I can't figure out why I am getting chain skip, what next?
#1
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I can't figure out why I am getting chain skip, what next?
I'm getting really severe chain skip whenever I ride my bike; more often than not when I move off in the big ring, standing & putting torque on the drivetrain, my cranks slip, almost resulting in an accident. I need to fix this, but I can't figure out why it is happening.
I first noticed this last summer and assumed straight away that it was the chain as I'd never replaced it after lots of miles, possibly as much as 12-15,000. I got a new chain, along with some tools and a checker, so I could keep on top of it in future, fitted the chain and tested the bike. It seemed ok at first, but the skipping soon returned. 140 miles after changing the chain, I went out and got hold of a new 105 cassette and installed it, but again, it wasn't a solution, and I haven't rode since.
I've also tried;
Photo of my chainring (click for hi-res). Do they look like they are badly worn? https://imgur.com/a/JeDcWVr
Stock image of a 50 tooth FC-9000 for reference: bit.ly/2VgsVmd
I'm a bit stuck, maybe someone will have a better idea here
I first noticed this last summer and assumed straight away that it was the chain as I'd never replaced it after lots of miles, possibly as much as 12-15,000. I got a new chain, along with some tools and a checker, so I could keep on top of it in future, fitted the chain and tested the bike. It seemed ok at first, but the skipping soon returned. 140 miles after changing the chain, I went out and got hold of a new 105 cassette and installed it, but again, it wasn't a solution, and I haven't rode since.
I've also tried;
- Stripping the chain of its factory grease, wiping down the drivetrain with a solvent, and relubricating the chain.
- Tried a clubmates rear wheel & (different ratio) cassette on my bike, and encountered the same issue. I thought maybe the pawls are not returning (sticky), I want to say this rules this out but maybe I could revisit this one?
- Inspected the chain length, which seems o.k., in big-big combo, I cannot quite turn 2 links over on each other, forming a Z.
- Indexed the gears earlier today; they seem ok, going from 25 to 28 took a fair bit of adjustment but every shift seems smooth, that said, something about the 25 to 28 change still feels the tiniest bit off even though it works, but this isn't usually a jump I would make in the big ring.
- asked a LBS to get into the freehub and check it out, but they couldn't. It's an OEM hub designed not to be disassembled, meaning replacing is the only option.
Photo of my chainring (click for hi-res). Do they look like they are badly worn? https://imgur.com/a/JeDcWVr
Stock image of a 50 tooth FC-9000 for reference: bit.ly/2VgsVmd
I'm a bit stuck, maybe someone will have a better idea here
Last edited by dja1; 04-10-20 at 03:07 PM.
#2
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What kind of frame is this? Steel, carbon? What comes to mind, from someone who rides steel, is the derailleur hanger alignment.
#3
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It's a carbon frame. The hanger looks straight, but I know it's one of those things that sometimes isn't visible to the naked eye, and I understand this may be a poss. culprit.
£25 for a new one from Planet X.
I did crash this thing a while back, but if this was a cause then it's took a while to come to light. I skidded on some gravel, and hit the deck; not too hard mind, but the derailleur 100% did take a whack, as I lost the b-axle cover cap. This happened around 400-500 miles before I noticed the skipping.
Last edited by dja1; 04-10-20 at 03:34 PM.
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Chainring worn completely out? I'm no expert but looking at the profile of the stock chainring photo and your chainring it looks completely different. Looks like lots of wear, even on the flanks of the teeth.
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You know, I didn't look at the pics initially, but I agree with this -- your chainring looks a bit shark-toothy. Maybe time for a new one? Does it skip in the small ring?
#7
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Last edited by dja1; 04-10-20 at 04:27 PM.
#9
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I've ordered a new direct replacement for the chainring. It looks so much different than when it was new as a result of not staying on top of chain changes. Fortunately only 140 miles on this chain and 15 on the casette so they should be fine.
Hopefully I can change the large ring without having to take the cranks off.
#10
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Edit: my new drive train is awesome!!!
Last edited by DeadGrandpa; 04-11-20 at 07:19 PM.
#11
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and a better image of the stock ring: https://bit.ly/34sx4HM
when I compare the teeth above the 'dura-ace' engraving, it seems that those on mine have become more rounded and some have taken a more ramped profile than on the pristine part. I do hope the new ring changes it.
is it worth installing new jockey wheels and gear cables?
turns out it may have less miles than I thought - possibly 6k. Going to need to stay on top of these chains in future and look at my cleaning regime as I always seem to get a gritty/sandy paste in the chain. Are the chain cleaner tools any good?
