Roller replacement
Hello,
Thanks for reaching out! I'm sorry to say the roller cannot be replaced. Unfortunately, it isn't sold separately. If you are experiencing issues with it, you'll need to replace the entire operator.
From what I can see in the photos, I believe you'll need the 39-031 EntryGard Dual Arm Operator. To confirm, carefully review and compare the dimensions. There are a few tutorials, tagged below this thread, with instructions on how to remove/install them.
The opposite version of this operator can also be found tagged below, along with the compatible hardware and accessories.