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#1
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New chain skips on _new_ cassette
I replaced my cassette and chain at the same time. The chain was an
old style with bushings and it skipped on the smaller sprockets, which I attributed to it being pushed sideways by the ramps because it was too wide. However, after about three miles I realized that it was also skipping on the front chainring, which turned out to be very worn. Now with new chainrings and a narrower chain ("SRAM-PC58"), I get skipping on the 13t sprocket. (Both the 15t and 11t seem OK but I have ridden much yet.) Of the three miles ridden with the wider chain and worn chainrings, less than 1/2 mile was probably on the 13t sprocket. Most was probably on the 18t sprocket. The narrower chain was ridden about 100 feet on the worn chainrings. I do see wear from this, I think: 24 links measure about 24 1/32 inches. I don't have the other chain in front of me to measure it. Is it possible that the chainrings wore the chain which in turn wore the cassette sprocket to the point where a new chain now skips on it, all in 1/2 mile? Any other explanations? Anything I can do about it? Also, does my thought for why the chain with bushings was skipping seem right? It's called a 6/7-speed chain ("KMC-HP20"), on a 7-speed HG cassette--it seems like it should have worked. Thanks, Karl Nelson. |
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#2
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New chain skips on _new_ cassette
I've had new chains skip on new freewheels (none of this high tech
stuff) and it stopped when the chain wore a little. That was years ago though. I'd be surprised if anything skipped on the chainring. The chain tends to pop off when it skips there. It's winding on under tension on the chainrings and so doesn't ride up on a tooth the way it does on a worn cog. So skipping on the chainring is most likely an optical illusion. Stiff link is the usual explanation. The stiffness only have to be stiff against the derailleur tension, not your pedalling tension. A skip is caused by a hook in a worn cog, which lets the chain pull up inside the hook, so the oncoming link doesn't clear the tip of the next tooth (unless the chain isn't stretched); the chain then rides on top of the teeth until the whole army gets to the top of the cog, and then everything slips until a random link catches a bottom tooth. A burr on a cog could conceivably cause the same sort of thing, I guess. -- Ron Hardin On the internet, nobody knows you're a jerk. |
#3
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New chain skips on _new_ cassette
I've had new chains skip on new freewheels (none of this high tech
stuff) and it stopped when the chain wore a little. That was years ago though. I'd be surprised if anything skipped on the chainring. The chain tends to pop off when it skips there. It's winding on under tension on the chainrings and so doesn't ride up on a tooth the way it does on a worn cog. So skipping on the chainring is most likely an optical illusion. Stiff link is the usual explanation. The stiffness only have to be stiff against the derailleur tension, not your pedalling tension. A skip is caused by a hook in a worn cog, which lets the chain pull up inside the hook, so the oncoming link doesn't clear the tip of the next tooth (unless the chain isn't stretched); the chain then rides on top of the teeth until the whole army gets to the top of the cog, and then everything slips until a random link catches a bottom tooth. A burr on a cog could conceivably cause the same sort of thing, I guess. -- Ron Hardin On the internet, nobody knows you're a jerk. |
#4
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New chain skips on _new_ cassette
Ron Hardin wrote:
next tooth (unless the chain isn't stretched); the chain then rides unless the chain is stretched edit error -- Ron Hardin On the internet, nobody knows you're a jerk. |
#5
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New chain skips on _new_ cassette
Ron Hardin wrote:
next tooth (unless the chain isn't stretched); the chain then rides unless the chain is stretched edit error -- Ron Hardin On the internet, nobody knows you're a jerk. |
#6
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New chain skips on _new_ cassette
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#7
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New chain skips on _new_ cassette
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#8
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New chain skips on _new_ cassette
also, if using a superlink of some sort, they may need special orientation
when installed. I got a connex (I think) which is asymmetrical, and only goes 1 way. I didnt understand from the directions initially, and installed it correctly by accident. the next time I cleaned the chain and re-installed the link, it began to skip, but only in the 11T. A Park gauge showed less than .25 wear, and I knew the chain had less than 1000 miles. turned out the link was on backwards. |
#9
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New chain skips on _new_ cassette
also, if using a superlink of some sort, they may need special orientation
when installed. I got a connex (I think) which is asymmetrical, and only goes 1 way. I didnt understand from the directions initially, and installed it correctly by accident. the next time I cleaned the chain and re-installed the link, it began to skip, but only in the 11T. A Park gauge showed less than .25 wear, and I knew the chain had less than 1000 miles. turned out the link was on backwards. |
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