If you are having tyre noise problems, are they less in wet or damp conditions? I can't see how that could be, unless there's some 'scrubbing' action involved in creating the noise? If so I would expect a wet or damp surface would serve as lubrication, lessening the noise. I can't really see how damp/wet conditions would lessen noise transmission due to basic tyre construction, suspension transmission routes or lack of sound proofing.

I would go along with your logic, as the water could serve as an acoustic barrier/cushion of sorts, between the tyre and road surface. I would expect any issue to be most noticeable on a bone dry road surface.

Steve

A thing I had been told by a friend of mine was about tyre consumption in the wet. He told me that in the wet, tyres get more consumption as they struggle to get traction (at speed, of course), so they actually "scrub" more than when having good contact with the road. If this is the case, I get the more scrubbing would generate more noise, too. What do you think about this?

Anyway, with my Octy on highway, in the wet I would say I perceive more noise.

Its well known that tyres generate considerably less noise on a moist road surface. Microscopically, the tyre and road surface are covered in asperities (tiny peaks and troughs in the material). As the tyre rotates these slam together (numerous small impacts). A layer of moisture cushions the impacts and so less noise is generated.

Oviously on a very wet road noise can arise from other sources (water spay hitting the underside of the car).

Perhaps I should have better specified I was referring to when it rains consistently.

Tyres are designed to 'pump' water away when driving in heavy rain/standing water. Obviously this requires a certain energy input so fuel consumption can increase. When driving on a very wet road you can actually feel the additional workload on the car. There are other factors to consider too - on a very wet road if you drive too fast then the tyre cannot pump the water away quickly enough and the tyre starts to aquaplane....