Here are some pictures of the bike with the the 26x2.1 knobby tires and the same bike with the 26x1.25 slicks.







ORIGINAL TIRES 26X2.1



CITY SLICKS 26X1.25



One word of caution in moving from MTB tires to slicks. MTB tires run a lower pressure, say 60'ish. Slicks run higher, say 100'ish. If the rim is double walled, where the spokes attach to the first wall, and the tube lays on the second wall, there will be web holes in the second wall to access the spokes in the lower wall. Those holes are protected by rim tape. If the rim tape is rubber, the rubber will not hold the higher pressure of the slick tire, and the tube will push the rubber rim tape into the web hole until the tube pops (see pictures below). The rim tape needs to be upgraded to a cloth (like Velox) or plastic tape. Search for "rim tape" in the title as there are several threads addressing the pros and cons of cloth versus plastic rim tape.

Picture of hole in the tube:



Picture of where the tube pressed into the rubber rim tape causing the flat:



Picture of a double wall rim showing the web holes: