>>1858879a lot of 7 speed shifters have one more click, either by design, or because they're broken.
Some people say they get ok indexing between the two but in theory you shouldn't be able to. The key word is 'ok', possibly swap for 'not ok'.
The detents between shift positions are further apart than they would be on an 8 speed shifter. It's not a huge difference between 7 and 8, but over the whole cassette it will add up to 'meh' or bad indexing. Only the derailers are the same.
And for what advantage? The 11-28 silver shimano and 12-32 silver sram are good cassettes. Or run an old proper tight one.
I would much rather have perfect snappy shifting than slightly tighter gearing. And swapping your nice condition 105 out is also fully retarded.
