Chain jump on smallest cog, why?
#26
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#27
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The wipperman quick link will skip on the smallest cogs if it is installed upside down
#28
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#29
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#30
Senior Member
Thread Starter
Thanks, I just check, and it seems mine is somewhat sticky too. I'll lube it as instructed in the video.
#31
Senior Member
Thread Starter
Ok, so I added another spacer on the drive side of the bottom bracket shell......didn't work. Chain still skips in the smallest cog. Shifting otherwise is great.
Could it be the free hub? I read somewhere that skipping in the small cog is the first sign of the free hub going, and eventually it'll skip in the other cogs. How would one test for that?
Could it be the free hub? I read somewhere that skipping in the small cog is the first sign of the free hub going, and eventually it'll skip in the other cogs. How would one test for that?
#32
Senior Member
Thread Starter
Ok, swinging back. After talking to a few people, I was convinced to check the hanger....I talked myself into adding to my tool chest. The Park DAG-3 arrived yesterday, and guess what? The hanger was indeed bent. At the probe end, I'd estimate it was out about 10-12mm. So I bent it back. It was quite easy. I reindexed the gears, and I'll check it out on my ride tomorrow. It occurs to me that this might not solve the problem, but at least I am narrowing the possibilities as I go.
#33
Full Member
Bent hanger would have caused poor shifting or autoshifting. Some people refer to autoshifting as "jumping" as well, which is why forum participants often thoughtlessly copy-paste advice about "bent hangers" into every thread about chain jumping. You stated yourself that your shifting works perfectly fine. (It is strange though that you managed to obtain good shifting with a bent hanger...)
But anyway, you are describing a completely different issue, i.e. chain jumping forward over the teeth of the same cog. This is unlikely to be caused by a bent hanger. This is usually a chain wear/cog wear issue.
But anyway, you are describing a completely different issue, i.e. chain jumping forward over the teeth of the same cog. This is unlikely to be caused by a bent hanger. This is usually a chain wear/cog wear issue.
#34
Senior Member
Thread Starter
Bent hanger would have caused poor shifting or autoshifting. Some people refer to autoshifting as "jumping" as well, which is why forum participants often thoughtlessly copy-paste advice about "bent hangers" into every thread about chain jumping. You stated yourself that your shifting works perfectly fine. (It is strange though that you managed to obtain good shifting with a bent hanger...)
But anyway, you are describing a completely different issue, i.e. chain jumping forward over the teeth of the same cog. This is unlikely to be caused by a bent hanger. This is usually a chain wear/cog wear issue.
But anyway, you are describing a completely different issue, i.e. chain jumping forward over the teeth of the same cog. This is unlikely to be caused by a bent hanger. This is usually a chain wear/cog wear issue.
Here's another thing that occurred to me. Yes, the bike used to shift fine. I injured by arm, (ruptured distal tendon) and didn't ride the bike again for 6 months. I rode the indoor trainer. So, what could have happened to the bike just sitting in my basement for six months? I have a dehumidifier, so that's not the issue. Lube dried up? Maybe in the cable? I don't know,
#35
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This is common with crazy groupsets like 1x11, and almost all of the time is that something is bent out of original alignment.
You don't need brute force or an accident to misalign a RD, sometimes a bump on a doorway can do that.
A LBS will fix it 100% with their Park Tool DAG-2.2 .
Me, I just eyeball it and get it right most of the time.
You don't need brute force or an accident to misalign a RD, sometimes a bump on a doorway can do that.
A LBS will fix it 100% with their Park Tool DAG-2.2 .
Me, I just eyeball it and get it right most of the time.

#36
Senior Member
Thread Starter
This is common with crazy groupsets like 1x11, and almost all of the time is that something is bent out of original alignment.
You don't need brute force or an accident to misalign a RD, sometimes a bump on a doorway can do that.
A LBS will fix it 100% with their Park Tool DAG-2.2 .
Me, I just eyeball it and get it right most of the time.
You don't need brute force or an accident to misalign a RD, sometimes a bump on a doorway can do that.
A LBS will fix it 100% with their Park Tool DAG-2.2 .
Me, I just eyeball it and get it right most of the time.
#37
Mechanic/Tourist
I just came across your post, but this is a clear tipoff to a bent hanger (or twisted derailleur pulley): "If I adjust the barrel too far to get the 2 to 3 good, I sometimes have a problem with the 9 to 10. There's a very narrow range for getting both good." I'm glad someone finally convinced you to check. As for the skipping, I do not see anywhere what combo your high gear is. If you are consistently riding a high ratio combo at low rpm and high pedal pressure under the conditions you describe you certainly could have worn it in 800 miles.
Last edited by cny-bikeman; 06-03-23 at 06:48 AM.
#38
Senior Member
Thread Starter
I just came across your post, but this is a clear tipoff to a bent hanger (or twisted derailleur pulley): "If I adjust the barrel too far to get the 2 to 3 good, I sometimes have a problem with the 9 to 10. There's a very narrow range for getting both good." I'm glad someone finally convinced you to check. As for the skipping, I do not see anywhere what combo your high gear is. If you are consistently riding a high ratio combo at low rpm and high pedal pressure under the conditions you describe you certainly could have worn it in 800 miles.
