Joined: Feb 2012
Posts: 19,381
Likes: 5,528
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Generally tires with more flat protection also have greater rolling resistance. If the rim is actually dimensioned as the label suggests then the OP could run tires as narrow as 25mm (not that I am suggesting it). Dropping width to about 35 to 32mm, going to a thin tread cap thickness, loosing any tread depth (as in going to a slick) will all up the feel of the tire. Do know that your speed is still much more dependent of bike weight and air resistance, tire rolling resistance plays a tiny role of total friction. Andy