Asymmetrical Chainstays
Unbeknownst to most of us, when we torque on the pedals, not only are we propelling the bike forward, we're also pulling the rear wheel over to the drivetrain side of the bicycle. It is the one element of bike design that's not in perfect balance.
Asymmetrical stays help to stiffen the rear end. The drive-side stay is straight, while the non-drive takes advantage of no chain rings and chain, incorporating a better structure to improve rear end stiffness. By putting strength where it is needed, pedaling stiffness is greatly increased.