123123user

Not even cross chaining, but the chain is rubbing on the inner FD plate (the plate that contains the skid plate) thats nearest to the frame when I have my chain on the small gear at the front and at the 5th gear on the back. I can tell it doesnt occur back then -- already went to the mechanic twice. First time he fixed it and after a few weeks it came back and I just went and now its back again. Limit screw seems to not change anything at this point. Mechanic said its normal since it's just hitting the plastic. It's an Ultegra 6800 FD.

123123user

It rubs on the inside, the left part of the cage.

123123user

I could count three clicks from the lowest to highest so I would assume I am already at the L trim for my lowest. Chain starts to rub with the skid plate at 4th gear I think. Is the FD supposed to go even closer to the frame at L trim? I dont have a barrel adjuster for this FD cable.

mpetry912 

if it gets adjusted and then comes back do you have something moving ? Loose crank arm or inner ring boits ?

otherwisek, yes, it's the inner limit screw, needs to be adjusted so the chain just clears the cage.

but eliminate other possibilities first

/markp

cyccommute 

It sounds like the cable is too tight. A tight cable won’t let the derailer move to the left far enough. It’s not a common problem…it usually goes the other direction. You might be having some kind of friction in the cable housing that is preventing the cable from relaxing completely. Check how tight the cable is when the shifter is in low gear. It should be slightly tight but not super tight.

123123user

The first time it happened I had it fixed by the same mechanic. Over time it rubbed again. Did it tighten up on its own or what?

cyccommute 

If the inner cable is corroded inside the housing, yes, it could tighten up over time. Another possibility is a kinked cable inside the cable housing.

A way out their possibility is that the derailer isn’t clamped to the seat tube tightly enough. Look at how the outer plate on the derailer aligns with the chain rings. It should be parallel. Check to see if you can move the front derailer by hand…i.e. spin it on the seat tube. If it moves, you’ll need to tighten the clamp (after properly aligning the derailer). This is very uncommon, however. Clamps are usually tight enough to keep the derailer from moving.

123123user

Been to another mechanic. Best he could do was to allow another gear to be usable without rub. He said the same thing -- that it was normal.


this is the chain at 1x1 config. It wasnt like this before, it had some distance.

cyccommute 

It’s not “normal” if it wasn’t a problem and then became a problem. Disconnect the cable and see if you can physically push the derailer cage back against the frame. While you are at it, see if you can pull the housing down on the cable and inspect it for any kind of corrosion. Cables should be relatively shiny. If it is crusty or white or both, it needs replacement.

Looking at your picture, it looks like there is some corrosion on the front derialer. You might try some lube on the pivot points and work the derailer back and forth after you have seen if you can push the derailer further by disconnecting the cable.

123123user

No matter how I adjust the limit or the cable, it still rubs on the inside.
I noticed that I'm missing a part called the converter from the manual. It seems that the cable is being routed there. Without it i just route the cable around the bolt overhead, coming from left to right. Does it make any difference?

​​​​​​I also found another one who had a problem on his 105 FD solved by changing the direction of the cable route but I dont have the converter pin to apply that.

I ordered the spare part eplacement already just in case.

philbob57

The inside looks like it is
slanted in toward the chainring. I'd expect rubbing from that.

I'd also expect the manual writer to know more than I do.

I wouldn't be surprised if an over-worked or under-competent mechanic avoided putting in enough effort. I don't know if the mechanics you dealt with were uninterested in your problem or incompetent to fix it, but I'd bet it's a possibility.

BTinNYC 

Yes, it did for me, also 105. Let me add, I think this era FDs are consumables, so don't fool around too much before replacing.

79pmooney

Looks like that to me also. If anything, I tweak my FDs to rotate the rear of the FD cage in toward the wheel, not out.

I've had chainrings and chains that shifted so easily that the chain could fall off to the inside in regular shifts. For example, back in the dark ages I started running a Shimano Uniglide as a race chain. I didn't know yet that it required a half turn with the limit screw to not drop the chain on shifts to the inside ring. Dropped the chain on two consecutive hills in the hardest race I every rode (before dropping the chain). Got it back on before rolling to a stop both times and finished with the remains of the field but what a lesson! From then on, I rode with FD rum in small-small and large-large with the race gears and chain. Never had any more issues. I couldn't hear the rub in the pack and was breathing too hard on my own.

123123user

I already ordered the spare part. 4 dollars for that small piece is pretty surprising, but still I don't think the FD is broken enough to be worth spending a full $30. Will be getting back once I have it to see if it changes.
I think I untuned my RD accidentally while I'm tinkering with the front. Looks like the roadie has to act like a fixie for the moment.
The part of the cable that is being tightened is becoming frayed. And I just replaced all cables on my bike not more than a couple of month ago. Is that still ok?

Kai Winters

My preferred method is to start from a fresh install. I inspect, generally replace the cable and housing unless they look and feel like new, the cable and housing for corrosion and also for tight bends which can restrict the smooth movement of the cable in the housing resulting in sticky shifting.
I disconnect the cable from the pinch bolt on the front derailleur then shift onto the small chain ring, which occurs when disconnecting the cable, and the easiest gear on the cassette/freewheel. Using the trim screw I adjust the front der. until there is 1-2 mm of distance between the chain and inner place. I check the front derailleur adjuster, if it has one and may be placed between the housing , making sure it is in a near closed position, meaning turned almost all the way in for the least amount of cable pull/tension... I always leave several turns from the bottom for tension adjustment increase or decrease tension. I check, by holding the cable in my hand with some tension, the shifter position by pulling on the cable and shifting up and down and leaving it in the least position...small chain ring position. Connect the cable to the pinch bolt making sure it is in the correct location on the der. and the tension, you are pulling the cable taut but not crazy tight. Tighten the pinch bolt. Shift from the easiest cassette gear a couple and shift onto the big chain ring. Shift down to the hardest gear and check the spacing between the chain and outer der. plate...it should also be around 1-2 mm. Shift up and down the rear derailleur checking for der. rub. Shift to a rear gear at the mid point of the cassette and aggressively shift up and down the front derailleur checking for proper spacing and that the chain doesn't derail. Shift onto the small chain ring and easiest cassette gear checking for proper spacing. If good you are all set. If it needs a bit of adjusting you can use the barrel adjuster to increase/decrease the cable tension until it is correct.
Good luck and keep us informed.

Maelochs

Ultegra 6800 front derailleurs are very sensitive about where you run the cable, depending on where the cable feeds up through the frame. Set up properly, they will not rub at all, in any gear .... having ridden one for nine years without rub, I feel qualified to make that statement.

Lots of good advice in this thread .... including, I hope the idea that you don't ever go back to the guy who failed to fix it reopeatedly but still charged you.

I looked up Shimano's own advice for setting up the 6800 FD ... they even make a special tool or guide to determine which side of the bolt you should run your cable. Check it out. I'd link but I am late for work.

123123user

I have attached the converter I bought today and I definitely have a big improvement. Theres no rub until gear 1 which is pretty acceptable for me now. However I wonder how long do these converter last... They dont even seem to have a true locking or tightening mechanism, like they just get put there following the shape of the hole