Did I measure the chain a link too long? (More photos in comments. Basically the bottom sprocket doesn’t seem to be in line with the chain anymore and that’s causing the skipping? Like the sprocket is trying to run outside the chain?).
Change my chain as the old one was worn out. Everything worked fine before but now it’s jumping on this cog?
byu/Archaicarc inbikewrench
by Archaicarc
36 Comments
That jockey wheel could probably use replacing as well, although I’m not sure if that’s the cause or the issue here
The cog is probably worn out.
i think we need to see front chainring too to determine if that is worn.
>Did I measure the chain a link too long?
That would have zero to do with what we see in the video.
Maybe it’s cross-chained. Maybe that wheel is worn. Dunno. But it’s not caused by chain length.
I only replace the chain every 5,000 miles,
so also replace the derailleur, cassette and chain ring at the same time.
Even with all new cogs throughout, the chain runs a little rough for a week
or so until it settles in, just make sure it’s well-lubed…
https://preview.redd.it/vbavxu2u2xzg1.jpeg?width=3024&format=pjpg&auto=webp&s=905589b1e8aa9774aef56a922d34bb4f21316f3e
This is the issue the chain is trying to run on the inside of sprocket. Now sure what’s the cause…?
the quick link is backwards, the little not h in the center should point in the direction of chain travel.
Definitely rear derailleur related. Back out all the adjustment screws…check the “straightness” of the derailleur cage…check where the derailleur is connected to the bi k e and also that the chain is not installed incorrectly eg. Over the jockey wheel closest to the cassette, but behind the little tab below that then around the lower jockey wheel.
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The jokey wheel teeth seem to land on the side of the chain. Is it a proper chain for this transmission in terms of how many speeds? Is the jockey wheel tightened (check for side-to-side wobble). The wheel also might be worn out, so the teeh height is too low and the area it engages with the chain is two wide.
I’d start with replacing the jockey wheels. If they are really that worn out, your cassette and chainring likely need replacement, too.
You know where would be problem? I did this last week… The chain is not properly between The wheels.. There is link hitting The iron (preventing your chain to fall). Can you take photo from behind ?
That jockey wheel is bald my friend
Check bearings. In my case that was the cause
If you waited too long on the old chain it’s likely your cassette, chain rings, and jockeys need to be replaced as well now. Basically they wore down too much and a new chain will not sit correctly on the teeth. Also that looks like it might be a KMC Z6 and Claris is 8 speed so there could be an issue there.
Double check your chain is routed correctly through the derailluer. There is a tab people often route it wrongly against.
Check its not worns against the cassette. The skipping might seem like its happening there but could be elsewhere.
From the information you presented it seems like you should swap in a new jockey wheel.
If that jockey wheel has side to side play then it’s quite possible it’s been pushed inwards leaving space for the chain to climb to the outside. The old chain no doubt had a bit more slop in it whereas the new one is crisper and tighter and less forgiving.
You may be able to put a thin shim behind the jockey wheel to bring it outwards a little, in line with where the chain wants to go.
VERY SIMPLE
Jockey wheel worn too low, needs replacing, didn’t happen on older chain due to chain stretch / wear.
New chain is also too long and needs links taken out for correct tension.
Easy and cheap to replace jockey wheels – £5 + allen key.
Use chain breaker to remove links – £6 tool.
Looks bent but would need to see more pics. Weird it would’ve changed between chains.
It appears to me from the angle of the video that the lower part of the derailleur cage is twisted to the outside? Is the lower pulley parallel/ in line with the chain from the bottom of the front chainring?
Maybe chain links are a bit longer compared to the old one. can you put them side by side?
It’s either wrong chain og worn pulley
I had this issue and it was a stiff link in my chain. Check that all the links bend as they should and wiggle the ones that don’t until they do.
Unfortunately, when you get a new chain, many times you also need a new cassette and sometimes a new derailleur. You may have scored that trifecta. It happens.
In mechanics training we learned that you replace a stretched chain together with the sprocket, because a new chain can skip on a worn‑in sprocket. That’s how you avoid exactly this kind of problem.
Did you also replace the pulleys? I’m pretty sure the 105 lower jockey wheels have an arrow that shows which direction it should turn. That would mean it’s either flipped or the the top pulley wheel in the position of the lower pulley wheel (they’re swapped).
Is the quick link new? Is it the correct quick link for your chain type? 8speed?
Is the wheel in line with the chain or diagonal?
Also maybe some light oil will get the thick factory grease moving.
Correct chain? I was cleaning out my pulley wheels this past weekend and did a little more research on upgrading them for smoother shifting. I have a 9 speed Shimano Sora groupset and was looking at upgrading my jockey wheels and I read that if I put in like Ultegra pulleys, it’ll work, but it may cause problems because they’re meant for an 11-12 speed and the chain thickness may become a factor with skipping like this.
1. while changing the chain is it possible you accidentally bent your rear derailleur hanger slightly?
2. is it possible you moved to a narrower chain like a 8 speed to a 10 speed chain or something where previously the wider chain was more forgiving with the jockey wheel misalignment
Alright so there’s a few possible solutions here:
1. Hanger is bent, the derailleur is out of line and on the extreme end it’s running off the jockey wheel. Solution is to take it to a shop and get them to DAG it. It is worth getting a DAG – I use mine all the time.
2. Chainring is bent. You have a bend in the chainring which is running the chain off the jockey wheel. Pretty straightforward to knock it back in line with a rubber mallet.
3. Wrong chain. This looks like a 10s or 11s derailleur, looks like a KMC 9s chain. It’ll run and shift, but will misalign on components due to the different width. I’ve miscounted gears before, also seen companies ship wrong chains in boxes. It’s an easy mistake to make.
Fundamentally, the lower jockey wheel only provides tension and could be worn all the way to the bearing and you probably wouldn’t notice a difference. This is an alignment issue between drivetrain components, I bet it’s a hanger bend, it’s easy to do and I would guess 75% of hangers out in the world are bent in some way. Hard to gauge chain length from this video, I don’t think that’s the issue here.
are you sure you ordered the correct size as in the distance between the links? How’s it doing on the gear sprocket and the cranking sprocket?
Is the mech or more likely hanger bent at all? How free running are the jockey wheels? They don’t look worn particularly, but if they are stiff to spin at all this will happen.
The wheel looks worn to me. A worn wheel and a brand new chain won’t match up perfectly, not like the worn wheel did with the chain that wore it down
I assume the new chain is made for the rear cassette type (ie 9 sp chain for a 9 sprocket rear cassette). Many times when a chain is replaced because its worn, the rear cassette needs to be replaced also. They wear together. A new chain on a worn rear cassette may have issues like above. I haven’t seen the pulleys wear out though.
Gonna guess bent derailleur
I’d try another 8 speed chain just to rule out this one being weird. It seems like the link spacing is somehow off. If that doesn’t do it, I would replace the jockey wheel
Put old and new chain side by side to see if they align? Also are you sure the chain is not a fake? I’ve seen pictures of chains ordered online that are counterfeit look alikes. Possibly new chain mis labeled Also if possible try another new chain good luck