-
I'm not arguing one way is the only way, but is there a reason shimano chose to present two different methods? Efficiency? Better shifting? Is this sort of matter in the same ballpark as the TL-FD68 cable routing tool (added complexity for the sake of it?)
Philip_J_Fry-
is there a reason shimano chose to present two different methods?
I can't get inside the head of the guy who wrote the Shimano Dealer Manual (as we must now call it, since they have recently decided that mere cyclists can't be trusted with assembly and maintenance operations more complex than "wipe over with a damp cloth, and take it to shop for anything else"). Given that Shimano RDs float on the B-tension spring, the idea of finding a vertical seems unnecessarily challenging. You could set it up at first with the centres of the two pulleys aligned vertically, and then adjust the B-tension to optimise the gap from the upper pulley to the sprockets and find your vertical was no longer vertical. Perhaps they just gave the 27T instructions so that proper race bikes would be set up like that and would look good in the product shots :-)
gbj_tester
The method works for SRAM too, as shown in their manual