>>1493813yall need smart cage to handle 34 tooth
or a rear derailleur with an SGS cage
RD-340 can handle between 11 and 34 teeth
and has a front chain wheel tooth difference of 20 teeth
so you could run 26 - 46
for freewheels normally 13 tooth is the smallest size
SunRace MFM4S Megadrive - 13-34T x7
or
Shimano Megarange MF-TZ31 - 14-34 x7