I've had a Marathon Winter tyre on the front of the commuter for the last week, as I had a puncture in the other wheel, so as I couldn't be bothered to change the inner, I put on the spare wheel with the winter tyre. Today I fitted the rear one, and put on new front brakes, and went for a little ride in the snow.
I really need some sort of magic tyres you can instantly raise or lower the pressure, as you need around 35 psi to reduce the slippy effect on icy ridges of snow due to car tyre tracks, but then as soon as you get onto clear main roads, you need 85 psi or it's really hard work.