According to the Vittoria app, given my weight, I should have my tyre pressure at 140. This is fine during the summer but maybe not so much with the winter coming in. I knocked it back to 120 this week. Feels a little more comfortable on the road, no frost or ice yet so I don't know if it sticks to the road better. Any point in lowering it further? Is there an optimum level for pressure in potentially icy conditions?