So in the tiny world of bicycle hardware it is kinda a pain in the ass to sort out pull ratios and indexing. I’ve been messing with some custom stuff while rebuilding my road bike. I have a 2012 Sram Red shifter pulled apart. On a whim I started modeling the spool that cable is pulled around and quickly noticed it is not linear. The cable is very intentionally pulled around an eccentric that is offset from the center axis. No one accounts for this offset and nonlinearity in adaptors or forum posts that I have found. I started building a test jig for measuring the pull of every index position of Ultegra using a dial indicator. I am curious how that nonlinearity is mirrored in the derailleur travel.

That got me thinking of new ways to alter and tune indexing better using a set of wedges with one clamped, or an adjustable spool micro assembly to tune the pull.

While eating lunch I got to thinking, the index shifter barrel assembly is all about designing for the manufacturing processes. I bet I could make something totally different with a compliant print in place mechanism.

I mostly stopped using 3d printing file sharing sites because people are generally bad at modeling stuff right, like picking a valid reference for the origin and building the part from there. I gave in to looking for what others had shared in this niche. I am surprised I do not see any printed road shifter designs tried and posed.

Do you have this happen often? Where a subject you dive into seems like the people miss critical information or lack the heuristics and depth to pay attention to the details? Title is hyperbole.