# Front derailleur limit screws, no effect



## Kimv (May 19, 2012)

They don't seem to be working. So I read the Park Tool guide but still. The front derailleur (SLX) started to rub a bit against the chain so I thought it was time for some readjustment. With the cable still connected I put the derailleur on the smallest blade and was unable to adjust it with the limiting screws. Although the cable had some slack, I then tried to adjust without the cable connected. Since I didn't have any luck, I then just fully screwed in and out the limit screw but no effect. I figured I might be playing with the wrong screw so I did the same with the other. The derailleur just remains in the inner most position, with the outer part of the cage against the chain on the smallest blade.

Bottom line: screwing in or out either limit screw with the cable disconnected has zero effect.

Am I doing something wrong?


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## DavyRay (Apr 13, 2012)

Kimv said:


> Am I doing something wrong?


Obviously, you are. Let's figure out what.

First step, since you are lost, leave the cable disconnected. Move the front derailleur cage out and in by hand. Does it line up with the chainrings at all? You will find that one limit screw will touch on the outermost position, and the other one touches on the innermost position.

Move it back and forth. Watch that work for a while. It will enlighten you.


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## Harold (Dec 23, 2003)

If you want to get a good idea what's going on, you need to find a good angle to see the ends of those limit screws and what they're touching (if anything). There should be little tabs that the screws push on to adjust the high/low limit.

Usually those limit screws are set-and-forget, at least while you're still using the same chain/cassette/chainrings. It sounds to me like you probably needed a cable tension adjustment, which can be done with the barrel adjuster at your shifter.

Derailer Adjustment


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## eb1888 (Jan 27, 2012)

Clean everything with a cloth and brake cleaner. Put your fingers of both hands behind the cage and your thumbs along the top face of the large ring and squeeze in and out checking for smoothness. Look at the two silver limit screws. One is above the other. Below the top one a little left is the letter "L". This top screw controls how far the derailleur cage swings toward the seat tube and affects chain alignment for the smallest ring. On mine it is screwed in quite a lot. The screw below it marked "H" controls how far out the cage swings when you have enough cable pull.
If the cage isn't swinging in close enough to the seat tube to guide the chain while on the small ring check for what it hits. It's a long cage and could hit the tire or chainstay.
Once you set it for the small ring put the cable on just loose to avoid over pulling for the center ring alignment. This is a little difficult to set exactly right and the barrel adjuster at your shifter is how you fine tune it. Then click up to the large ring and adjust the lower screw "H".


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## jeffj (Jan 13, 2004)

First of all, the cable adjustment adjusts the position of the (front) derailleur only when the chain is on the middle ring. On the inner and outer chainrings, it is the limit screws that position the cage. It is normal for the cable to be a little slack when the front derailleur is shifted to the inner chainring. On many front derailleurs, it is the screw that lies toward the outside of the derailleur that adjusts for the inner chainring, and vice-versa.

If you want to start over from scratch, this is the procedure I use for front derailleur adjustment:

Before starting, make sure the FD (front derailleur, specifically, the ‘cage’ of the derailleur) is aligned with the chainrings from front to back and that the height is set correctly so the chain 'cage' is at 2mm above the largest chainring when it is shifted to the #3 position. New front derailleurs come with a plastic spacer that holds the FD in the right spot so you can mount it correctly before you ever connect a cable. You can usually find something to stick in there to do the same thing. Once the FD is mounted correctly, remove this spacer and continue... If the derailleur is already mounted and has worked correctly in the past, you can skip this step and only refer back to it if you can't get it to work after the steps below.

1) Just as with the RD adjustment, turn the cable adjuster on the front shifter all the way in and then back it out one full turn.

2) Adjust the shifter to #1 on the shift control.

3) If the shift cable is connected, make sure the cable is not real tight (taut) at this point. You can check this anywhere the cable is exposed from the housing. If it is taut, loosen the cable hold-down nut and disconnect the cable.

4) Shift the rear derailleur so the chain is on the largest cog (1st gear). Using the limit screw that adjusts the lower limit (that keeps the chain from falling off the smallest chainring - this is usually the screw toward the outside of the derailleur, but not always), adjust it so the inside of the 'cage' barely touches the chain and then back it off just barely enough until it no longer touches the chain. 

5) Reconnect the front derailleur cable in the same manner as you did the rear one but with just a bit more slack. Not a lot, but it should feel just a bit 'loose'.

