Issues with switchi...
 

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[Closed] Issues with switching from 12sp SRAM to Shimano?

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I have NX shifter/mech on the current bike and was looking to move to SLX/XT shifter/mech, both 12 speed, but i have been having an absolute nightmare trying to get it to work, the cassette is a GX 12 speed, so should work with both set ups.

On switching over, i basically just removed the NX components, stuck the shimano on and set it up, the bike has internal cable routing and full outers, so was easy to switch, i did that, set the upper/lower limits, then the B screw and tried setting the gears, but it just failed to work, as it would jump two gears at a time, then reach the upper/lower ring with 3 or 4 gear pushes left.

No matter what i did this would invariably happen after one or two goes through the gears, after an hour or so i ended up sticking the NX back on, set it and it worked same as before, no issues of jumping gears, or lack of range for the shifter and so on.

What the hell is going on with this, never had an issue like this before, i checked the mech, tried it with the clutch on and off, checked the shifter, it is 12sp and has the full shifts, checked the outers were not impinging on the cable to cause any issues (as the NX and XT have an inch or so difference in the last outer length), etc, etc, etc.

Wish i could say there was an issue with the hanger, but it works with the NX, it's a cube stereo hybrid 160, so others in the range operate 12sp shimano.


 
Posted : 12/06/2020 12:45 pm
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Sounds like the cable isn't seated correctly in the shifter.


 
Posted : 12/06/2020 12:48 pm
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Technically there is a slight pull ratio and cassette spacing difference isn’t there between Sram and Shimano. From what I’ve read most people can get it working ok ish but not 100% perfect. Maybe the combination of mech hanger and that mismatch is doing for you.


 
Posted : 12/06/2020 12:51 pm
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The cable is in the mech properly, was one of the first things i checked due to the difference in length of the last outer, i wish it was the cassette, but so many folk get it working, i'd expect a slight harshness in one or two gears in the range, but not jumping as much as it is, it's as if the pull ratio is double, might give it a try with the NX shifter to see if it jumps just as much, i know it won't work, but if it's just slightly off and i get the full range then i guess it'll point to the shifter.


 
Posted : 12/06/2020 1:08 pm
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If you've got 3 or 4 shifts left and it's gone across the cassette, something has gone wrong somewhere.

Is the cable routing in the mech ok? Can you post a pic?


 
Posted : 12/06/2020 1:14 pm
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Yep, I agree, something has gone wrong somewhere. No doubt.


 
Posted : 12/06/2020 1:16 pm
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Any chance you've got the cable clamped incorrectly at the mech? Look at the dealer manual page 15


 
Posted : 12/06/2020 1:16 pm
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It shouldn't be that bad, as you say - even if it's going to be ropey, you should get the full range or very close to it.

The symptoms you have sound more like a hanger issue, but a standard hanger should work with both.

Edit - yes, post a pic from the side and behind.


 
Posted : 12/06/2020 1:20 pm
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Chain length is something to think about as well. Both SRAM and Shimano have slightly different ways of setting the correct chain length for their rear mechs.


 
Posted : 12/06/2020 1:24 pm
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On the subject of chain length, anyone gone from Eagle to Shimano and needed a longer chain? I'm looking at doing the same but if I need a new chain then may as well get a new Shimano cassette... And Microspline freehub.


 
Posted : 12/06/2020 1:35 pm
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When i can work up the enthusiasm i'll give it another shot, i checked that PDF, the cable is routed correctly, one of the good things i see with 12sp shimano as it works like a little pulley to get more tension or slacken off. The chain length is fine as well, i think it actually overlaps for me on both (5 links).

I was going to try the 12sp shimano on the other bike, but i appear to need a modified hanger for the XT mech!


 
Posted : 12/06/2020 1:47 pm
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Used exactly the same chain, cassette and chainrings when I went from SX to XT.

I did change the cable though...


 
Posted : 12/06/2020 1:51 pm
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I just switched over to the XT mech, yes slight jump on a couple of gears, but it shifts up with the NX mech through the gears, guess that's me sending this SLX shifter back!


 
Posted : 12/06/2020 2:07 pm
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Cheers, looking at XT shifter and SLX mech, anyone seen anything cheaper than Bike Discount: £44 for the shifter and £51 for the mech.

Sorry to take over your thread argee!


 
Posted : 12/06/2020 2:32 pm

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