I bought a new XT derailleur, standard length cage. Got a great price on it. I'm going to install it and a new hanger to see if it fixes the problem. I'll use the old derailleur to learn how to clean and service a derailleur.
#39
Mechanic/Tourist
Well, I asked about the "combo" of your high gear, meaning front/rear. I assumed the rear was 11, as that is the idiotic industry standard. Assuming you have only a 50t chainring, a very modest 70 rpm would mean you should be going at least 25mph before engaging high gear.
Given the symptom of still having noise in one gear after dropout alignment, I think trying a different derailleur is not a bad idea. It's more rare but not unheard of to have a derailleur get twisted at the pulleys, which has the same effect as a badly aligned hanger. I'm looking forward to see if that change helps.
Given the symptom of still having noise in one gear after dropout alignment, I think trying a different derailleur is not a bad idea. It's more rare but not unheard of to have a derailleur get twisted at the pulleys, which has the same effect as a badly aligned hanger. I'm looking forward to see if that change helps.
#40
Senior Member
Thread Starter
Well, I asked about the "combo" of your high gear, meaning front/rear. I assumed the rear was 11, as that is the idiotic industry standard. Assuming you have only a 50t chainring, a very modest 70 rpm would mean you should be going at least 25mph before engaging high gear.
Given the symptom of still having noise in one gear after dropout alignment, I think trying a different derailleur is not a bad idea. It's more rare but not unheard of to have a derailleur get twisted at the pulleys, which has the same effect as a badly aligned hanger. I'm looking forward to see if that change helps.
Given the symptom of still having noise in one gear after dropout alignment, I think trying a different derailleur is not a bad idea. It's more rare but not unheard of to have a derailleur get twisted at the pulleys, which has the same effect as a badly aligned hanger. I'm looking forward to see if that change helps.
#41
Mechanic/Tourist
Thanks, I suspected you had a small chainring, but did not have the information. But even with a 38t one should be going about 20mph to use it.
#42
Senior Member
Thread Starter
More headaches. So i went and bought a new derailleur. Instead of getting the same long cage, I got the regular cage of the XT8000 Deore, since the spec says it's good for up to 46 teeth, (which I have) and I read that the regular cage might give more precise shifting.
So I installed it today, then proceeded to index the gears. On the stand, everything seems ok EXCEPT the low gear, the 46t largest cog. It's making noise, which I isolated to the lower jockey wheel. The chain seems to be coming into the jockey wheel just very slightly too far towards the outside (away from the wheel), and the noise is the jockey wheel teeth hitting the chain just very slightly off center and then sliding into place. Second gear seems ok.
So first thing I do is play with the L screw again, slowly adjust the derailleur to move it to the outside, all the while checking how the jockey wheel and chain are playing together. Didn't work. I adjusted L screw even as far as the chain popping off the 46t to the next biggest cog, and at no point did the jockey wheel mate properly with the chain. It looks to me like the chain line angle is too extreme. I don't know what else it could be. I previously straightened the hanger with the Shimano Jag3.
I bought the bike like 6 years ago from a guy who had it built up from a frame kit. Some things that he did non-standard was use one spacer on the drive side of the bottom bracket (Shimano specifies 2, so I added another), and he used that long cage, when the regular cage is supposed to be sufficient.
I do know the dropouts are just very slightly off kilter. The tire does sit maybe a millimeter or two cocked in the frame, and at one point a few years ago, I borrowed a friend's Park dropout alignment tool and verified. So I'm wondering whether the builder used the one spacer and the long cage because of the misaligned dropouts. The long cage would push the jockey wheel slightly back, effectively lowering the angle of the chain.
This is very frustrating. I guess the only thing I can do is bring the bike back to the original layout, ( a new long cage and the one spacer) and go from there. Unless someone here has a idea. I wanted to ride tomorrow, so I'll put the old long-cage derailleur back on.
So I installed it today, then proceeded to index the gears. On the stand, everything seems ok EXCEPT the low gear, the 46t largest cog. It's making noise, which I isolated to the lower jockey wheel. The chain seems to be coming into the jockey wheel just very slightly too far towards the outside (away from the wheel), and the noise is the jockey wheel teeth hitting the chain just very slightly off center and then sliding into place. Second gear seems ok.
So first thing I do is play with the L screw again, slowly adjust the derailleur to move it to the outside, all the while checking how the jockey wheel and chain are playing together. Didn't work. I adjusted L screw even as far as the chain popping off the 46t to the next biggest cog, and at no point did the jockey wheel mate properly with the chain. It looks to me like the chain line angle is too extreme. I don't know what else it could be. I previously straightened the hanger with the Shimano Jag3.
I bought the bike like 6 years ago from a guy who had it built up from a frame kit. Some things that he did non-standard was use one spacer on the drive side of the bottom bracket (Shimano specifies 2, so I added another), and he used that long cage, when the regular cage is supposed to be sufficient.
