Identify the failure mode associated with 'wave mismatch' in crest-to-crest springs and its impact on bearing preload.

Wave mismatch occurs when the peaks of one turn do not align perfectly with the peaks of the adjacent turn. This is often caused by manufacturing inaccuracies in the pitch or by axial twisting during installation. When peaks are misaligned, the moment arm length changes, causing the spring rate to deviate from the design value. In bearing preload applications, this leads to non-uniform axial pressure on the bearing race. This non-uniformity causes localized heat generation, increased rolling resistance, and uneven wear on the balls/rollers, eventually leading to premature bearing fatigue (spalling) and system vibration.