Trouble with rear cable pull ratio

[SidT]

Hello, I started with a sram nx 11 speed derailleur, cassette and shifter. The problem was I could not fine tune the indexing of the high gears without messing up the lower gears and vice versa, as if the shifter is pulling slightly too much cable per shift. Since then I have changed my cassette, derailleur, cage and pulley wheels to Garbaruk parts (the 11 speed hg cassette and sram 11speed cage). The problem was still there so I replaced my gear cable housing and cable first, no change, I replaced the derailleur hanger, no change, I have also tried 2 different shifters, firstly a sram apex, this made it worse but oppositely like not enough cable was being pulled per shift so I bought another different shifter, a sram gx thinking this might be more accurate but the problem is still there, lastly I replaced the derailleur for another sram nx but a brand new one thinking the parallelogram cage could have been bent but still the problem is there, its so annoying, I just want smooth gear changes, does anyone have any suggestions?

 

[BikeGremlin]

Hello, I started with a sram nx 11 speed derailleur, cassette and shifter. The problem was I could not fine tune the indexing of the high gears without messing up the lower gears and vice versa, as if the shifter is pulling slightly too much cable per shift. Since then I have changed my cassette, derailleur, cage and pulley wheels to Garbaruk parts (the 11 speed hg cassette and sram 11speed cage). The problem was still there so I replaced my gear cable housing and cable first, no change, I replaced the derailleur hanger, no change, I have also tried 2 different shifters, firstly a sram apex, this made it worse but oppositely like not enough cable was being pulled per shift so I bought another different shifter, a sram gx thinking this might be more accurate but the problem is still there, lastly I replaced the derailleur for another sram nx but a brand new one thinking the parallelogram cage could have been bent but still the problem is there, its so annoying, I just want smooth gear changes, does anyone have any suggestions?

Hi,

I can't see the bicycle and I don't know the exact models of components used, so I will make some assumptions - please correct me if I get something wrong.

Presuming you have matching (compatible) shifter, housing, cables, rear derailleur, cassette, and chain, this could still be preventing you from making the gears work:

Briefly put: you say you've replaced the hanger, so we can assume it is straight (though one measurement is better than a thousand expert opinions and is the only way to really confirm that). However, depending on how the cables and housing are routed, and how the cable is pinched to the rear derailleur, that could be causing the problem. For example, if you pinch the cable to the RD on the wrong side of the pinch bolt, or don't route it properly on the RD itself (before pinching, depending on the exact RD model), you could effectivelly alter the pull ratio. An example:

Apart from that, the problem could be cuased by the starting position. I often see the cable not being pulled tight before pinching, or the shifter not being set to the position to release all the cable ("1st," "slowest" gear in this case). So people do tuning with the system being off by one whole gear. Again, I'm making guesses and assumptions here as I can't see the bike.

Another problem could be the chainline. If the front chainline is too far off compared to the rear chainline, that could be causing the problem with some gears - especially if the chainstays are not 45 cm long (or longer).

Worn chain or cassette could also affect shifting.

Hope this helps at least a little bit and gives you some ideas.

Relja

 

[SidT]

Hi Relja, thanks for your reply, sorry this reply has taken this long.

Yes your reply definitely helps me some, no one else has mentioned the chainline before and mine is biased toward the high gear end of the cassette, quite extremely,

I have to be in gear 8 for the chain to look straight, the worst affected gears for my indexing problem are always 10 and 2.

I tried photographing the chainline but the camera on my phone wont focus.

I'm pretty sure I've got the cable attached to the right side of the bolt on the derailleur but here's a pic of that.

I have already centred my rear wheel in the frame by moving washers between the locknuts on the axle from one side to the other, it was way off centre when I got it,

I don't see any way of altering the chainline in the right direction from the crank end because there is only about a 4mm gap between the teeth of the chainring and the frame.

I've came to a compromise now and am putting up with rough sounding gears in gear 10 only, its not too bad, just a slight intermittent clicking or whatever you'd call that noise.

Thanks again for your help Relja.

 

[SidT]

I said the worst affected gears were 10 and 2 but i should have said 10 or 2 depending in how i set the barrel adjuster.

Im watching the video again now, cheers, Sid.

 

[SidT]

I forgot to mention, the chain is a brand new 12speed sram X01 and its a 1x 38 teeth chainring, I know its a 12 speed chain on an 11 speed system but I heard they work well and I saw a youtube vid where the guy is using pretty much all the same components I have and he has really smooth shifting.

 

[BikeGremlin]

I forgot to mention, the chain is a brand new 12speed sram X01 and its a 1x 38 teeth chainring, I know its a 12 speed chain on an 11 speed system but I heard they work well and I saw a youtube vid where the guy is using pretty much all the same components I have and he has really smooth shifting.

Yes, chains with more speeds generally work perfectly fine on systems with fewer speeds. I've even used some extremely different setups. For example: I've used a 10-speed chain with a 7-speed cassette and it was OK - though the inner width for 5~8 vs 9~12 speed chains is different, so I had expected problems. Using a 12-speed chain on an 11-speed drivetrain should be fine.
Note 1 (just in case):
The reverse is not good. I.e. you can't use chains for fewer speeds on cassettes with more speeds, as the chains' outer width is greater and they could get stuck and not shift properly.
Note 2:
The Note 1 does apply to cassettes, but it doesn't apply to derailleurs. I've used 9 and 10-speed derailleurs with 8-speed chains and had no problems whatsoever.

Having said all that, SRAM Eagle 12-speed chains may not play nicely with 11-speed cassettes according to SRAM. That could be causing the problems! Note that I haven't tried that combination so can't confirm it, but it is what I suspect and I'd try it with an 11-speed chain.

Relja

P.S.
I wrote this article - and will try to make it sticky on my website (I'll also try to make a sticky forum topic about that):
Bicycle repair or tuning – how to ask for advice?

It's not your fault, you couldn't have known, but in my experience, providing all the details (even those that might seem irrelevant) can make it easier to provide useful answers and help - i.e. to figure out what could be causing the problems (the 12-speed SRAM Eagle X01 chain in this case.

 

[SidT]

Yes, chains with more speeds generally work perfectly fine on systems with fewer speeds. I've even used some extremely different setups. For example: I've used a 10-speed chain with a 7-speed cassette and it was OK - though the inner width for 5~8 vs 9~12 speed chains is different, so I had expected problems. Using a 12-speed chain on an 11-speed drivetrain should be fine.
Note 1 (just in case):
The reverse is not good. I.e. you can't use chains for fewer speeds on cassettes with more speeds, as the chains' outer width is greater and they could get stuck and not shift properly.
Note 2:
The Note 1 does apply to cassettes, but it doesn't apply to derailleurs. I've used 9 and 10-speed derailleurs with 8-speed chains and had no problems whatsoever.

Having said all that, SRAM Eagle 12-speed chains may not play nicely with 11-speed cassettes according to SRAM. That could be causing the problems! Note that I haven't tried that combination so can't confirm it, but it is what I suspect and I'd try it with an 11-speed chain.

Relja

P.S.
I wrote this article - and will try to make it sticky on my website (I'll also try to make a sticky forum topic about that):
Bicycle repair or tuning – how to ask for advice?

It's not your fault, you couldn't have known, but in my experience, providing all the details (even those that might seem irrelevant) can make it easier to provide useful answers and help - i.e. to figure out what could be causing the problems (the 12-speed SRAM Eagle X01 chain in this case.

thanks Relja, i will definitely get an 11 speed chain and try it out, i will let you know what the results are, thanks again.