I do know the dropouts are just very slightly off kilter. The tire does sit maybe a millimeter or two cocked in the frame, and at one point a few years ago, I borrowed a friend's Park dropout alignment tool and verified. So I'm wondering whether the builder used the one spacer and the long cage because of the misaligned dropouts. The long cage would push the jockey wheel slightly back, effectively lowering the angle of the chain.
This is very frustrating. I guess the only thing I can do is bring the bike back to the original layout, ( a new long cage and the one spacer) and go from there. Unless someone here has a idea. I wanted to ride tomorrow, so I'll put the old long-cage derailleur back on.
#43
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so the frame is bent? bummer.
And for the record.. i align the chain line and get fairly even crank arm clearances related to the chain stays of the frame, and don't care about what shimano says about what spacers need to go where, on a bottom bracket..... and i set chain Length with the "Small-Small" method to ensure less issues with lower roller noise and less drag at max tension too.
"Small-Small" is set with the roller cage hanging just below the "Horizontal" position... How does you roller cage look in Small-Small? did you change chain link count when you put the new derailleur on?
also, without reading through 40-odd posts.. Have You checked the Rear Wheel DISH yet? i've seen where people Reset a Wheel's dish to "Fix" a BENT FRAME more than once... and even Brand New Bikes with UNEVENLY Cut Dropouts that had the wheels dished off center too... it's usually the FRONT wheels, in those cases, but I did a rear wheel re-dish and frame mod last fall... a Vilano Box store bike... and one of the badly cut forks was also on a Vilano..
And for the record.. i align the chain line and get fairly even crank arm clearances related to the chain stays of the frame, and don't care about what shimano says about what spacers need to go where, on a bottom bracket..... and i set chain Length with the "Small-Small" method to ensure less issues with lower roller noise and less drag at max tension too.

also, without reading through 40-odd posts.. Have You checked the Rear Wheel DISH yet? i've seen where people Reset a Wheel's dish to "Fix" a BENT FRAME more than once... and even Brand New Bikes with UNEVENLY Cut Dropouts that had the wheels dished off center too... it's usually the FRONT wheels, in those cases, but I did a rear wheel re-dish and frame mod last fall... a Vilano Box store bike... and one of the badly cut forks was also on a Vilano..
Last edited by maddog34; 06-12-23 at 09:45 PM.
#44
Senior Member
Thread Starter
so the frame is bent? bummer.
And for the record.. i align the chain line and get fairly even crank arm clearances related to the chain stays of the frame, and don't care about what shimano says about what spacers need to go where, on a bottom bracket..... and i set chain Length with the "Small-Small" method to ensure less issues with lower roller noise and less drag at max tension too.
"Small-Small" is set with the roller cage hanging just below the "Horizontal" position... How does you roller cage look in Small-Small? did you change chain link count when you put the new derailleur on?
And for the record.. i align the chain line and get fairly even crank arm clearances related to the chain stays of the frame, and don't care about what shimano says about what spacers need to go where, on a bottom bracket..... and i set chain Length with the "Small-Small" method to ensure less issues with lower roller noise and less drag at max tension too.

I sized the chain using Park's Big-Big. I cant check at the moment using small-small, as my chain is hanging from a nail...I just waxed it. Tonight I did compare the chain length to two old chains that used to work fine. All three are the same number of links.
I just put the old derailleur back on, the long cage. As expected, it's shifting fine on the stand. I'll go out riding tomorrow, and full well expect the chain to continue jumping on the small cog. Then I'll adjust the barrel and try and see what happening.
#45
Senior Member
Thread Starter
i should correct the use of the word "bent", which implies it was fine and then something bent it. The dropouts are not 100% square to one another, and I suspect the frame was made that way, misaligned. I doubt the frame was bent after manufacture.
#46
Senior Member
Thread Starter
Wonder of wonders! I took the bike for a ride today, and the couple of times I shifted into the small cog, the chain didn't skip. I was bearing down pretty hard, and still no skip. I was only in that gear for about 30 seconds, but every other time I could get it to skip within 5 or 6 seconds. I'll take it out again to be sure. So what did I do? Not a hecka of a lot. I removed the old derailleur and then put it back on, torquing it down properly. I installed a brand new hanger, and used the JAG3 to straighten it.The old hanger seemed fine, and although I had already straightened it, I just felt like putting a new one on, I also indexed the gears a little differently. I started by removing the cable, and adjusting the H setting with the chain on and pedaling on the stand. Then I attached the cable, trying to be sure that it was taut. I also tried to follow Park's guide to indexing....chain on second smallest cog (#2), adjusting the barrel until the chain rubs on #3, then lowing tension by turning the barrel a quarter turn clockwise.
I find it hard to believe the indexing method had any effect. It shifted just fine before.....on the stand. Maybe I worked a little grit off the cable, in the housing?
I find it hard to believe the indexing method had any effect. It shifted just fine before.....on the stand. Maybe I worked a little grit off the cable, in the housing?
#47
Senior Member
Thread Starter
Swinging back. It started to skip again, but now I think it's completely fixed. 11T cog is working fine now. I installed a new long cage XT8000 derailleur, and at the same time, replaced the cable. Not the housing, but just the cable. I also reindexed in a different way, similar to what Park shows in its video.