What is the Weight and Dimensions of the Flywheel on the Diamondback Fitness 1260sr ? Dan October 01, 2020 22:26 Follow The Diameter of the Flywheel in the 1260ub Upright Bike is 265mm and it weighs 22lbs. Click to learn more about the Diamondback Fitness 1260sr Upright Bike! Related articles The Seat on My Diamondback Fitness 1260sc Slowly Lowers, How do I Fix it? Comments 0 comments Please sign in to leave a comment.