Replacing cassette or changing sprockets?

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  • What is the general consensus on changing sprockets in a rear cassette?

    I have a 11-29t Campagnolo Potenza 11sp cassette. With a new chain, the 17 & 19 sprockets skips due to wear. This one and the 21 are the ones that I use most.

    Two options now: replacing the entire cassette (+- 125 euro) or replacing the worn sprockets. Campagnolo offers a 17-19-21 replacement (code 11S-791 - price +/- 45 euros).

    Is there any disadvantage or no - go for replacement sprockets? What is the general opinion on this?

  • Are you set on a Potenza cassette?

  • Not really, I think? Do you have other recommendations?

  • Thought I’d replied.

    You could get a centaur 11sp cassette for much cheaper, and there’s little difference in terms of performance.

    Alternatively you could get a Miche cassette for near the price of the sprockets you’ve identified. The cassette is entirely loose cogs so replacing one cog would be easier in the future. It’s so much cheaper you could afford a cassette and 2-3 SRAM chains instead of a Potenza cassette. Just make sure you get the right cassette for your freehub!

    11 speed drivetrains don’t have as large a tolerance for misadjustments as, say, a 9 or even 10 speed would, so the general consensus is to change chains at 0.5% wear, and change cassettes every 2-3 chains. Changing single cogs one at a time until the casete works perfectly might prove tricky and more expensive than getting a new part.

  • thanks @Hjusth for the info. In the end I've bitten the bullet and went for a full Chorus 11sp cassette (110 euro) + and new TA chainring. Didn't want to mess up the new chain (potenza) and cassette with a worn chainring.

    Curious about the durability of the potenza chain. I've used a KMC 11 speed and was suprised about fast (<5000km) is was completely worn out (1.0) . This messed up the sprockets and the cassette and also the chainring. I'm quite strict in cleaning + greasing though. Will check wear more regularly for sure.

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  • Nice one 👍 I haven’t used KMC 11sp but I’ve always had good mileage from Campag chains. What conditions were you using it in? SRAM makes competitively priced 11sp chains that work perfectly with Campag as well.

    You might be able to get a few EUR on eBay or on here for your cassette if you want to sell.

  • Flemish conditions (good weather - bad weather - dirty roads - short climbs) but chain was maintained well. Cleaned with a rag after every ride, dry lube when needed. Cleaned in ultrasonic cleaner for 2 or 3 times.

    I'm going to put the cassette on my turbo trainer bike. Still works fine with a 0.5 chain.

    How would you judge the chainring on the picture? Replacement is ordered, but what is the 'amount' of wear here?

  • Looks like you’ve got a few sharks teeth. How far does the chain pull off the ring if you pull it at 3 o’clock?

  • I have a similar problem to you on a Chorus 11 speed cassette. Skipping on 17-19-21.

    Would you mind posting a photo of these 3 cogs to show the level of wear.

    In my case the wear does not stand out at all but skipping is really bad.

  • I've already swapped the chainring, so can't check anymore unfortunately . Compared with new TA ring:

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  • Will make a picture!

  • Cheers. Here's a couple of pics of mine. Was surprised to get skipping on these as I thought not much wear.

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  • I’d say it was the right call. The teeth at 7 to 8 o clock in that pic have what looks like signs of wear (they’re starting to look like sharks teeth).

    Good heads up about your KMC 11 chain wearing quickly, will be mindful if I ever use one.

  • Here are some detailed pictures of the cassette. Cog 17t and 19t skipped with the new chain. What worries me is the chain wear on the cogs, which I marked in red. Is this supposed to be normal wear? No play at all on body, lockring was always torqued right...

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  • Was your derailleur properly indexed?

  • You can see similar round markings on mine but maybe not as pronounced. I bought this cassette second hand as shown so no idea if the previous owner had his RD adjusted properly or not.

    I compared mine to an image of a new set of 17-19-21 from an onine store. The teeth do look to be narrrowed down on both forward and backward facing edges but I don't see any sign of the hook or shark tooth shape you see in worn cassettes. I'd estimate the width of the teeth are reduced by about 30-40%.

    Replacement cogs cost nearly the same as a full Miche cassette so I've got a Miche on order.

  • Yes, shifting has been good. In the workstand, not the most silent but on the road it was all quiet and shifting was good. The marks would indicate to much cable tension I assume, whereas shifting to harder gears was always crisp.

    Which reminds me that I've been riding for An unknown time (I expect it to be +-500k) with a derailleur hanger that had play. Maybe this caused it, as subsequently the derailleur had some free play to move once it was indexed in a gear?

  • Always difficult to asses cassette wear, at least for me!

  • I've been getting skipping on my Shimano HG800 11 speed cassette on the smallest 3 or 4 sprockets of my 700c rear wheel after fitting new chain. Have same cassette on 650b wheel with no issues. Can't visibly tell the difference between 2 cassettes in terms of wear on sprockets (i.e. no sharks teeth) except on a few of the teeth on the 700c one there appears to be small lips on the edges. Wouldn't have thought enough to cause skipping? Also, never had that kind of wear on sprockets before...

  • Definitely chain skipping over the sprocket and not indexing of gears or freehub skipping that could be to blame?

  • I'll check but previously the two cassettes both worked perfectly with the same indexing. That said, I did replace the gear cable recently and reindex so it may be a little out this time and only apparent on one.

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Replacing cassette or changing sprockets?

Posted by Avatar for Flandria @Flandria