I have replaced the shifter and brake cables on my 105. I did rewrap the handlebar tape, actually a few times on the wrapping. I changed to Sram Ride on cables and greatly improved the shifting and braking over the original set up. I took out the in-line adjusters that were cracked and failing. Shifting went from " lazy " to more precise & crisp. I use Pedro's Cable cutters & get good sharp edges without crimps or frayed edges, then put a crimp cap on the cable. There are two different types of cable housing for the brakes & shifters. Good luck, it was well worth it for me. Andy