6) Place the shifter in the #2 position and turn the pedal cranks. If the chain does not shift to the middle ring, move the chain to it by hand.

7) Using the cable adjuster on the shifter, turn it one way or the other to move the cage so it just touches the chain and again the other way just far enough that it no longer touches the chain.

8 ) While turning the pedal cranks, shift the front derailleur to the #3 position. It should shift there on it's own. 

9) Shift the rear derailleur to 9th gear. If the shifter will not move to the number 9 position, turn the other limit screw (the one you didn't use earlier) until it will.

10) Making sure the chain is actually on the smallest cog on the rear cassette, use the same limit screw referred to in Step #8 to adjust the cage so it just touches the chain and then back it off just enough until it no longer touches the chain.

11) Hold up the rear of the bike (or put it in a stand if you have one). Turn the cranks and see if the bike shifts OK from the largest chainring to the middle chainring and back to the largest chainring. If it does, shift the rear derailleur to the largest rear cog and check to see if you can shift from the largest chainring (in front) to the middle chainring. 

If it does not shift from the largest chainring to the middle chainring, turn the cable adjuster on the shifter inward until it does. If you have left enough slack in the cable as instructed in Step #5, you shouldn't run out of adjustment room. If not, you may have to shift down to #1 position on the front shifter, turn the cable adjuster all the way in and then back out one full turn, loosen the nut, give the cable a bit more slack than you did before and return to the beginning of Step #11.

If it does not shift from the middle chainring up to the largest chainring, turn the cable adjuster outward (loosen) until it does (while turning the pedal cranks of course).

12) While turning the cranks, shift the FD to the #1 position. If it does not satisfactorily shift to the smallest chainring, use the limit screw used in Step #4 to move the cage over toward the frame until it will shift to the smallest chainring while turning the cranks. Do this adjustment in 1/8 turns of the screw or less. If you go too far, it may throw the chain too far resulting in the dreaded 'chainsuck'.

From here, you may need small fine tuning adjustments, but this should get you very close if not on the money. Good luck.


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## kikoraa (Jul 25, 2011)

Lbs


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## Kimv (May 19, 2012)

Thanks a lot all of you for taking the time to write up such useful answers. What helped me a lot was, like one of you suggested, to just look at the mechanism from an angle to see the working of the screws.

And I was able to get it right after applying your write ups! It's working great now


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## ghettocop (Jul 26, 2011)

Good job OP! it's great to be able to figure out and remedy problems on your own. Now you can tune your front mech thanks to the helpful members. Whats next?


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## Tone's (Nov 12, 2011)

jeffj said:


> First of all, the cable adjustment adjusts the position of the (front) derailleur only when the chain is on the middle ring. On the inner and outer chainrings, it is the limit screws that position the cage. It is normal for the cable to be a little slack when the front derailleur is shifted to the inner chainring. On many front derailleurs, it is the screw that lies toward the outside of the derailleur that adjusts for the inner chainring, and vice-versa.
> 
> If you want to start over from scratch, this is the procedure I use for front derailleur adjustment:
> 
> ...


Great post mate, nice work helpin the man out, cheers:thumbsup:


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## Kimv (May 19, 2012)

Actually I do have another issue but I made a new thread about it:

http://forums.mtbr.com/showthread.php?t=819043


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## chuzzwuzzer (Aug 21, 2013)

Just been following jeffj's advice after pulling my hair out trying to sort out my daughters specialized mtb gears. Got it all running smooth but to achieve this the front derailleurs barrel adjuster is extended almost fully out. Is this okay or does it mean i should have pulled more tension on the cable before reconnecting it in step 5 ?


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## eb1888 (Jan 27, 2012)

A little more tension and you will be in better shape for future adjustments.


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## Spetrie (Jun 17, 2014)

I know this thread is a little old but I was reading through as I'm adjusting my fd and discovered that the "l" limiter screw has been completely unscrewed and it will not go back in. I only bought the bike a week ago from a chap who said the gears needed some adjustment but he hadn't done it. Any suggestions! Thanks


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## AndrwSwitch (Nov 8, 2007)

Finding the threads can be tricky. I find I can sometimes feel where they start a little better if I twist the screw counterclockwise. It'll drop in fairly positively when I find where the female thread starts, and then I can screw it in as normal.

IIRC, the limit screws are screwed into a sheet metal piece. So if they're damaged, you could chase them with a tap.


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