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Two years ago I build a bike (flat bar) with SRAM 1x11. Around a month ago the rear-derailleur broke (guide pulley broke).

I bought a new rear derailleur: Shimano 105 RD-5800-GS.

After installation shifting got bad. The rear derailleur moves to far for each click, so sometimes it changes two gears for one click. It only takes 8 clicks to move the chain from the inner sprocket to the outer - and only 8 clicks to move it back. In other words it seems like the derailleur moves around 5 millimeters instead of 4 millimeters.

I have another bike (road bike) with Shimano 105 5800 group (2x11). I tried to take the wheel and the rear derailleur from that bike to the bike with the problem. It did not help - problem was the same.

I bought a new shifter: "Shimano XTR SL-M9000-R Rapidfire Plus Shifting Lever - 11-speed". Problem was still the same after installation. (Cable was also changed).

I bought and installed a new derailleur hanger. Problem is still the samme.

I have not had any crashes.

I think I have tried everything. Any ideas, what can I try ?

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    Why not simply buy a replacement pulley? – Carel Jul 11 '18 at 16:32
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So you originally had a have a SRAM 1x11 derailleur and matching shifter then swapped the rear derailleur for a Shimano 105.

That is your problem right there. Shimano derailleurs are not compatible with SRAM shifters. The length of cable the shifter pulls for each gear change is different between SRAM and Shimano (and between Shimano road and mountain groupsets at 10 speed and above). That's why the derailleur is moving the incorrect distance for each gear shift.

You need a SRAM derailleur that is compatible with your SRAM shifter. You can replace the guide wheels in all but the cheapest derailleurs, so you could fix your original SRAM derailleur and re-install that.

Or you could of course replace the shifter with one compatible with whichever Shimano derailleur you choose to run.

  • OK. I have not been happy with SRAM. So I want to change to Shimano. As I wrote I changed the shifter to Shimano. But I was not aware that Shimano 11-speed road and 11-speed MTB was not compatible. Thanks. – Cyclist_DK Jul 11 '18 at 14:09
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    This is a good resource if you want to look into it in detail: blog.artscyclery.com/science-behind-the-magic/…. – Argenti Apparatus Jul 11 '18 at 14:50
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Your derailleur and shifter are incompatible. Derailleur gears work by the shifter moving the gear cable in or out a certain distance (the "cable pull"), which causes a mechanical linkage in the derailleur to move the derailleur in or out a certain (different) distance (cable pull times "shift ratio"). Different companies' cassettes may also have the cogs at different physical spacing.

For example, suppose your cogs are 5mm apart. A very simple mechanism might just have the shifter pull the cable 5mm, which moves the derailleur 5mm, but a different system might have the shifter pull the cable only 2.5mm with the derailleur linkage doubling that.

  • You started with a SRAM derailleur and a compatible SRAM shifter, which worked.

  • You then had a Shimano 105 road bike derailleur, which isn't compatible with the SRAM shifter because it has a different shifting ratio so needs a different cable pull to move it the right distance.

  • You now have a Shimano 105 road bike derailleur attached to an Shimano XTR mountain bike shifter, which is still not giving the right cable pull for the derailleur's shifting ratio.

In short, pick a product line and stick to it.

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You can rock 11 speed mountain with 11 speed road. Check out these guys: https://www.wolftoothcomponents.com/collections/derailleur-optimization/products/tanpan .

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