I've been having an annoying creaking noises that occur on the low part of left leg pedal stroke. The odd thing is the noise would disappear went standing and then start again within approx. 1 min of pedaling while sitting. I removed the FSA Gossamer left crank arm and cleaned spline area, removed rubberized metal washer then cleaned and added a little grease to it then re-assembled. No more creaking noises. I think the rubberized metal washer dried out combined with dirt/dust was generating this condition.