OMG ... Rolling Resistance! I changed from my Trek Pilot 5.2 to my old Trek 720multitrack (heavy steel) with Nokians and if feels like I'm riding in sand ... uphill! I seriously can't believe how slow this set-up is. We are expecting a foot of snow tonight so tomorrow's commute should be a nice challenge . How deep is too deep to ride in? I'll try to throw pictures up tomorrow.