Is this a worn cassette/chain, or am I missing something?

[Andy in Germany]

Another bike on the stand, and after I'd straightened the rear mech hanger and replaced the cable, I was still getting a consistent clicking noise and chain vibration. It took longer than I'm prepared to admit before I traced it to this:

View in silhouette makes it more clear:

When this happened on a chain wheel a week ago, the consensus was it was a heavily worn chain. Is that the case here? The cassette does show signs of being worn, but I want to be sure it isn't something else before I talk to my clients about it tomorrow; the bike was, again, in the showroom as "ready for sale"...




The problem becomes gradually less pronounced as I shift into the higher gears but it is still present.

 

[Deleted member 1258]

Knackered cassette, I'd change both chain and cassette.

 

[Paulus]

The cassette looks toast and it should be in the skip
The chain has probably had it as well.
The higher gears may work and sound a bit better, probably 'cos they haven't had as much use.

 

[Slick]

Someone will be along that might pander to your Scottish heritage and tell you that you would get another 5000 miles our that set up by just employing the Mickle method, but the truth is, its goosed mate.

 

[I like Skol]

Chain is massively worn and elongated. Freewheel is wrecked and chainrings are likely not in great shape either. This is the point where a cheap bike becomes uneconomical to repair in many cases.

 

[Andy in Germany]

Many thanks. I'd suspected this but getting it confirmed helps if I have to present this to sceptical clients saying things like "We would have sold that before you came, no problem" which, on the face of it, is a fair comment.

Chain is massively worn and elongated. Freewheel is wrecked and chainrings are likely not in great shape either.

Thanks for the summing up @I like Skol. How can you see this? The worn teeth are far more obvious in the image than when looking at the actual cassette, and I know that means the chain must be seriously overstretched*. Are there other details I'm missing? When you say the "Freewheel is wrecked" are you referring to the cassette?

I'm also assuming that any attempt to replace with a second hand freewheel and chain is unlikely to succeed because they'll have different wear patterns, so I'd need to get a new cassette, at which point we may as well strip the bike down for parts.

*One of the first tools I ordered is a chain measuring tool...

 

[Ajax Bay]

It's a freewheel (7sp block) not a "cassette". Can you see a lockring? That's what Skolly is pointing out, quietly and politely (to all the 'replace the cassette' boyos) upthread.
The chain has elongated so much the block will be beyond use. Put a new chain on and it will skip like a fairy. Both require replacement (not expensive).

 

[fossyant]

Yup, Bar of Fu....ed

 

[I like Skol]

Pretty sure that what you are showing us is a 7speed screw on freewheel rather than a cassette.

The chain elongation is clear in the first picture where at the top of the sprocket the chain is sat in the teeth but at the bottom the chain pins are almost aligned with the points of the teeth. This is approx half a tooth over 11 suggesting a rough chain elongation of approx 4%

At this level of wear probably the best way of measuring it would be to put the worn chain alongside a new one.

 

[wafter]

Pretty sure that what you are showing us is a 7speed screw on freewheel rather than a cassette.

The chain elongation is clear in the first picture where at the top of the sprocket the chain is sat in the teeth but at the bottom the chain pins are almost aligned with the points of the teeth. This is approx half a tooth over 11 suggesting a rough chain elongation of approx 4%

At this level of wear probably the best way of measuring it would be to put the worn chain alongside a new one.

This. To my post-night-in-the-pub eye it seems that chain wear is the predominent issue since its effective pitch varies with wear, and we can see that the links at the top of the image are roughly in the right place on the sprocket while those near the bottom are clearly not.

If sproket wear was the biggest issue the chain would be sat high on all the teeth by the same amount; rather than being centred on some and progressively riding up the teeth as they work around the sprocket.

That's not say that the sprocket's not also worn, however if you have one to hand I'd definitely be chucking on another chain before binning anything.

 

[Milkfloat]

“Ready for sale“ looking that filthy?

 

[Andy in Germany]

Pretty sure that what you are showing us is a 7speed screw on freewheel rather than a cassette.

It's a freewheel (7sp block) not a "cassette".

Sorry, it was late when I posted and I got sloppy in my writing.

 

[Andy in Germany]

“Ready for sale“ looking that filthy?

That's after I gave it something of a clean so I could see what I was doing. As mentioned elsewhere, I'm working on the quality control issues...

 

[Andy in Germany]

Both require replacement (not expensive).

That's not say that the sprocket's not also worn, however if you have one to hand I'd definitely be chucking on another chain before binning anything.

I'm trying to decide if it's worth investing more time in the bike, as we'll not get more than 80€ for it.

Although to be fair it doesn't look like whoever said it was ready for sale invested much time in it, so maybe it'll work out...

 

[CharlesF]

Even if you only get €80, is it good training for the client? Able to see the before and after repairs.