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I was having issues with indexing my Shimano 105 R7000 RD previously. Basically, even after aligning the rear derailleur hanger as accurately as possible and changing cables, I noticed that, the acceptable indexing range seems to shift as I shift up. In other words, while the RD appears to be aligned with a particular sprocket, I will need to adjust the barrel adjuster either clockwise or anti-clockwise as I shift to different gears, and as a result, I end up with only 1 or 2 barrel adjuster positions where the indexing seems aligned across all gears.

I get that if an RD hanger is mis-aligned, this would be the expected behaviour since the RD would be at an angle to the sprockets. But in my case where the RD hanger is already aligned, what could be causing this behaviour? I was under the impression that each click of the shifter will move the RD by the same distance, and the distance between each sprocket is identical, and hence the acceptable indexing range should be consistent across all gears. By the way, I had swapped cassettes (all are Shimano 105 CS-R7000 series cassettes so no incompatibility issues there) and RD and the symptoms remain the same.

I also noticed from the Park Tools video that Calvin Jones had to turn the barrel adjuster as he moved up the gear range.

Does anyone experience this too when indexing their bikes and any idea what could be the possible reason?

3 Answers 3

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There are a few possible reasons:

  • Too much friction in your cables. The derailleur spring is very weak in the high gear (small sprocket) position and can have trouble pulling in cable. The biggest symptom is usually that it refuses to shift to the smallest sprocket or you have to make the cable very slack (which creates problems when shifting to the larger sprockets).
  • Bent derailleur hanger or bent derailleur. Sometimes not obvious, especially when it’s twisted instead of bent. There are tools to check this.
  • Incorrectly clamped cable at the derailleur. If you clamp it at the wrong side of the screw it changes the lever ratio.
  • Your cables stretch under tension or your housing compresses under tension. Maybe you’ve used brake cable housing? Maybe it’s broken somewhere? Never hurts to check thoroughly. Maybe the routing along the handlebar is bad (moves under load)?
  • Incompatible components, but I assume you’ve ruled that out and are using R7000 shifter and rear derailleur?
  • B screw in too much. Usually the biggest symptom is that it refuses to shift to the biggest sprockets because the chain/jockey wheel hits the sprockets from below.
  • Edit: One more: Loose cassette or incorrect spacers between sprockets. This can lead to an inconsistent sprocket spacing.
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    Referring to @Michaels comment on binding it can also occur within the derailleur linkage binding due to the presence of dirt or lack of lubrication.
    – mikes
    Commented Sep 12, 2021 at 16:40
  • Can add bent derailleur parallelogram to the list.
    – mattnz
    Commented Sep 12, 2021 at 20:22
  • Thank you. I aligned using the hanger tool to within 0.5mm of error (well or at least as best I can get it on all four sides). As part of my experiment, I even tried misaligning the hanger by pulling it outwards a little and it seemed to make things a little more consistent (albeit more noisy in all gears...). I thought it was the parallelogram too or perhaps the shifter so I changed to a new derailleur and shifter but didn't fix the issue. I am using 105 r7000 with Shimano sl-rs700 shifters.
    – trenz
    Commented Sep 13, 2021 at 0:11
  • B tension also didn't help in my case and I've tried both directions. Pretty much I've tried everything except changing the frame..I even tried a new wheelset with the same symptoms. I am using Shimano OP41 cable housing and also tried jagwire pros. I have changed the cables and housing at least five times... Trying short and long routing... But didn't seem to help. I have clamped the cable correctly, although I had to bend the cable after the bolt to avoid the cable hitting the spokes. I don't think that causes the issue, could it?
    – trenz
    Commented Sep 13, 2021 at 0:13
  • Wow, that sounds like a frustrating and expensive adventure. I’m all for DIY but maybe it’s time you visited a bike shop. Alternatively: Show us some good photos of the rear derailleur (in the lowest gear, highest gear, some middle gear) from behind and from the side, also details of the cable routing (btw: which housing end caps are you using?), shifter and some overview photos of whole bike, the handlebar and bottom bracket areas. Maybe it’s something obvious …
    – Michael
    Commented Sep 13, 2021 at 6:20
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One adjustment should cover the full gear range.

One possible reason is that you have installed the shifting cable incorrectly. If the cable is clamped to a different point, the amount that the derailleur moves when shifter moves the cable changes and the adjustment goes wrong.

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  • Thank you! I have routed the cable as per the instruction manual. However, because of the shadow RD design, I have to sort of bend the cable after the clamp bolt as the cable would go to the spokes otherwise. Would that be the cause of the issue? I didn't think so because whatever happens after the clamp should not matter?
    – trenz
    Commented Sep 13, 2021 at 0:10
  • Sorry, no idea, I've never adjusteda Shadow derailleur. Needing to bend the cable sounds a bit odd to me.
    – ojs
    Commented Sep 13, 2021 at 6:19
  • @trenz Yea, after the clamp is no issue.
    – MaplePanda
    Commented Sep 13, 2021 at 7:06
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Various errors in alignment accumulate as you shift through the gears. If you index on only one sprocket, you can do this quite easily with a wide range of adjustment but as you move further away from your selected candidate, the accumulated error becomes larger. Hence, any indexing adjustment contains a small amount of compromise that allows all gears to be selected as smoothly as possible without spoiling the other gears.

An extreme example can be the newer low-range Shimano 9-speed systems that can be almost impossible to index acceptably after some use due to the weak spring in the derailleur, the small amount of cable movement per click and error introduced by wear and contamination in the system.

The 11 sp system you mention uses a larger amount of cable per click to allow easier adjustment. With so many variables at play and increasingly narrow chains and sprocket spacing, a small error can be magnified into a large error in just a few shifts. The same principle applies when you are laying tiles, patio slabs or flooring; if you ignore a small error at the beginning it is likely to ruin things further up the line. Cf butterfly effect.

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  • Thank you. I guess this makes sense. The frustrating thing is I've already run down the list of possible errors and tried to address them individually but I can't seem to figure out what causes the error in the first place.
    – trenz
    Commented Sep 13, 2021 at 0:17
  • Which low-range 9-speed systems do you have in mind? Commented Sep 13, 2021 at 8:42
  • @VladimirF anything 9-speed in the shadow design, I have decided today after seeing an SLX that's so inaccurate it can be almost 2 gears out either way. We used to replace the Alivio 9-speed shadows with traditional shape Aceras for better performance when they started getting like this.
    – Noise
    Commented Sep 27, 2021 at 16:21

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