My Sirrus currently has 28c spesh Nimbus tyres (plain on the front, armadillo on rear). I use the bike for winter ERC club runs. Now they are wearing out I'm going to replace them. I'm thinking I'll put something a bit narrower on 25c's but reduce the rolling resistance but perhaps more grippy than the nimbus. I've been impressed with the continentals on my other bikes and I think I've narrowed it to 4 seasons or Gator skins. What's peoples opinions of these tyres?