Stages Power R and Stages Power LR power meters built onto Shimano Ultegra R8000 and Shimano Dura-Ace R9100 drive-sides are tested to be compatible with only R8000 and R9100 chainrings in 53/39, 52/56, and 50/34 size combinations. While it is possible that some other offerings and sizes may fit, we cannot guarantee the fit or compatibility with other size combinations and third party offerings at this time.