Ok I read and post here alot now we talk about wheel sets or what kinda of tire... But I never hear to much discussion on tire size. Right now I am running 28's. But I have been known to encounter gravel on my trips. What do you as a community think would be a ideal size for touring tires. I am talking all around, like gravel to road and so on. Then for a side banter, What kind of tread?