This cassette's basically ok, right?

[swee'pea99]

Changed the chain, and my daughter reports a bit of chattering/roughness. I've heard this can happen if the cassette is excessively worn, but it doesn't look bad to me. No really bad sharks teeth. I mean, it's covered a fair few miles, but it's still basically in ok nick, right? Or do you think otherwise...?

 

[Ming the Merciless]

Gears adjusted correctly and she’s not cross chaining?

 

[iluvmybike]

Assuming gears are all nicely adjusted and rd is straight then If it has done a fair old mileage then it will need changing. They are not expensive. It's hard to see 'wear' in a cassette (unless it is mega bad). If you keep it do it a favour and remove it and give it a good clean

 

[si_c]

You won't be able to see if a cassette is worn visually. If it rolls fine and shifts fine then nothing to worry about, you'll know if it needs changing if the chain skates over the top whilst pedalling.

It's most likely a lighter lubricant on the chain from the factory which is causing slightly more noise than before. If unsure clean and relubricate the chain.

 

[Cycleops]

As above, you really can't tell sometimes. If you've changed the chain the cassette will need a replacement. Slipping is the usual symptom. If the roughness persists look for other causes.

 

[Ajax Bay]

Changed the chain, and my daughter reports a bit of chattering/roughness. [Is] the cassette is excessively worn, . . . ?

Test it yourself to confirm or otherwise your daughter's report.
I don't agree with @Cycleops binary advice that the cassette needs replacing.
Take the bike out for a quick 'full power' test on a slight hill, in all the middle sprockets. If that's OK then ride on. If it slips, then you need to replace the cassette.
I'd leave the storage/sale lubricant on the chain for the first 500km. It will not be the chain lubricant causing this.

 

[Dave Davenport]

If you've changed the chain the cassette will need a replacement.

I reckon I change the cassette about every third chain, as long as you do it before it gets too worn seems to be about right. Even when I've fitted a new chain with a cassette that probably should have been changed as well and it's a bit notchy it's bedded in and been ok after a couple of hundred miles, obviously if it's too far gone and slipping you're going to have no choice but to change it.
Yes, I am a bit of a skinflint when it comes to bike maintenance.

 

[gbb]

The one thing I've noticed a couple times immediately after putting a new chain on a used cassette is a mechanical vibration with a slight associated noise like a whirring. It's reasonable to assume it the slight mismatch between new chain and old cassette. That might not be what's actually happened but my interpretation of it. It passes after a couple rides, presumably as the chain meshes. Could that be what is being reported ?

Alternatively, the transmission is a relatively simple thing, if there were no noise, no cause to assume there might be maladjustment before the change, it's reasonable to assume the cassette is worn then...and change it.

In my humble opinion, theres often discussion about when, how to know when things should be changed, chains particually. These are consumable items, they dont last forever, personally I'd just change it. Realistically, if it was fine before, theres only really two things to consider.

 

[fossyant]

It's dirty !!

 

[fossyant]

Looks fine for wear. Modern cassettes have special profiles on the teeth, and they look like what I'd espect for a normal cassette that's not worn.

 

[SkipdiverJohn]

Yes, I am a bit of a skinflint when it comes to bike maintenance.

By my standards, you are somewhat extravagant. I keep all my old chains and use them to replace the ones that I encounter on salvage finds or cheapo secondhand purchases that are actually rusted solid, damaged, or just missing completely. I've never binned a still-functional freewheel either.

 

[cheys03]

Is the roughness in all gears? looks ok except maybe the smallest sprocket

 

[swee'pea99]

Thanks very much for all responses. Clearly it's not horrendous! I'm pretty sure it's not slipping, which seems to be the sign of it being proper bad. I think for the moment I'll take my usual approach: leave it and see how things go, review the situation after a few more rides. Thanks again.

 

[Ajax Bay]

I think it'd be worth extending the 'clean for a photo' area to 360 degrees and the smallest sprocket and lockring and probably a chain clean and re-lube. That might quieten your daughter's bike. However, perhaps like you, I am trying to encourage offspring to 'do it themselves'.

 

[Blue Hills]

If you've changed the chain the cassette will need a replacement.

Not every time surely cyclops unless you have let the chain get really really worn? I have the idea that by changing chains at no more than 0.75 wear (if not above 9 speed) you will maybe get to use a cassette with about 3 chains.
Agree with folks that it can be a bugger to tell if a cassette is actually worn from a look though have no idea why this is.
I'd check all the indexing, clean the factory lube off the new chain and relube, try again, then if that doesn't work, while keeping the old cassette to hand, fit a new cassette and see what things are like then.