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I've outfitted my 2016 Giant TCX with a 1x 42t in the front and 11-40 in the rear. I'm finding that with the clutch engaged shifting into the 40t in the back is "harder" and it feels like there is resistance when I pedal the bike in the work stand.

The issue goes away if I disable the clutch. Tuning the clutch down slightly has helped with the shifting but my question is do I have too much tension and is my chain too short?

I followed these instructions and have posted an image below for reference the chain is cut to 57 links based on Park Tools equation and measurements based on this manual.

Thanks!

enter image description here

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    can you post a photo of the derailleur with the chain on the smallest cog? It could be that the chain isn't too short but not as long as it could be. – mikes Aug 19 '20 at 14:36
  • @mikes here is a link to the chain in the smallest cog photos.app.goo.gl/yXwSgqwzBjwbagbv8 thanks! – Matt Solomon Aug 19 '20 at 14:40
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    @MattSolomon You could definitely go a full link longer. On the backside of the derailleur cage there should be a Torx 30 shaped hole. ~5Nm should be roughly correct. Ultimately, it will feel less smooth than with the clutch off due to the higher tension. – MaplePanda Aug 19 '20 at 18:58
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Shimano 1x groupset manuals differ in chain length instructions from the general procedure that Park Tool provides in their repair help - the Shimano instructions say to add more additional links. That makes sense as in a 1x setup a derailleur needs to deal with less sprocket/chainring teeth difference than a 2x or 3x.

Looks like your chain is a bit too short, and that might be causing the issue. AFAIK, chain length should not affect tension very much. Derailleur springs are designed so that they deliver reasonably contant-ish tension over the range of movement of the derailleur linkages. You may be bumping up against the limits of the derailleur though.

I'd fix the chain length i.e. size it according to Shimano's instructions. That will either fix the issue or rule that out as a cause.

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  • Thanks Argenti! I will likely try a new chain this evening. To clarify, this is the manual I was referencing and followed for chain sizing si.shimano.com/pdfs/dm/DM-MARD001-02-ENG.pdf it also lined up with the calculation from Park Tool. Is there a different manual I should be referencing for set up? – Matt Solomon Aug 19 '20 at 17:14
  • @MattSolomon that's the right manual. What Park Tool 'calculation' are you taking about? Their general guide says minimum chain length around largest sprockets plus 2 rivets. Shimano says + 4 or 5 rivets AND a quick link. – Argenti Apparatus Aug 19 '20 at 17:21
  • thanks for following up. I'm talking about section 6 in that guide. My process was to install using the Shimano guide and then I checked it using that equation to verify the length is correct. Maybe I counted the rivets incorrectly and it just happened to work out with the equation. – Matt Solomon Aug 19 '20 at 17:33
  • Thanks for your feedback I took it to the shop I bought the chain from and they checked the sizing and said based on the manual it was correct. They adjusted the b screw, the low limit screw, and cable tension slightly. I went fo a ride this morning and it felt a lot smoother. Per other's recommendations, however, I'll likely swap the chain add 2 links and see if that leaves too much slack and work my way back. The chain that is on there now will fit on my road bike so it will be recycled properly. – Matt Solomon Aug 20 '20 at 18:43

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