I need suggestions from experience or a table of compatibilities in order to find a compatible rear derailleur for folding bicycles (20" and 18" wheel)
I am aware that many the 28T max cog in the specs of many derailleurs is too conservative and they can works perfectly with 30 or 32T, specifically being 1x7 or 1x8 speeds
Notes:
I've already tested a Tourney RD-FT30(SS) with a link extender, a it reached the 34T but the derailleur position and tension was excessive.
Bike1 specs:
- Wheel 20"
- freewheel of 7 speed and 34T max sprocket,
- 1x7, shifter from "microSHIFT" brand (7v, index, comp. Shimano Mountain)
Bike2 specs:
- Wheel 18"
- freewheel (SHIMANO MF-TZ30-CP) of 6 speed and 34T max sprocket,
- 1x6 shifter from "sunrace" (6v, index)
Derailleur acronyms:
- SS: “Short Cage”
- GS: “Medium Cage”
- SGS: “Long Cage”