Are different 11 speed cassettes made for different situations? Example; is there a cassette better suited for hills, vs. flat land? This morning I was on the big chain ring up front, and on the number 5 from right on the back. I was cranking at about 105 rpm and decided to shift up, but it was a huge difference. My rpm dropped dramatically to 85 and I could really feel it in my legs. This old timer I ride with, swears I am missing the 18 tooth cassette, and that’s what I need for flat ground.