A farfetched thought occurred to me.
The shifting system of a bike relies on tension to pull on the derailleurs to shift gears. Too lose and it might not shift up properly. Too tight and it might overshift. Thus, tuning up the shifting system requires adjusting the tension at the cable fixing bolt or the barrel adjusters.
Problems occur over time as the cable stretches which reduces the tension on the cables thus requiring adjustment. Othercourse, I am sure there are other problems that occur in the shifting system with use such as wear but bear with me.
What if I were to measure the tension of the shifting cables after the bike has been perfectly tuned up and then, before every ride thereafter, somehow measure the tension of those same cables and adjust them until they reach that same tension that was had when the bike was in perfect shifting state.
Park tool has a tool to measure the tension of the spokes, a similar or perhaps even teh same tool could perhaps be used to measure the tension of the cable in various positions.
Would this idea actually work or am I missing something?