Riding 20 miles in studded tires is a chore. I use a set of Marathon Winters for my 12-mile commute when I need to, and only when I need to, but I hate it. Yeah, for tires with metal spikes sticking out of them they roll okay, but it's still feels like riding on sand the entire way. If there is a high probability that you'll encounter ice, then you have little choice. But 20 miles...😖