Ultegra front mech/shifter issue

crescent

My 2018 BMC has a full Ultegra groupset - it has been a joy to use in the last 5 years of ownership. However, recently I am finding that when I have used the front mech trim function on the big ring, I cannot move it back to its previous position without shifting all the way into the small ring and then back up again. Example scenario : I am in the big ring and in the smaller/outboard cogs of the cassette - I move up the cassette and as the chain begins to rub, I use the trim to move the front mech inboard slightly - all fine, so far. When I then start to move down the cassette again and try to return the mech to its fully outboard position again, it will not move without being dropped into the smaller ring and moved fully to the big ring again. It feels like the shifter might be the issue but I am not aware of any adjustment at that end. All the groupset components are original and I keep my bike scrupulously clean, lubed etc. All the cables are internally routed but appear in good nick as far as I can see on the short external sections.
Any advice please? Thanks.

webboo

Have you changed the cables. If not it may be they are fraying round where they go in to the brifters and this could be the issue.

crescent

Thanks, Webboo.
Yeah, when I read my post again, it struck me that 5 years is quite a while to go without changing cables. Because it has all worked so flawlessly I was reluctant to touch anything (why would I?), but it is a fairly simple matter to try it and at least eliminate it.

Cheers

crescent

Front and rear cables have now been changed out for Jagwires. There was no obvious signs of the cable fouling at the lever. What was quite surprising to me was how complicated it is under the hood, compared to other groupsets, there is a lot going on in there. I'm still not convinced that there isn't a problem with the shifter. I installed the new cable, and even just holding it under tension with my hand, i.e. not routed through the handlebars/frame, the shifting didn't feel as slick as it has been in the past - moving it as if shifting into the big ring is still quite stiff. However, once fitted, the shifting does seem to be improved although the original problem is still there. It's the first time I've worked on Ultegra equipment, it's very good but surprisingly different in terms of limit screws, tension adjustment etc.

Munsford0

Were the old cables the PTFE coated Shimano ones? I recabled my son's 6800 when the rear shift cable started to fray in the shifter. Couldn't believe how much fluffy black cable coating was gumming up the outers and internal cable runs. On some sections I struggled to pull the cables out. Took some really determined dyno-rodding with a spare length of normal cable to poke it all out.

Replaced with Optislick cables and shifting like new...

crescent

Yeah, there was quite a bit of residue when I pulled them out. The new ones were also Teflon coated, so hopefully will help. To be honest, the changing is as good as it's ever been. I'm wondering if I have imagined this fault. Does anyone else's Ultegra front mech do the same?

hpaul

It will ease with more use. I changed mine a month ago, getting easier with every change I think. Still not as easy as my 5 year old propel 105 5800 that I've never changed. Figure that one out

trevor.hall12

If its R8000 are you making sure you do the the half click down when in the big ring when doing set up ,then lining up the lines on the FD with the small grub screw ?

crescent

trevor.hall12 said:

If its R8000 are you making sure you do the the half click down when in the big ring when doing set up ,then lining up the lines on the FD with the small grub screw ?

Good shout. I'm away for a week or so from tomorrow. I'll start from scratch when I return and see how it goes. Thanks.