Thanx for the advice!
Sadly the larger tyres are mostly, like the ones used in Iceland, used in fresh snow or powder.
Driving on roads with a closed ice cover as it´s pretty common in Norway or Finnland is a completely different story. Sady most people in these regions don´t seem to drive 315/75s.
As studs are not road legal in most of Europe I need a set to get up north and back home again and a studded set which I´ll mount when getting of the ferry in Sweden.
I have often seen images of LTs in Alaska with pretty large tyres, but have no idea of what´s a common winter tyre up there.