Thank you Flash2001
You are right! Tread is important. I have been in contact with various engineers from tire companies (all for cars and trucks). There tread is used to pump water away. Unfortunately most commercial aircraft do not have treads except for the radial grooves.
I had a look at SAE, not really what I'm looking for and with prohibitive prices for their publications.
So - still looking for some light shed on the hydrodynamics under the tires...
