greyhounds went on a 29-4 run. Loyola held Rider to 3 of 23 first-half field goals while forcing 12 turnovers to lead 39-12 at the break.
Daniel Stewart led Rider with 13 points and 10 boards.