Originally Posted by
BabyCowHK
Sorry I made a mistake of the total capacity of 28T on Saint/Zee Rd. It should be "25T".
Like I mentioned in the previous reply. Don't use Saint/Zee with a double chainring setup. The total capacity of 35T is too much for the super short RD cage to handle.
Front diff 53-39T=14. Rear diff 32-11T=21T. Total diff 14+21T=35T.
Consider going with R7000/R8000 short cage RD for 35T diff.
Shimano RD-R8000-SS short cage is limited to 30t for the cassette, it doesn't accept a 32t or 34t biggest cog while RD-R8000-GS goes up to 34t.
As said, a Shimano 53-39 crankset is a road crankset with a narrower chainline than the Birdy original crankset and might not work with a front derailleur (same as
the Dura-Ace 7800 of 50PlusCycling which doesn't work with a front derailleur). So, again, I advise to at least first try to mount a BCD130 53-39 on the original crankset.