it's not clear you need to change anything without knowing what you have. I've got two bikes set up as doubles that have low enough gears. One is a triple with the outer gear occupied with a chainring guard. It's got a 44t and 30t. with 12-32 in the rear. The 44t is a middle position so I can use the entire range of the cassette. Put in a narrow range cassette and you've got a commuter set-up. The other bike has 34/48 chainrings with 13-34 cassette. Only difference I can see between a utility bike and touring bike is that the utility bike has more of an upright riding position with ease of dismounting and the touring bike is closer to road bike for higher output.