98-99% iirc for a fixed (track) gear setup. There has also been a recent trend on the track towards larger chainrings and sprockets for a slight increase in ef

98-99% iirc for a fixed (track) gear setup. There has also been a recent trend on the track towards larger chainrings and sprockets for a slight increase in efficiency, as the chain has to go through less of a tight radius, whilst still maintaining the same gear ratio.