Although the development of asymmetric rim profiles is not a recent technology, the truth is that only now this innovation has been more widely applied. This is probably due to the increase in weight, concerning the asymmetrical rim, and to all logistics involved in rim drilling. In theory, the asymmetry of a rim is nothing more than the displacement of its holes, where the nipples that fix the spokes are inserted, at the opposite side of the hub cassette. In practice, it translates into the balance of the internal angles of the wheel spokes. Despite the weight handicap, this type of profile has numerous advantages:
Better stress triangulation/balance between both sides contributes to the durability of the assembly since the spokes will be less likely to get loose.
Increase the tension axial component at the Drive Side (DS), which helps to sustain the torque generated in the crank set and improves the lateral rigidity of the wheel.
Less propensity to rim breaks at the region of the holes since it will not be necessary to have such high stresses at the cassette side (DS).