Originally Posted by Jipe

The Ti Birdy has a FSA SLK-light 52-36 and it folds+unfold OK. But honestly, I never tried to fold it on the 36t chainring mainly because I almost never use this chainring, the 9-32t cassette is enough for almost all cases.

And as already said, the TI Birdy has a totally different frame made to mount a double compact chainring (it has a front derailleur mounting soldered on the frame), nothing says that it has the same chainline as the Birdy 3 which is made for a single front chainring.

From factory, front and rear derailleur are Shimano 105 11s with a set of SL-RS700 2x11s shifters. I mounted the same right one on my Birdy 3 when I move it to 11s.