I find that although traction on icy tarmac is tremendously better with spikes than without, normal MTB tyres have more grip on dry tarmac. I tend to take it easy on tarmac, especially when leaning into a bend as the spikes seem to keep the rubber off the road surface a little (think hob nailed boots if you are old enough to remember them)as a matter of interest how is traction, wear, rolling resistance on non icy non snowy roads?
I'm not sure about wear on tarmac as I use mainly on tracks and haven't done enough mileage, just a few hundred miles, to see any significant wear yet. The centre spikes of mine are now either a little bit shorter or they have retreated a little into the rubber, the outer ones show no sign of wear at all.
Rolling resistance is noticeably higher on tarmac though no worse than normal MTB tyres on snow and ice.
They are of course as the name suggests, ice tyres and not snow tyres though they work as well as good knobblies on snow. I'm pretty heavy but find that 30 front 35 rear gives massive grip for off road and better rolling than higher pressure.
They do have disadvantages if it's not icy but if it's freezing I wouldn't go out unless they where fitted.
I have three bikes so it's ideal to have these on one of them, I'm fortunate (apart from being older than I want to be) in that I only cycle for pleasure and exercise so can pick and choose.
Dave.