Because it only has to drive in one direction? I know they have had some issues with 7900 chains and recommend 7800, so it seems that they have left some material on the driving side of the tooth profile to reduce roller pressure which puts their chainrings at the margin of what's acceptable to avoid chain suck
Because it only has to drive in one direction? I know they have had some issues with 7900 chains and recommend 7800, so it seems that they have left some material on the driving side of the tooth profile to reduce roller pressure which puts their chainrings at the margin of what's acceptable to avoid chain suck