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The front derailleur cable is as taut

cable is taut

as I can get it.

To attach the cable with as much tension, it's first necessary to understand the inside of the barrel adjuster.

And the H limit screw on a Sora FD is so undone (top red arrow)

H limit screw entirely unscrewed

it does not even touch its footing (bottom red arrow). (The yellow ball is removed.)

Yet when the chain is on the larger chainring and on any of the three smallest cogs, the chain rubs (red arrow)

chain rubs against FD cage

against the FD cage on the outside.

What else should I try?

If at this point I insert a tougher rubber ball to tighten the FD cable even further, the cage does get off the chain. Is that an indication that my best effort to pull the cable hard before tightening it was not good enough, and I should try pulling harder?

Components: Sora Sora R3000 front derailleur and ST-R3000-L shifter.

Update (question re "judgment" tool, following Nathan Knutson's answer):

The cable goes from one geometric point (bottom red arrow) on the bottom bracket to another geometric point (top red arrow) on the derailleur. There is no tweaking possible to the location of these two geometric points. What is, then, the purpose of the judgment tool?

cable taut between two points on bottom bracket and on derailleur

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    It's not entirely clear what you are asking, but you probably need to first set the shift lever in its lowest setting to slacken the cable, then screw in any barrel adjusters most of the way, the loosen the clamp securing the cable end to the derailer, pull on the end of the cable to pull some of the cable through the clamp, then re-tighten the clamp. – Daniel R Hicks May 1 '20 at 0:53
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    The way to determine if more cable pull will help is to pull on the cable. – Daniel R Hicks May 1 '20 at 1:07
  • @DanielRHicks Lol, okay, now I establish beyond any doubt that cable pull is indeed needed. If I get the ferrule off of the housing, I can tighten the cable appropriately, but I can't get the ferrule back. If I do not get the ferrule off the housing, I can't pull the cable enough. What's the recipe? – Sam May 1 '20 at 1:12
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    You're not making much sense. Which ferrule? – Daniel R Hicks May 1 '20 at 1:55
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    I hope this is obvious, but: Before you adjust the cable tension all the cable housing and cable housing end caps should be in place and firmly seated in their cable stops. You should only use the cable clamp and barrel adjuster to adjust cable tension. Photos would help a lot. – Michael May 1 '20 at 5:59
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I'm going to assume you've got FD-R3000 and are pairing with a compatible road double shifter.

The anchor position is adjustible. Follow the procedure in the Shimano dealer manual for your model. It is available at si.shimano.com. There are only two positions so if you don't have the special angle-finding tool you can use process of elimination. Failure to use the right position can cause what you're experiencing. The two different positions slightly alter the lateral point on the arm where the cable is anchored, which tunes the total throw.

All the "long-armed" Shimano road front derailleurs have the quirk of needing a ton of cable tension. The axiom with them is that once the right anchor position is chosen and assuming compatible parts, setup problems are almost always due to inadequate tension. They don't conform to generic instructions for FD setup. A good procedure is start with the shifter and barrel adjuster in the slackest position, then use pliers, a fourth hand tool, or the inner limit to pre-actuate the heck out of the FD as you pull the cable tight while anchoring the cable, then add some more tension as needed with the barrel adjuster after that.

You usually must accept essentially zero clearance between the chain and inner cage in the low gear with these derailleurs.

Another compounding factor to difficulty adjusting the "long arm" FDs is that the cable is anchored in a rather bent position with them, which can make it difficult to simply loosen the anchor bolt and pull out more slack - the memory of the material makes it want to return to how it was. You can try making a marking on the cable where it was exiting the anchor previously in order to be more sure you've actually added tension.

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  • I am following the Dealer's Manual of the Sora Sora R3000 FD, and I have indeed not yet ordered the converter judgment tool (TL-FDR30). Without having it in hand, I'm not even sure what this tool does. – Sam May 1 '20 at 20:29
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    I have the Sora groupset too. I ended up following the Shimano dealer manual. I don't have that judgment tool (I think it's just paper anyway). The way I see it, this tool is supposed to let you look at how the FD cable lines up as it approaches the FD from below. Depending on the frame it could vary a bit. Depending on where the cable is, the 'converter' goes either ON or OFF, which I think has some effect on the leverage of the cable attachment point – user39927 May 1 '20 at 21:44
  • I can confirm that my adjustment of FD-R3000 did involve pliers (and a lot of swearing at first) as well. The barrel was not of much use. On my main Claris bike the barrell adjuster is enough but the bike came better set-up in the first place, because it was sold in a shop. – Vladimir F May 1 '20 at 22:54
  • @NathanKnutson Somehow I already started fancying myself having some understanding of what's going on and decided to write an answer (bicycles.stackexchange.com/a/67768/48599). The picture and explanation there show the steps needed before the cable can be attached with sufficient tension. Could you read my answer and critique it? Is that indeed what I should be doing? – Sam May 2 '20 at 0:38
  • @Sam That all seems right in terms of how to prepare and use an inline barrel adjuster. Your addendum to the question suggests you may not have the cable routed through the anchor area correctly if you're unclear how adjusting the position changes the geometry. The DM document shows this pretty clearly so I suggest double checking you have it routed around the notch correctly, as that will cause problems if it's wrong. – Nathan Knutson May 2 '20 at 0:46
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First you should check your derailleur cage is parallel with the chainring, an angled cage cause rubbing.

