You want to initially mount the derailleur so that the rear of the cage is angled slightly in a few degrees, and the bottom of the cage is 1-3mm above the teeth of the large ring. There is an angle adjustment screw on the derailleur (see image), you will turn this in until the derailleur cage is parallel with the large chainring. Its important that this screw does not contact bare carbon on your frame, it should either be against the derailleur mount or band clamp, or Shimano has little adhesive metallic protector pads to go under it to protect the frame. Once the derailleur is aligned properly, you can then adjust the high/low limit screws...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

The Shimano service manuals are very good. http://si.shimano.com/...DM-UL0001-03-ENG.pdf Page 26 onwards. Best to use use the mounting bolt, not the support bolt for the cage alignment.

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Developing aero, fit and other fun stuff at Red is Faster

The proper way IS to use the support bolt for alignment.
Exactly as described in the post above yours.

What I was noting was it's a support bolt not a rotation bolt. As per Shimano's instructions, you load it up to set the alignment, having assembled the mech in the correct position. Yes, the mech moves out as you load it and that sets alignment, but it's purpose is to support the mech for upshifts.

What I didn't want was an inexperienced person using it to try and set the alignment from scratch.

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Developing aero, fit and other fun stuff at Red is Faster

Thanks for the responses, but that support/adjustment screw rotates the hanger further in the wrong direction for me, becoming more unparalleled. The derailleur was mounted when the Bike came and I don't see any method to change the angle of the cage or mount. Is there a way to alter the mount? It appears static due to the holes in the frame and I only see side to side rotation in the upper bolt where the mount attaches to the frame but that doesn't affect the rotational axis where my issue is. I don't see any similar flexibility in mounting the derailleur to the mount to correct my issue. Are there any tricks to change the angle of the mounting?

Have you tried backing the support bolt out a few turns first, and then loosening the front mounting bolt on the derailleur? This should allow you to angle the derailleur slightly inward, then tighten the mount bolt, and then use the support bolt to align the cage with the chainring.

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"I'm thinking of a number between 1 and 10, and I don't know why!"

This is really simple stuff and the OP has so far shown that he cannot grasp it.
You are far better off to take it to a bike shop where they will take all of two minutes to sort out.

I had the same problem. The support/rotation screw was too far out when mounting the derailleur. Even though I backed it out when the FD was mounted it was too late as the FD was already set in the wrong place having been pushed out by the screw

Remove the FD and back out the rotational screw until it is flush with the body of the FD. Then remount the FD, you should now find that it is in roughly the right place. You now need to screw in the support screw until it contacts the braze on clamp or the sliver stick on piece that comes with the FD. If it needs align you can use this bolt to push it out slightly.

UPDATE - Ended up taking it to the LBS - he loosened a mounting screw which reduced the pressure and allowed the front of the hanger to come close to parallel. Problem is, it still doesn't allow me all my gears and this dream of smooth shifting on Di2 is yet to be realized. So now I have a front derailleur mounted at less than 2Nm torque in order to get about half of my gears to work. Obviously not riding this new bike this weekend in Omaha and tempted to send it back to the manufacturer.

I really don't want to send it back because I like the bike and the feel of it - but if I can't shift its worthless. Also, the bike whistles! The manufacturer claims that Profile Design puts the holes in the bottom of all there aero bars for running cables. I emailed the rep and that was her response - but the issue is the holes are not where I would run cables and not an aero location. So when I got it out it whistled the whole time - obviously the air is catching as it stopped as soon as I covered the holes. See photo below. I looked on the website and there aren't any plugs available from Profile Design which I would expect if this is in fact typical.

I assume my next step is to find another LBS and hope they have more experience with Di2? Or do I take a risk and bring it to Omaha and hope the prerace mechanics can mess with it on Friday?

Maybe you front derailleur change is bent backward slightly? I suspect that the bar doesn't catch air with cable in them. You may be stuck using electrical tape on the holes.

How did you fix that at the end?
I have similar problem on my 2020 Venge

I had something similar to the OP's problem (and presumably yours) on my Felt AR. Ended up needing to bend the braze-on just a tad, so that I could get everything to align.

...As in, your derailleur won't sit parallel to the chainrings?

If so, have you adjusted the support screw that sets the parallel position of the derailleur? If not, check out Page 39-40 in the shimano manual for instructions on how to adjust the support screw

The problem is that the derailleur is angeled outside even when that bolt is not even touching the frame... and the other problem is that when i get 1-2mm space at back of derailleur then i have 4mm at the front and when i set 2mm at the front then back is rubbing at the chainring.

I don’t have any rubbing or shifting problems.
But... i spotted that because i had chainsucks when i downshift from bit to small. But i cannot see how that can be caused by this angles...

I had the exact same problem with a Dimond Marquise that I worked on: RF-8050 angles outward at the rear. I didn't discover a good way to adjust this and think it was caused by the hanger being out of alignment. Tightening the support bolt made it worse. Also, I want to point out that the support bolt is not there to adjust the angle of the derailleur (as some have suggested in this discussion), it is to give it a point to push against when it shifts into a higher chainring (it's a support bolt not an angle adjustment bolt). I fixed the bike by gently and gradually bending the derailleur inward with my bare hands until it was parallel with the outer chainring (don't try this at home). This video is helpful but a little slow. Also relevant to some comments in this discussion: the RD-8050 derailleur is programmed to not shift into the smallest 2 cogs in the rear when the chain is on the front chainring as part of Shimano's gear position control.

I think this is an example of flawed equipment. Hangers get bent, and you can't adjust the angle of post mounted front derailleurs. I have a tool for easily adjusting rear derailleur hangers, but as far as I know there is not one for front d-hangers. I think Shimano should engineer front derailleurs so that the angle is adjustable.

Could you clarify this? I just got my di2 bike sorted by a mechanic yesterday and noticed something similar. Do you mean, if the front is in the little ring the rear won't go to the 2 smallest cogs? And is this in full manual mode as well or just synchro shift if available? I get why in synchro shift it would be a thing, but in full manual this feels like a big oversight in di2.

Yes, that's exactly how the gear shift control works on the 8050 and some other 11 speed Di2 in full manual shifting: if the front is in the little ring the rear won't go to the 2 smallest cogs. Check out page 127 of the dealer manual. You can decide to live with this, which is what I recommend, or you can change it by connecting your bike to a Windows computer, see description here.

Go into the e-tube software and "lie" to it by stating that the crankset is a 53/39t (and/or the cassette is 11/25t). That combination should allow one to be on the small chainring and use the two highest gears of the cassette.

The front derailleur angle IS adjustable. However, a particular frame's seat tube shape or derailleur mount might prevent it from being able to be adjusted. All of the bikes I own allow Shimano derailleurs to be adjusted with a pretty wide range, wider than would be needed.

The derailleur could be angled in slightly more on this frame if the seat tube had been round on the trailing edge, and if the mount was just a hair shorter:




And angled outward:




I have seen frames where the derailleur could not be adjusted inward or even straight, but this is a design fault of the frame manufacturer, not Shimano...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

Exactly this. Not only is the front derailleur adjustable, but Shimano is quite good about publishing the specs for where the hanger needs to be positioned. It's really not their fault when manufacturers mess this up.

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Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
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