Oval rings are an age old idea. There must be a reason they keep failing in the marketplace, get reintroduced as new and improved and fail again. Failure is not bad in this case, it simply demonstrates market demand was not enough to sustain the idea. Biopace came on two of my mountain bikes back in the 80's and after experiencing knee issues with them, they were replaced with round rings, which leads me to believe each user reacts to them differently, which goes to demonstrate that no one thing is the right thing for all users. Glad you like them!