11 Speed Shimano FD Positioning

[gt eunuch]

So... CAAD7, 5800 group, 25mm tires, running a braze on FD with a Shimano adapter.

What can I do to get the pinch bolt to be further away from the tire? I would prefer to move the cage outward a little bit more (it rubs when pedaling hard in teh 2 smallest cogs), but doing this makes the pinch bolt foul the tire, so I am kind of stuck.

Would a clamp on FD help/hurt this? A different model FD? Another adapter? Am I taking crazy pills? Help me Paceline forum, you're my only hope.

[Masaoshiro]

Is your H limit screw too loose?

[beeatnik]

9100 fd

[gt eunuch]

Originally Posted by Masaoshiro

Is your H limit screw too loose?

I would say no. I am not able to push the derailleur any closer to the tire at this point by hand (because well, the limit is stopping it) I would like to loosen it just a touch to get more clearance between the chain and the cage, but even 1/4 turn farther puts me way too close.

[jbreebs]

I learned something new at the shop I work at last night, hopefully it will help.

If you look at the FD from the drive side, through the gap in the arm, there's a small screw that sits inside the mech, just below the spring and behind the mounting bolt. It's a 2mm bolt, and turning it clockwise will push it through the back side of the derailleur towards the seat tube. This screw is intended to push against the seat tube and allow you to adjust the angle of the cage outward a bit.

New bikes come with a small piece of metal with a sticky bit attached - this sticks to the frame and the bolt presses against this. If you don't have the small piece of metal, maybe you could get one from a shop, or just stick on a something to protect your frame. If you're lucky the braze on tab sticks back far enough that the bolt will hit it instead of the seat tube. Or just let the bolt hit the seat tube, your call. This allows you to move the cage out and hopefully stop the rubbing. You also need super high cable tension, so you may need an in-line adaptor to adjust the tension if you don't have adjustable cable stops. Hopefully that will stop the rubbing. Not much can be done about moving the mounting bolt though :/

Edit: This video might help
https://www.youtube.com/watch?v=hlbenKUx9JM

[Masaoshiro]

Thats strange.
What size tires are you running?

[DrSpoke]

A friend of mine had this issue on his Specialized Diverge. I ended up hand filing the curved portion of the FD where it interfaces w/the braze on mount. It only had to remove a couple of mms to move the FD forward enough where the arm no longer contacted the tire. Since I did the filing by hand it's not a perfect interface w/the braze on but when tight it was fine and has been working for the last year or so.

The 9100 suggestion is a good one as Shimano changed the arm/pivot design - likely for this very reason. That would be my recommendation as of now though it wasn't available as an option when I did my hack.

[gt eunuch]

Just to run through tonight's current findings.

I am already using the set screw, with the little piece of sticky metal attached to the frame to brace the fd against the seat tube. I re-adjusted this a few times tonight, no change.

The little adjustment arm for cable angle on the front derailleur was already set where it 'should' be based on the little plastic cable guide thingy, but I tried to flip it, and set it all up again. This did not seem to help clearance at all, so I put it back where it 'should' be, and re-setup the fd.

I mean, it doesn't touch, so it should be fine, right? I have just never experienced clearances this tight.

[AJosiahK]

Originally Posted by beeatnik

9100 fd

Agreed

[Cicli]

Originally Posted by gt eunuch

I mean, it doesn't touch, so it should be fine, right? I have just never experienced clearances this tight.

If it dosent touch, run it. Problem solved. Its an issue of short chainstays, angles, and that derailuer design.

[stien]

You might try rifling through your parts bin for a bolt with a lower profile head, and see if you can live without the washer between cable and bolt head. That'll bring it in bit.

[m_sasso]

Which BB and crank set are you using? What is the the gap between your inner chain wheel and chain stay like?

[12snap]

I had a similar problem. I switched to a clamp on derailleur instead of using an adapter with the braze-on derailleur. The clamp on derailleur moves the whole assembly further forward and solved the problem.

[zennmotion]

If you're running a 5800 group, then a 9100 FD is kind of a budget buster. I had the same issue with 5800 FD, though it was because I was using fat 32mm tires. A Shimano CX70 FD works just fine with a shorter arm (with my compact 34/50t rings, YMMV with larger rings, but I bet it would work fine with a 39/53) at a fraction of the cost of 9100. It requires a relatively high cable tension, but once set it works great. Pro tip for setup-
1) Set your small ring limit screw first.
2) Then screw your FD cable barrel adjuster in (clockwise) all the way
3) Pull your cable as tight as you can when adjusting for the small ring, if it's not tight, the FD won't carry over far enough when you shift to the big ring. I use an old school fourth hand tool to grab the cable or you can use pliers to pull it tight (careful not to damage the cable!).
4) tighten the pinch bolt,
5) back the barrel adjuster out a turn or two to tighten any slack out of the cable, sort of like tuning a guitar string.
6) Shift to the big ring, adjust the big ring outside limit screw

I've rarely used barrel adjusters with FD cables before, but the difficulty with Shimano 11speed (at least with the CX70FD that has a shorter arm than 5800) is getting the cable tight enough, any slack and you'll have difficulty getting the derailleur cage to shift over far enough in the big ring. If you're using a CX70 FD (or other FD with a shorter arm, a Shimano 9/10sp FD might work as well), taking the slack out with the barrel adjuster makes setup and proper adjustment much easier.

[zennmotion]

Originally Posted by Cicli

If it dosent touch, run it. Problem solved. Its an issue of short chainstays, angles, and that derailuer design.

In this case, stay off muddy or damp roads where your tires might pick up some sand and grunge. And hope you're never sloppy about getting the rear wheel perfectly set at the top of the dropouts every time. Or use a different tire with slightly different dimensions. In other words, too close for comfort IMO- and a bike in a repair stand and a bike on the road may have different tolerances.