Originally Posted by
ebonho
1) Will a 11 speed chain work on the existing 8 speed crankset and chainrings.
no, it will not; the 11s chain is 5.6m wide so it will not fit on 8s cog designed for 7.1mm. Basically, the teeth are to thick to go into the chain gap.
this outer width affect the cassette shifting.
the chainring themselves are affected by the inner width; 2.18mm for 9 to 12 speed and 2.38 for 8 and below.
the chainring shift is controlled by the spacing on the crankset which is the same for 9 to 12 hence you can use whatever chainring and using 9/10/11 front derailleur. Some 11 and 12 may be narrower and rubbing but there is a trim trigger.
FYI, i was talking to the local bike shop about shimano groupset and the owner mentioned that he has been downgrading customer bikes from tiagra 2x10 to sora 2x9 with sunrace wide range cassette because it is cheaper, requires less maintenance and last longer.
https://bike.bikegremlin.com/1220/1-...compatibility/