Last edited by dja1; 04-11-20 at 06:43 PM.
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I first noticed this last summer and assumed straight away that it was the chain as I'd never replaced it after lots of miles, possibly as much as 12-15,000. I got a new chain, along with some tools and a checker, so I could keep on top of it in future, fitted the chain and tested the bike. It seemed ok at first, but the skipping soon returned. 140 miles after changing the chain, I went out and got hold of a new 105 cassette and installed it, but again, it wasn't a solution, and I haven't rode since.
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#13
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more detailed pics: https://imgur.com/a/rCUDhVb
and a better image of the stock ring: https://bit.ly/34sx4HM
when I compare the teeth above the 'dura-ace' engraving, it seems that those on mine have become more rounded and some have taken a more ramped profile than on the pristine part. I do hope the new ring changes it.
is it worth installing new jockey wheels and gear cables?
turns out it may have less miles than I thought - possibly 6k. Going to need to stay on top of these chains in future and look at my cleaning regime as I always seem to get a gritty/sandy paste in the chain. Are the chain cleaner tools any good?
and a better image of the stock ring: https://bit.ly/34sx4HM
when I compare the teeth above the 'dura-ace' engraving, it seems that those on mine have become more rounded and some have taken a more ramped profile than on the pristine part. I do hope the new ring changes it.
is it worth installing new jockey wheels and gear cables?
turns out it may have less miles than I thought - possibly 6k. Going to need to stay on top of these chains in future and look at my cleaning regime as I always seem to get a gritty/sandy paste in the chain. Are the chain cleaner tools any good?
As for cleaning the chain, I use a cheap pressure sprayer to knock off the crud and grit, spraying into the grooves of the cassette and derailleur while rotating the chain and chainrings. Then use WD-40 to get the water out of the chain links, then the chain lubricant of your choice. I use Fluid Film, a lanolin based industrial product, but anything including 3 in 1 oil is better than nothing. Hundreds of threads about that. Flush the grit out, replace with oil of some kind. Replace when it wears out, apparently.
#14
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When people describe this behavior, I usually assume it is a free hub issue: a sticking pawl, or a damaged one (broken, spring damaged, etc). Though it is possible I don’t understand what you mean by “skipping”. If you put pressure on the pedals and the crank slips forward, chain/chainrings aren’t the first place I’d look.
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The teeth on the big ring are pretty worn from that old chain. Replace the ring and things should work better, I doubt your rear hub has anything to do with the skipping.
#16
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There are those who contend that chainrings will never skip. Worn chain rings will cause chain suck, where the chain comes around the back side and won't release.
Normally, chain skip occurs when a new chain is installed on a worn cassette. Even then, the skipping will only occur on a few of the most worn sprockets. It should only be noticeable when pedaling with a high torque, like might occur when pedaling up a hill, with a low cadence and pushing hard on the pedals. Then the chain skips over the top of some of the teeth and only transmits power intermittently. Chain tension is greatest when using the little ring and more likely to cause chain skip.
While it is possible for chain skip to occur with a very worn chain and cassette, the chain must have some very extreme elongation. If a new chain is installed on that cassette, it will most certainly skip.
A faulty freehub might skip at any time, in any gear combination and may result in the crank dropping quickly to the bottom of the stroke, with no forward motion of the bike.
When the problem occurs, you need to pay attention to what's going on.
Normally, chain skip occurs when a new chain is installed on a worn cassette. Even then, the skipping will only occur on a few of the most worn sprockets. It should only be noticeable when pedaling with a high torque, like might occur when pedaling up a hill, with a low cadence and pushing hard on the pedals. Then the chain skips over the top of some of the teeth and only transmits power intermittently. Chain tension is greatest when using the little ring and more likely to cause chain skip.
While it is possible for chain skip to occur with a very worn chain and cassette, the chain must have some very extreme elongation. If a new chain is installed on that cassette, it will most certainly skip.
A faulty freehub might skip at any time, in any gear combination and may result in the crank dropping quickly to the bottom of the stroke, with no forward motion of the bike.
When the problem occurs, you need to pay attention to what's going on.
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Ya chainring is munted... (That's Aussie for your chainring is worn beyond it's serviceable limits)
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