Warning: I ran brake cables through the frame with zero grease for 2 seasons and just found rust
I used to think internal routing meant the housing was sealed in there safe, so I skipped any lube and just shoved the liner through. Pulled a rear brake cable out of an alloy frame from a Chicago commuter bike and the inner wire came out brown and gritty after maybe 1,800 miles of winter salt. Does anyone else grease the full housing run on internal routing, or am I the only one who learned this the hard way?
Is a little surface rust on the inner wire really a big deal, though? Cables are cheap and you would swap them every couple seasons anyway, so I have a hard time seeing this as some kind of crisis. Seems more like normal wear than a reason to start packing every housing full of grease.