# How long would it take to ruin a new chain with an old cassette?



## melanerpes (Apr 4, 2007)

I installed a new chain (ultegra) this winter and only road it on the trainer...no problems. During my first ride on the road this spring (on that bike) the chain was slipping and driving me nuts. Clearly my cassette is in worse shape than I thought. I already ordered a new cassette but I'm wondering if I ruined the chain from 30ish hours on a trainer and 2 hours on the road?


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## bytewalls (Feb 14, 2010)

You usually get about 2000 miles per chain. By my guess you have probably 750 to 1000 miles on it. that said uauing a worn out cassette with it could wear the chain out faster. I would start by giving it a good adjustment, if that doesn't fix it replace the cassette and measure the chain. remember that the longer you in run worn out parts the quicker everything else wears out (you aren't saving money)


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## aclinjury (Sep 12, 2011)

are you sure it's the cassette and not the derailleur that's causing the jump??


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## MMinSC (Nov 19, 2011)

It'll be okay. The chain may have worn in a bit, and may click and pop for the first few miles on the new cassette, but it'll knock the burrs off the new cassette and be okay!


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## melanerpes (Apr 4, 2007)

aclinjury said:


> are you sure it's the cassette and not the derailleur that's causing the jump??


Yup, pretty sure. It shifts just fine, it only pops when climbing or sprinting.


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## JCavilia (Sep 12, 2005)

melanerpes said:


> Yup, pretty sure. It shifts just fine, it only pops when climbing or sprinting.


And only on certain cogs, I assume? If so, then you're right about the worn cogs.

Have you measured the chain to see if it's elongated? I agree with the others who've suggested you prabably haven't done much to the chain. But it's easy enough to check. You do want to keep an eye on this chain, if there's any premature wear, so you don't wreck a new cassette sooner than necessary.


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## C-40 (Feb 4, 2004)

*info...*

The old cassette has no effect at all on the chain, it's just a nuisance that it skips on the most-worn cogs. If you were able to tolerate the skipping for a few hundred miles, it would actually quit.


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## Pieter (Oct 17, 2005)

C-40 said:


> The old cassette has no effect at all on the chain, it's just a nuisance that it skips on the most-worn cogs. If you were able to tolerate the skipping for a few hundred miles, it would actually quit.


I remain pretty convinced that worn cogs give a new chain's rollers a hard time. A worn chainring, likewise.


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## Blue CheeseHead (Jul 14, 2008)

C-40 said:


> The old cassette has no effect at all on the chain, it's just a nuisance that it skips on the most-worn cogs.


Agreed. The rollers on the chain will prevent damage due to the worn cassettee. A chain's enemies are dirt and lack of lubrication.


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## Blue CheeseHead (Jul 14, 2008)

Pieter said:


> I remain pretty convinced that worn cogs give a new chain's rollers a hard time. A worn chainring, likewise.


Yes, the rollers may roll a bit more than under ideal circumstances but if the chain is clean and lubricated, the impact should be minor.

A dirty, worn out chain will impact wear on the chainrings and cogs to a larger extent because in that scenario the chain rollers would not be working as well.


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## DevinB12 (Nov 8, 2011)

Ok, let me ask this, I'm changing a cassette, should I change the chain at the same time? I'm running Ultegra chain right now, it has 3300 miles on it but the chain tool I purchased to check it doesn't show that it has stretched to the point of replacing it....but should I replace it anyway? And should I spend the money on the Dura Ace chain or is there not enough benefit to that and stick with a new Ultegra chain?


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## Kerry Irons (Feb 25, 2002)

*Chain tools*



DevinB12 said:


> Ok, let me ask this, I'm changing a cassette, should I change the chain at the same time? I'm running Ultegra chain right now, it has 3300 miles on it but the chain tool I purchased to check it doesn't show that it has stretched to the point of replacing it....but should I replace it anyway? And should I spend the money on the Dura Ace chain or is there not enough benefit to that and stick with a new Ultegra chain?


You will need to change the chain if it is worn out. Worn out = 1/16" elongation in 24 links (12 inches original length). Toss your chain checker and use just about any ruler. Alternatively you can buy a chain and put on the new cassette (old chain). If the new cassette and the old chain play nice together, then keep the new chain for when the old chain wears out.

Value is a question no one can answer for you. The primary "advantage" of the DA chain is 15 grams saved. Whether that is worth $8 is hard to say.


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## Nicole Hamilton (Sep 5, 2010)

Cogs aren't as sensitive to chain stretch as chainrings because there are so few links in contact with a cog. On the big chainring, you might have 27 links in contact. But on a cog, maybe only 9 or fewer. It's the _accumulated_ stretch over a lot of links that prevents some of them from fitting properly over the teeth.


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## bytewalls (Feb 14, 2010)

Nicole Hamilton said:


> Cogs aren't as sensitive to chain stretch as chainrings because there are so few links in contact with a cog. On the big chainring, you might have 27 links in contact. But on a cog, maybe only 9 or fewer. It's the _accumulated_ stretch over a lot of links that prevents some of them from fitting properly over the teeth.


 Cassettes are designed so that one tooth holds the load of the chain at a time. This means that there is a lot of force on that one tooth and that it wears faster than a chainring, plus supporting additional force means that small imperfections matter more. https://www.bikerumor.com/wp-content/uploads/2012/02/2012-SRAM-Red-Powerdome-x-cassette-diagram.jpg


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## Nicole Hamilton (Sep 5, 2010)

bytewalls said:


> Cassettes are designed so that one tooth holds the load of the chain at a time. This means that there is a lot of force on that one tooth and that it wears faster than a chainring, plus supporting additional force means that small imperfections matter more. https://www.bikerumor.com/wp-content/uploads/2012/02/2012-SRAM-Red-Powerdome-x-cassette-diagram.jpg


That's the same force and the same wear as always, whether the chain is brand new or been used for thousands of miles. But there just isn't enough _*stretch *_over only a few links for the stretch to be the big factor. It's the mismatch over a _*lot *_of links that means not all the chain can settle down on the teeth on a chainring. It'd be hard to stretch a chain enough to get that effect on a cog.

You need to look at a bike with a stretched chain to see this. It'll wrap the cogs just fine and may even wrap the small chainring okay. But it won't wrap the big chainring properly and beginning around the 3 or 4 o'clock position on the big chainring, the accumulated stretch will be enough the chain won't fit properly and links will ride high on the teeth.


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## ncroadrider (Aug 23, 2004)

*Chain, cassette, crankset compatibility*

I am running an ultegra cassette, chain and crankset. I recently purchased a new sram cassette and chain. Shifting is alright in the big ring but skips in the inner ring up front. Is my inner ring worn or is there a compatibility issue. I also replaced my rear derailleur cable and housing.


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