thundermustard

I am stumped. I have Ultegra SL derailleurs. I have adjusted them in the past, while not a pro, I am not a novice.
I have adjusted the rear no problem, the front is giving me problems.
No matter which of the two adjustment screws I turn, or which way, the derailleur isn't moving.
I have the rear derailleur on the biggest gear, the front on the smallest. The cable is attached to the front derailleur and is pulled snug.
I turn the screw closet to the frame and nothing happens. It is about half way unscrewed and I have tightened it all the way and loosened it.
What am I doing wrong?

HillRider

First, disconnect the cable entirely, then try the limit screws.

thundermustard

Cable disconnected, cage will not move regardless. Unscrewed both screws all the way, tightened both all the way.
Does this mean I have a defective derailleur or have I just screwed it up by tightening/loosening them too much.

FBinNY 

The limit screws are just that - they determine the inner and outer limits to the range of motion. They are not designed to control the motion, which is done by the cable, counterbalanced by the return spring.

Back off both limit screws and, with the cable off, push the actuator arm (where the cable attaches) to move the FD and release for the return spring to bring it back. Once you've established the range of motion, you use the limit screws to determine the innermost and outermost limits to that range.

Adjust the return spring limit (usually the inner) to position the cage properly over the chainring, click the lever to the right position, then attach the cable, pulling out as much slack as possible. Now use the lever to shift to the other ring, or rings and adjust that limit appropriately, then use the cable adjuster screw to make the FD index properly (if it's index), or adjust out any excess slack.

thundermustard

The cage does not move, screws are backed out half way or so, loosen screw, tighten screw, no movement. Cable removed, shifter shifted so that the cage is all as far toward frame as it can go.

FBinNY 

It's possible that the FD is defective, or else it might be jammed someplace on the bike. Remove the derailleur, and work the actuator in your hands. If it still doesn't move it's most likely defective, or possibly something dried out on the pivots binding it. It's OK to use a bit of force to try to pop it free, but use common sense so as not to void any warranty.

If the cage and arm are still frozen off the bike, I'd bring it back to the point of purchase, and ask them.

If it works in your hand, but not on the bike, use your eyes to figure out what's holding it frozen.

Codys311

OK, so I think you might need to read over FBinNY's post again. The main idea being that the limit screws do NOT move the FD cage around (mostly). Instead, they provide the limits (one screw inner limit and the other screw outer limit) of the cage's range of motion.

Also, I should mention that with the cable removed, the cage should be as far toward the frame as it can go regardless of shifter position. If the shifter is still moving the cage around, the cable has not been properly disconnected. With the cable removed, the screw that limits the inner range of motion of the cage (L screw) will be the only one that moves the cage. This is because the cage is sitting at its inner limit and so by rotating the screw, you're changing the position of that limit. I hope this makes sense.

Now as far as properly adjusting the limit screws on the FD, the best guide can be found here: https://www.parktool.com/repair/readhowto.asp?id=75 under the section 'Front Derailleur Limit Screw Settings.' Read it. Follow it. Good luck.

Panthers007

Here we go again - this small component causes the biggest problems - so much so that I offer forth my generic copy & paste How To:
_____________________________________________________________________________________

Take the cable off the FD. Now install it from scratch as per Park Tool Repair:

https://www.parktool.com/repair/readhowto.asp?id=75

And BicycleTutor:

https://bicycletutor.com/adjust-front-derailer/

When you have it properly trimmed and are ready for the cable - a new one wouldn't hurt - you want to pull the cable taut - not too tight, taut. Then apply 48 to 60 inch-pounds to the pinch-bolt. Then put it through it's paces.

It's always easier and faster to install a FD from square-one, than it is to make adjustments with it already attached. This tends to fix one thing - while throwing another out of kilter. Start fresh. You'll get it.

Adding a barrel-adjuster can solve many problems with the cable coming loose - or being too tight.

HillRider

One thought; any chance you have the fd mounted so far down that the cage is hitting one of the chainrings?

DannoXYZ 

I never even bother with the inner limit screw. I just let the lever-click/stop determine the inner position.