What Pirelli's PNCS technology is and the noise reduction Pirelli reports for it.
Some Pirelli tyres carry a technology called PNCS aimed specifically at reducing the noise you hear inside the car. Here's what it actually is, based on Pirelli's own published information.
PNCS — Pirelli Noise Cancelling System — is a layer of sound-absorbing foam fitted to the inside of the tyre, against the inner liner. Its purpose is to dampen the resonance that builds up inside the tyre's air cavity as it rolls, which is a major source of the low-frequency "boom" some drivers notice inside the cabin at certain speeds.
According to Pirelli's own published information, PNCS reduces in-cabin noise by around 2–3 decibels on average, which Pirelli describes as roughly halving the perceived loudness of that cavity-resonance noise. This is Pirelli's own figure for their own technology — we're reporting it as their claim, not independently verifying it ourselves.
How much difference this makes in your specific car depends on more than the tyre — the vehicle's own insulation, wheel size, suspension and the road surface all play a part. A tyre with noise-reduction technology can still sound different from car to car.
