There is a plastic liner that goes from the underbottom bracket guide, up through the frame between the chainstays, as a guide for the inner. I was replacing the cables yesterday and noticed this plastic liner to be a bit tired, raggedy and cruddy. I gave it a squirt out with gt85, but am sure it’s causing a bit of drag.

Question is, do I need it at all, assuming I can poke the inner through without it ? I am assuming it’s not ‘weight bearing’ such that removal will cause the inner to saw a hole in the carbon, but could do with knowing first 🙂

Replace it. Slide the cable through. Pull off the old sleeve and push the new one on?

yes, think that’s the best bet. Just need to find the stuff now….think it’s 3mm OD very thin walled sleeve tubing, dunno it it’s heat shrink tubing, googling away here to try and find it !