Nowhere in your question have to mentioned the front derailleur cable barrel adjuster. You mention a Sora groupset so this is a road bike. The barrel adjuster will be on a doentube frame cable housing stop, or perhaps in-line in the housing something like this:

enter image description here

if the lower limit is set correctly, you shoud be able to shift to the small ring, detach the cable, wind the barrel adjuster in (lengthens the cable relative to the housing), then re-attach the cable, pulling it reasonably tight. The cable can then be shortened relative to the housing (made more taught) be winding out the barrel adjuster. This will move the derailleur cage outward.

Pulling harder on the cable isn't going to make it any tighter - it's made of steel and expressly designed to not stretch afterall.

Try watching the Park Tool Front Derailleur Adjustment video on this page, if you work through their step by step procedure you should be sucessful.

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    I like the production value of the video you point to very much, and I watched it multiple times, but I'm still puzzled that the critical step of pulling and tightening the cable is glossed over. Could it be that this particular step is too different between models. The particular model I have requires an extra "judgment" tool, which is apparently just cardboard (since it can be bent). – Sam May 1 '20 at 20:31
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(This answer would not have been possible without the answers of Nathan Knutson and Argenti Apparatus.)

(I'm still not certain that this is the correct issue, but I had been wrestling with this adjustment for some time, and the issue has now evaporated once I used the solution below.)

An appropriate setting of the H limit screw is impossible if the barrel adjuster is malfunctioning.

It is not malfunctioning with a capital M, just a minor malfunction.

It's hard to see that that's the issue if one is just looking right/left/above/below the front derailleur.

If you have trouble setting the H limit screw, make sure that you are actually able to add tension in the FD cable through the barrel adjustment.

This answer shows the parts inside the barrel. It's an elementary device. But you may have the illusion that you are adding tension if the cable housing slips/glides on the metal part. The cause could be arbitrary (a tiny bit of oil, ..). Importantly, these two parts are designed to slip on each other. Again, as the answer there mentions, if the two parts do not slip against each other, the user could apply extra force and either keep adding undue torsion on the cable housing, or else simply strip the thread.

Disassemble, wipe any possible dirt/oil. Now make sure (visually) that the metal part does indeed start to protrude when you expect it to.

Now I'm very curious, is deception from a barrel adjuster a common problem? We're no longer in Q&A mode but in fireside chat mode. Add a comment or suggest an alternative medium.

Why? / Illustration:

Perhaps a diagram illustrates the issue better.

barrel adjuster

The center line is the cable. We're no longer talking specifically about the FD cable, only about cables with barrel adjusters in their middle, not an edge.

A and D are the cable housing. Notice that at all times the cable is under tension, but the cable housing is under compression. For derailleurs, the amount of tension/compression depends on the cog or chainring chosen. The bigger the cog/chainring, the bigger the tension.

C is the barrel adjuster. That's the part you grip. It has female threads. B is the part with the male threads. When B and C are fully threaded, the user cannot even see part B. B disappears inside C.

Here is the important part: this assembly works by ensuring that there is less friction on the threads (between B and C) than between A and B as well as between C and D.

When you turn the barrel adjuster, the relatively high friction between A/D (plastic) and B/C (metal) is what allows you to add or remove tension.

If any grit made its way into the B-C joint, or if any grease made its way to the A-B or to the C-D joint, the entire set-up will no longer work.

It is always prudent to clean the A-B and the C-D joint. No oil should be there. You want as much friction as plastic-against-metal will allow. (If you're following and want to make sure you never strip the threads, you do not want to add a drop of glue in there! The design includes slippage.)

I'm not so sure whether it's prudent, if you suspect that the B-C joint is somewhat rough, to add a drop of oil or a hint of grease. Adding grease there may invite an unwanted turn, either accidentally or from the repeated vibration when riding.

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  • Good catch and diagnosis! Barrel adjusters can get a bit sticky as you have found, though normally functional on a new bike (bad luck). The two parts need to slip against each other to thread/unthread, but then one end at least needs to grip the housing ferrule to remain still while you turn the other. It can be a problem, yes, though with more practise you will be observing the barrel adjuster while you turn it, to gauge how much tension you are adding. if it doesn't extend then you know it needs a little cleaning or exercise. If the top is poking out you might be able to grip it just enough. – Swifty May 2 '20 at 7:24
  • @Swifty (I'm just so proud I can now understand barrel adjusters! :^-). More seriously, as usual a Q&A triggers a Q, this time in the last paragraph. – Sam May 2 '20 at 8:04
  • I have used both grease and oil on barrel adjusters, depending on what is at hand. Oil will get it moving but not last as long, grease will reduce friction and stick around to protect the threads. No issue around the adjuster moving when you don't want it to, it's held/compressed together by all of that cable tension anyway – Swifty May 2 '20 at 8:15
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    that's cool. It's better asked as a question if you have it, then you get more input than just my own waffle Nevermind the sacrilege of follow on questions in comments (naughty us). love the diagram btw – Swifty May 2 '20 at 8:31
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    My theory is that if the friction at A-B is lower than at B-C, then when you turn C, B turns with it, and there is no adjustment possible. We want A-B to hold, so that when we turn C, they move away from (or toward) it. Reducing the friction at B-C makes A-B relatively more grippy. I'm putting this here to try and not influence the new question too much but explain why I think the above – Swifty May 2 '20 at 10:12

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