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I have a Giant road bike with Shimano Ultegra gears.

The outer side of the front derailleur is making contact with the chain, on both crank chain rings, when in the highest gear at the rear.

I have fiddled with both high and low adjustment screws but cannot get the derailleur to move enough to stop contact.

The derailleur is parallel to the crank.

Would anyone have any ideas?

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  • Front derailleurs are fiddly things - can you add some well-lit photos to your question?
    – Criggie
    Feb 11 at 8:55
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    Lack of cable tension? If there isn't enough, the FD doesn't come out enough to not hit the chain. Not to be confused with the limit, so first make sure that the FD can be pushed into a position manually where it doesn't scrub...
    – DoNuT
    Feb 11 at 9:24
  • Is it possible the front derailleur has suffered an impact and is now bent? Or it may have wear in the pivots and is no-longer able to get-over as much as it needs to?
    – Criggie
    Feb 11 at 23:52

2 Answers 2

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There are two main factors that decide how much the front derailleur moves

  • Limit screws
  • Cable tension

The resulting derailleur movement may be limited by either of them, so you have to get both parameters right, but it seems you only tried limit screws.

It should be fairly easy to check what the problem is:

  • If you can manually push the derailleur out further than it is positioned by the cable -> increase cable tension for additional movement
  • If the derailleur doesn't move outward even though the cable is tight, it might just be stopped by the limit screw (too early)

The fact that it rubs on both chainrings sounds more like lack of cable tension to me.

On a side note: This adjustment may go off on a once perfectly set up bike, for example by cable stretch. I also had a problem with inline cable adjusters that gave in half a turn, decreasing tension and leading to rub.

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    You were right - it was the cable tension.
    – MeltingDog
    Feb 11 at 22:49
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Go and purchase an Ultegra Di2 front derailleur as they are more accurate and now have a "self - trimming" feature within the app.

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    I would rather turn the barrel adjuster half a turn than spend 190$. A full turn might even be preferable :). But to each their own.
    – WornChain
    Feb 15 at 22:02
  • This isn't a very good answer since it would also require a Di2 shifter.
    – Paul H
    Feb 16 at 5:32
  • That's a very expensive solution. By the way, isn't the "self-trimming" trimming in the classical sense, so going to the "middle positions" when your run certain chain angles and avoiding rub - most mechanical groupsets have that features, too. Certainly 11/12-speed Ultegra. This wouldn't help if the initial adjustment is off - or are DI2 front derailleurs like "Oh, I'm rubbing, so I'll adjust limits."?
    – DoNuT
    Feb 16 at 9:04

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