Originally Posted by Chuckles1

Have Tiagra road brifters on a bike, new last year, about 1500 miles on it. Have been getting misshifts on RD wherein it downshifts and then upshifts as soon as I release lever. I'm told that's classic case of frayed cable inside shifter. I want to replace only the inner cable at this point.

First time with internally routed cables. It appears that my bike has cable housing all the way from brifters, into down tube, and exiting at BB. In that case, do I need to bother with pushing a guide tube over the inner before removing it, or can I just push the new inner through the existing cable housing just as I would on an externally routed bike.

The cable housing does run under the bar tape, which I recently replaced, so I'm not inclined to want to remove that, since I finally got it the way I like it after considerable effort.