Routing cables on the top of chainstays and other alternatives for cable placement

[gorkypl]

I am in a process of designing custom frame (allroad/gravel), and probably will go with titanium as material (alternative being steel).
What I still cannot decide upon, is the cable routing. It will be mechanical 1x, so two cables (hydraulic brake + wire shifter) going to rear triangle.
I want it to be at least semi internal, as this will be a bike I will travel with, and want to protect the cables as much as possible.

What I don't like in most of the designs is routing the cables below BB after they exit the down tube, I have seen hydro lines damaged by stones and I don't want to risk it. However, I am not sure that routing both shifter and brake cables through BB will be possible. Even with T47, I am not sure if there will be enough space.

Lately I have seen some builders (especially Stelbel with the Nina model) routing the cables *over* BB and then guiding them on top of chainstays. I have to say I am a bit tempted to try it, but I am not sure if this is a better solution overall. My biggest concerns are problems with cleaning the frame around cables, and possibility of mud and debris from the rear wheel damaging the cables. The chain will also probably be hitting the shifter cable on bumps.

Do you have any thoughts on this? Or any other ideas?

[ooo]

Use bicycle hydraulic hose + non-bicycle "DIN EN 853" industrial high pressure hydraulic hose (ID 6mm) as a sleeve protection layer over bicycle hydraulic hose (OD 5mm) for externally routed part



You can also use chainstay protector (with custom frame, you can add mounting points for removable 3d printed protector)
https://www.amazon.com/Lizard-Skins-Neo ... B08LJ6JW8Y

[ms6073]

Do you have any thoughts on this? Or any other ideas?

My last true mechanical/hydro frameset was carbon with a BB30 bottom bracket and had cutout/molded cable guides on the underside of the bottom bracket and the rear brake hose ran internal of the NDS stay and could be routed either over or under the bottom bracket. Not apples to apples, but before I got my C64, I had a Scott Solace disc that had a BB86 bottom bracket and the rear hydro hose could also be routed either over or under. In all cases, I opted to run the rear brake hose over the top of the bottom bracket, but it was easier with the BB86 as I used a BBInfinite bottom bracket which shields the spindle from the hose.