Old 02-14-17, 10:26 AM
  #27  
Andy_K 
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Thanks for updating, @joejack951!

I'm not sure about the 5800 data. I've got a set of those levers, but they're hooked to disc brakes without a simple release that would give me complete access to the relevant points, but as I recall the reasons I didn't include that were (1) the cable attach point was such that the measurement wasn't easy to perform accurately, and (2) the lever is designed such that it wraps the cable around an irregularly shaped surface.

The second point here is the relevant one. Anyone better at measurement than I am (which is almost everyone) can address (1), but (2) is an intrinsic issue with how this lever pulls able. That is, the method I was using depends on measuring the radius of the circle being traversed by the cable, but with the 4700/5800/6800/9000 levers this radius is variable so the lever pulls cable at a different rate at different points in its motion.

Note that this corresponds to what Shimano says about the change in cable pull from the 4600/5700/6700/7900 ("New Super SLR") to the 4700/5800/6800/9000 ("SLR EV"), which is that the cable pull is compatible but that it pulls at a different rate.

So, as a sanity check, our measurements should indicate that the cable pull rate of a 5800 lever is very similar to the cable pull rate of a 5700 lever. I'm not saying that the measurements shouldn't be the final word, but I am saying that if the measurement is significantly at odds with expectations (which yours is) then it should be double-checked.
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