Author Topic: Ultegra ST-RS685 LH Shifter Operation  (Read 319 times)

Ultegra ST-RS685 LH Shifter Operation
« on: January 29, 2020, 07:40:21 pm »
I've just taken ownership of a bike fitted with Ultegra ST-RS685 shifters.  They're working beautifully but I have noticed that there seems to be 3 distinct shift movements on the LH lever.  Firstly there's the small "trim" shift from the big ring, then a second shift that puts the chain on the inner ring then a 3rd shift that puts the FD fully over to the left.  I'm guessing this is normal but I'm not sure why??
Most of the stuff I say is true because I saw it in a dream and I don't have the presence of mind to make up lies when I'm asleep.   Bryan Andreas

Re: Ultegra ST-RS685 LH Shifter Operation
« Reply #1 on: January 29, 2020, 09:17:59 pm »
See page 20 here:
https://si.shimano.com/pdfs/dm/DM-RAFD001-04-ENG.pdf

It’s an admission that it’s impossible to build an indexed mechanical front mech that shifts reliability *and* never rubs.

Re: Ultegra ST-RS685 LH Shifter Operation
« Reply #2 on: January 29, 2020, 09:31:23 pm »
Thanks Grams, that explains it :thumbsup:
Most of the stuff I say is true because I saw it in a dream and I don't have the presence of mind to make up lies when I'm asleep.   Bryan Andreas

Re: Ultegra ST-RS685 LH Shifter Operation
« Reply #3 on: January 30, 2020, 02:05:42 pm »
this might be helpful too

https://forum.cyclinguk.org/viewtopic.php?t=124598

but some of the picture links seem to be broken.

cheers

Re: Ultegra ST-RS685 LH Shifter Operation
« Reply #4 on: January 30, 2020, 10:10:18 pm »
Thanks Brucey, that is very useful and explains my frustration in setting up road indexed fds in the past and indeed the current trend towards 1 x drive trains. 
Most of the stuff I say is true because I saw it in a dream and I don't have the presence of mind to make up lies when I'm asleep.   Bryan Andreas