Originally Posted by Jipe

About the Sunrace hub and cassette mounted on the Birdy Touring: I never experienced problem with it, it shifts very well with a Shimano derailleur and it has been realiable for me.

But, its a proprietary solution, the hub accepts only the Sunrace special cassette and this cassette can only be mounted on a Sunrace hub (and maybe the now discontinued Shimano Capreo that R&M was using before the Sunrace solution). These Sunrace components are pretty difficult to buy if not from a R&M dealer (that must most of the time order it).

On my Ti Birdy, Pacific Cycles mounted a standard Shimano rear hub with a 11s 11-28t cassette (both Shimano 105), the range is quite short and the longest ratio too short (front chainring is a FSA SLK-light compact 52-36).

I therefore looked for another solution and moved to a new rear wheel with an XDR body rear hub and Ethirteen made 11s 9-32t cassette (the previous generation Shimano Ultegra RD-R6800 derailleur I have is limited to 32t max).

When the cassette of my Birdy Touring had to be replaced, I did the same on my Birdy Touring that has now an 11s 9-34t Ethirteen cassette and Shimano Ultegra RD-R8000 derailleur. I hesitated between this solution and a SRAM Force Etap AXS 12s and 10-36 cassette but since it is a daily used utility bike, I preferred a mechanical rear derailleur.