Frank Otis added 12 points for the Wildcats (13-3, 8-0 Big Sky), who have beaten Sacramento State 11 straight times.
Sacramento State was within 56-54 after Garrity hit a jumper with 3:21 remaining, but Weber State scored nine straight points on a basket by Tresnak, a 3-pointer by Jordan Richardson, two free throws from Bamforth and a layup by Otis.
The win sets up a big week for the Wildcats, who face Montana State (3-4 Big Sky) on Thursday before squaring off with Montana (8-0) in a battle for first place next Saturday.
Michigan has hired assistant basketball coaches Billy Donlon and Saddi Washington.
Duke and Cincinnati, 2016 NCAA tournament teams, highlight the eight-team field for the Naismith Memorial Basketball Hall of Fame Tip-Off Tournament.
NCAA champion Villanova will play Notre Dame and Pittsburgh will play Penn State in the inaugural Never Forget Tribute Classic at Prudential Center on Dec. 10.