How They Shift
The key difference between SRAM and Shimano groupsets is the shifting actuation – the distance between shifts relative to the lever index.
Shimano’s 1:1 ratio means the cable and derailleur move further during each shift. For many riders this leads to a crisper shift, translating into better feel and allround robustness on muddy terrain and under load.
SRAM works on the tighter tolerance of a 2:1 ratio. Ideally, this means smoother shifts with less effort – although the downside is difficulty in gauging shifting feedback while riding, which can lead to unintended force under load.