Mine are quiet until 60mph, then they start to wail. The wear pattern is textbook perfect...had it checked twice. Maybe the strength of the steel and the machining process leads to a resonance ?? I really thought about having the gears polished before installation...but was afraid to mess up the "matching" of the ring to the pinion that is done at the factory. A few people may have a quiet setup, but the majority will have some noise.