As I wrote and as showed on the Sheldon Brown website, the chainline is the distance between the center of the bike and the chainring.




It doesn't change when you increase or decrease the chainring.

Most Birdy are factory equipped with a 52t chainring and the Birdy Touring has a 9-32 cassette.

I have a 52-39t front and -32 rear and there is space for more. I took 9-32 because my rear derailleur (Shimano Ultegra now) is limited to 32t rear.

The cassettes I have shown are all road cassettes including the 9-34 and 9-36, they fit on my rear wheel as my 9-32.

The Shimano XT M8000 11s is a kind of alien that was made to allow to move to 11s with 9-10s rear hub.

Shimano now moved to microspline with also cassettes starting at 10t.