This is a general question, regarding the routing of the cables of both brakes and derailleurs on a frame.
I find it highly practical to mount all cables along the bottom of the top tube. This offers the following advantages:
- The wide down tube protects the cabling from mud and gravy, originating at the front tire
- The top tube can support weight e.g. sitting* there or supporting luggage.
What are the reasons of the other cabling schemes? I am most puzzled the combined scheme "2 cables on bottom of the bottom tube + 1 cable on top of the top tube".
* one of my pleasant habits is, when there are no free seats in the park and the grass is wet, sitting on the front tube, with the bike tilted, one hand on the brake and the other holding a beer