yup! it's a fact, less air will form more contact patch with the tarmac. but be careful, under inflation will induce uneven treadwear depending on size, shapes and angles of the tread pattern. I have had an unpleasant experience with Michelin Pilot Street Radial, front and rear.
uneven wear front & rear that caused steering vibration while cornering.
now on Pirelli angel gt with std 36/42 pressure, everything is silky smooth again. the best rubber I've got so far especially in the wet.
*lesson learned: for daily commuting, stick to recommended pressure.