Internal cable routing - stickiness

[richardg]

I ride a De Rosa King 3 which, like a lot of top-end bikes has internal cable routing. I have repeated problems with the cable for the rear deraileur dragging in the downtube internal routing, especially after a few wet rides when road gunk must somehow be entering the cable channel. I can resolve this partially by removing the gear cable and letting the internal 'tube' dry out which can take days, then lubing it and re-fitting. Does anyone have a better/easier idea of how avoid or resolve this problem (not riding in the rain isn't an option here ?

 

[AnythingButKestrel]

I've been through a pile of frames and have yet to beat it. Guess what? My new frame will have conventional, external cable routing. Some manufs may have it figured out, but it seems others just aren't ready for prime time.

Sorry, I know that doesn't help. Maybe you could try sealing the entry points at the cable stops with RTV or self-fusing tape.

 

[James Huang]

Is the shifting good when you start with new cable and housing? And if so, you're then saying that it only starts to go south when you've been riding in the wet?

In that case, I'd say a set of sealed Gore cables should solve your problem. It's lower-friction to begin with but more importantly, sealed from dirt and debris so that you don't have to swap cables nearly as often in bad weather.

 

[richardg]

Thanks James, I'll try the Gore cables.

 

[nzuraw]

Had a similar problem with my rear brake cable. My local (and very good) bike shop spoke to De Rosa and recommended drilling out the internal sheathing and replacing it.

That worked! They also sealed the entry points to eliminate water or debris getting in. It wasn't so much an issue with the cable more restriction in the sheathing. I believe De Rosa have modified their design for the new frames as did Pinarello (who experienced the same issue on some of their frames).

 

[richardg]

The Gore ride-on cables did the trick, fitted them a few months ago and the shift is still good. The fitting instructions supplied with the cables were really poor, but found some clear instructions on their web-site.