That tire article was interesting--maybe I can't blame it all on the tires after all! It's more likely that I'm just plain slow, given my 10-11 min/mile running pace and the fact that I was never a speed demon on the swim team either (however, if I go to the local Y to swim laps I blow by a lot of people even though I generally swim a 500 in about 10 minutes--there's more of a range of swimming speeds there). I will probably still give that group ride a try in the next few weeks and see how it is, but I'm starting to get the feeling that I might do better to just ride at my own pace.