Tyres for Mazda 3 Neo

Road noise from the rear is a problem many Mazda3 owners have complained about right from the launch of the car and there’s not a lot you can do. Fitting different tyres is the first thing that most people do, and like you have found, they make little if any difference. I would suggest you could try applying some noise deadening material to the panels inside the car, particularly in the rear, which seems to be the main noise generation area.