Can anyone tell how worn this cassette is?

broady

Über Member
Location
Leicester
20201220_104330.jpg

Was told that the cassette has covered about 400 miles, but want to know if any of you experts can tell me if it is worn. The reason is the chain it came with was worn.
Thanks
 

OldShep

Senior Member
Assemble with new chain and see if it slips. That’ll answer your question.
I can never, unless totally, tell by looking.
 

gbb

Legendary Member
Location
Peterborough
.photo isn't really detailed or clear enough but as said, the only sure way is to put a new chain on and see if it slips.
(I've seen cassettes that were quite clearly and obviously worn but thaats usually very obvious)
Edited to add, the photo is clear, I needed my glasses :tongue:...but stick a chain on and try, it's the only sure way.
 
OP
broady

broady

Über Member
Location
Leicester
I have put a new chain on and took it for a gentle ride up a hill and it wasn't slipping, so hopefully all good.
The chain was well worn, well past both markers.
Cheers
 

Paulus

Started young, and still going.
Location
Barnet,
I have put a new chain on and took it for a gentle ride up a hill and it wasn't slipping, so hopefully all good.
The chain was well worn, well past both markers.
Cheers
The largest three cogs are a little worn, some of the teeth are shark finned, but if the chain doesn't slip, then alls well.
 

Ajax Bay

Guru
Location
East Devon
Was told that the cassette has covered about 400 miles, but want to know if any of you experts can tell me if it is worn. The reason is the chain it came with was worn.

I have put a new chain on and took it for a gentle ride up a hill and it wasn't slipping, so hopefully all good.
The chain was well worn, well past both markers.
You can't tell how worn a cassette is by visual inspection, as @OldShep says.
But I think you need to take it for a less than gentle test. Only a gentle hill is required but you need to give it some welly (standing up with expectation of a jolt) in several of the middle-of-the-cassette sprockets. You will get the test results quite quickly.
If you DON'T get slip/skate then the chain (worn to >0.75%) that came with it (ie from the seller/donator) must have been used on another cassette and then the previous user had changed to this cassette but not the chain (poor practice). It's possible that the cassette has not been worn too much by the elongated chain in 400 miles. In which case you're lucky. Ride on with the new chain.
If you DO get slip/skate then refit the old chain and run the chain/cassette combo till you do get slip/skate. Then replace both at the same time.
 

piglet

Member
As stated by Shep visual examination will not give wear on a cassette neither will the recorded mileage of 400 miles be accurate.400 miles in wet gritty mud etc. will wear more than dry well maintained and oiled chain.Also there are 10sprockets to wear from 1chain.Most use will generally be made on the mid range of the cassette.Wear rate is generally greater on the smaller than larger sprockets given the same usage,so wear related to miles or time is virtually impossible.A worn chain will definitely accelerate wear.As the chain has a pitch of1/2 inch when new it sits in the bottom (root) of the sprocket .When wear occurs it stretches and goes out of pitch causing it to ride up the tooth of the sprocket when under load.A new chain restores the correct pitch and ride in the root of the sprocket.A quite worn sprocket will work OK with a new chain.Also if the individual sprockets are symmetrical and can be placed either way on the body (some Shimano cannot),reverse the sprocket when fitting a new chain and you have new wearing surface.Double the life and half the cost.Chain wear is the key.Also related is chain ring wear .Most wear on the chain ring occurs when the crank moves from top dead centre to approx.3 o'clock.(both sides).This can be observed on a well worn ring .Moving the ring in relation to the crank will even out the wear.P.S. I am from Yorkshire so we want full value for money.Hope this helps.
.
 

Ajax Bay

Guru
Location
East Devon
A quite worn sprocket will work OK with a new chain.
:welcome: Can you expand on that? Don't you find that a new chain on a 'quite worn' sprocket will skate?
I think you'd be interested in this thread: https://www.cyclechat.net/threads/why-a-worn-cassette-cannot-damage-a-new-chain.255700/
And on chainrings (rotation of), this one: https://www.cyclechat.net/threads/knackered-chainrings.258315/
In a situation like this, would rotating the chainring in the spider so that the worn area sits where your green circle is make sense, or is the chainring too far gone.
In theory, yes.
There is a caveat or two though. Some chainrings are now matched to crank in a 3D way, so offset is not possible and/or not aesthetic.
Secondly, there's a pin embedded in the chainring that prevents the chain from falling between the crank and the spider. Should that pin now go where it can't do it's job, a chain that came off is a ride-stopping event. A chain jams extremely tightly into that V space. You will have to carry your bike home.
Thirdly, the shifting will be slightly iffy because the ring has specially-positioned ramps and pins that make the chain shift in special places, such as when you can't power the drivetrain because the pedals are in the 12 and 6 o clock positions etc. However, this can be overcome and is no big deal.
Chainrings will missing teeth still work perfectly provided you don't shift on the missing tooth. There is plenty of "wrap" to not even notice it.
 
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Ajax Bay

Guru
Location
East Devon
I agree the cassette in the OP's image looks 'like new'. @OldShep has offered an assessment assurance mechanism (Post #2) (and I've offered an aligned protocol (ETA after @Ming's below: Post #7 " a gentle hill is required . . give it some welly . . in several of the middle-of-the-cassette sprockets").
Here's a test: Please could the OP run the cassette with the same chain for 4000km, give it a good clean and then re-present an image of it for any and all CycleChat accredited 5* diagnosticians to give their judgement(s).
A definition of "worn" will of course be required. @matticus or @weareHKR care to offer one?
For me 'worn' means that a new chain will skate when power applied on the most-used sprocket (?16t say).
 
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Ming the Merciless

There is no mercy
Location
Inside my skull
It tends to be specific cogs that slip , not all of them, as some are used more than others and wear rates are different even if equally used from a time perspective. Do your test uphill across every cog on the cassette and make sure you’re putting some effort in, not gently spinning.
 
It tends to be specific cogs that slip , not all of them, as some are used more than others and wear rates are different even if equally used from a time perspective. Do your test uphill across every cog on the cassette and make sure you’re putting some effort in, not gently spinning.
And after doing this you still won’t be sure how worn your cassette is, but you’ll be a damn sight fitter. :laugh:
 

matticus

Über Member
Here's a test: Please could the OP run the cassette with the same chain for 4000km, give it a good clean and then re-present an image of it for any and all CycleChat accredited 5* diagnosticians to give their judgement(s).
A definition of "worn" will of course be required. @matticus or @weareHKR care to offer one?
No problem:

not like the one shown in Post #1.

(Don't forget to rate this post folks!)
 
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