Every tire is going to experience some form of resistance, both from the road and the air rushing past it. This accounts for some of the low hum you will hear while driving, but tires are also hollow belts of rubber constantly bouncing off a concrete surface. This means they will be constantly vibrating from the constant impacts and these vibrations will also create lots of noise. While you can design the tread to reduce noise as much as possible, you can never get rid of it entirely. This is because tires still need to perform their primary function of gripping the road in any weather conditions. This grip will always create friction and that friction will always create some level of noise.