Cassette question

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fastpedaller
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Location: Norfolk

Re: Cassette question

Postby fastpedaller » 9 Oct 2019, 8:38pm

Having in the past run a chain to 1%, and found I then had to replace the cassette as well, I now run to 0.5% and have found this works ok with a new chain. I'd like to know what others think re the longevity of these modern parts though...…… Years ago when I was using regina freewheels, a 10 speed transmission with a renolds (or latterly sedisport) chain I could just run the parts with very little maintenance, and the parts suffered very little wear.
Are the modern chains or sprockets just not durable?

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Cassette question

Postby Brucey » 9 Oct 2019, 9:05pm

BITD I used sedisport chains and they only lasted a couple of thousand miles (tops) before the sprockets would be worn enough that they wouldn't take a new chain without skipping. If conditions were, uh, 'adverse' then it could be a lot less than that.

I got through dozens of the things, not to mention lots of freewheels that got too worn because I didn't always check my chain often enough.

I got so cheesed off with this rigmarole on my training bike, that I built a machine with a hub gear for training on. It was very possibly the cleverest thing I have ever done.

I don't think that (cheapish) KMC chains today are very much different in wear resistance tbh. It would be easy enough to compare them, after all SRAM PC850 is basically the same now as a Sedisport was then.

Note that with 7s (BITD) the sprockets were 2mm thickness, and up to/including UG most sprockets were made of hard, relatively brittle steel that was relatively slow-wearing but would crack if you shifted clumsily under full power too often. With modern sprockets they are are made of softer steel (which may bend rather than break if you shift under full power) and are as little as 1.6mm thickness. You won't be surprised to hear that I think they wear faster, and it is more important than ever that you don't run with a worn chain; if you do the sprockets wear to a bad shape more quickly.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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fausto99
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Joined: 19 Sep 2011, 10:06am

Re: Cassette question

Postby fausto99 » 9 Oct 2019, 10:19pm

When I was commuting, I now realize I used to not worry too much about the chain or cassette until something didn't work :oops: . Now I'm retired, have more time and have read this book https://www.amazon.co.uk/Everything-nee ... oks&sr=1-7 , I change chains at the 0.5% elongation wear point.

I also use an ultrasonic cleaner at every clean before I apply any more lubricant. A bit OTT I suppose but the geartrain and changes are so much smoother and more pleasant to use. I'm a happy bunny :lol: .

fastpedaller
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Location: Norfolk

Re: Cassette question

Postby fastpedaller » 10 Oct 2019, 8:57am

Brucey wrote:
Note that with 7s (BITD) the sprockets were 2mm thickness, and up to/including UG most sprockets were made of hard, relatively brittle steel that was relatively slow-wearing but would crack if you shifted clumsily under full power too often. With modern sprockets they are are made of softer steel (which may bend rather than break if you shift under full power) and are as little as 1.6mm thickness. You won't be surprised to hear that I think they wear faster, and it is more important than ever that you don't run with a worn chain; if you do the sprockets wear to a bad shape more quickly.

cheers

Maybe it's the sprocket thing - I use 7 speed shimano now, but they are a lot thinner than the old Regina or similar. As for tooth hardening...… I rode a Suntour Winner freewheel (brand new) and before the week was out 2 teeth had snapped off one sprocket (I guess it was over-hardened?)

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Cassette question

Postby Brucey » 10 Oct 2019, 11:38am

fastpedaller wrote:
Brucey wrote:
Note that with 7s (BITD) the sprockets were 2mm thickness, and up to/including UG most sprockets were made of hard, relatively brittle steel that was relatively slow-wearing but would crack if you shifted clumsily under full power too often. With modern sprockets they are are made of softer steel (which may bend rather than break if you shift under full power) and are as little as 1.6mm thickness. You won't be surprised to hear that I think they wear faster, and it is more important than ever that you don't run with a worn chain; if you do the sprockets wear to a bad shape more quickly.

cheers

Maybe it's the sprocket thing - I use 7 speed shimano now, but they are a lot thinner than the old Regina or similar. As for tooth hardening...… I rode a Suntour Winner freewheel (brand new) and before the week was out 2 teeth had snapped off one sprocket (I guess it was over-hardened?)


Sometimes sprockets were just brittle (which is probably what happened in your case) but IME when teeth start breaking off it is often a sign of a badly worn chain or at least a chain that doesn't match the wear state of the sprocket(s) exactly. So it isn't unusual to find a freewheel with broken teeth on one sprocket, but it isn't always the most worn sprocket that breaks, it is often one of the neighbouring ones that doesn't match the worn chain so well. It may not be used so often but when it does it sees some very odd loads.

Modern 6s/7s freewheels are often built using sprockets that could instead be used in an 8s (or even 9s) systems, just spaced differently. These sprockets are thinner to start with (often 1.85mm or 1.9mm) and of course they become even thinner than that wherever there are shifting aids on the sprocket.

If you run a worn chain on a HG sprocket (that isn't so worn), the first tooth that wears will always be the thin one at the shift ramp.

Worth making the comment that (soft) HG sprockets do wear faster, but they probably keep their shape better too, even when worn; the shorter teeth don't so easily develop large hooks which are the biggest cause of skipping.

Any set of sprockets will wear to match the chain; its just how quickly this happens and whether or not they are liable to be damaged en route or not.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Marcus Aurelius
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Joined: 1 Feb 2018, 10:20am

Re: Cassette question

Postby Marcus Aurelius » 15 Oct 2019, 4:47am

531colin wrote:
Marcus Aurelius wrote:………. There is a saying ‘you can’t teach an old cog, new links’ which is very true, you’ll nearly always get some slipping, initially, when you don’t change cassettes and chains together, as the new pairing re mesh.......


Wrong.




It isn’t “wrong” I’m not arguing about it again.

Marcus Aurelius
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Re: Cassette question

Postby Marcus Aurelius » 15 Oct 2019, 4:48am

fausto99 wrote:
I also use an ultrasonic cleaner at every clean before I apply any more lubricant. A bit OTT I suppose but the geartrain and changes are so much smoother and more pleasant to use. I'm a happy bunny :lol: .



The ultrasonic baths are great things to have, they save a lot of chain / cassette wear, and faff.

Samuel D
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Location: Paris

Re: Cassette question

Postby Samuel D » 15 Oct 2019, 9:26am

Marcus Aurelius wrote:
531colin wrote:
Marcus Aurelius wrote:………. There is a saying ‘you can’t teach an old cog, new links’ which is very true, you’ll nearly always get some slipping, initially, when you don’t change cassettes and chains together, as the new pairing re mesh.......


Wrong.

It isn’t “wrong” I’m not arguing about it again.

At the very least, “nearly always get some slipping” is a great exaggeration. I nearly always don’t get slipping.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Cassette question

Postby Brucey » 15 Oct 2019, 10:33am

It all depends how worn the old chain was, how dimensionally correct the new chain is, and what the sprockets are like. In the worst case the cassette has been pedalled on in mostly just a few sprockets by a 'masher'; this causes much worse wear on the bad sprockets whereas a 'spinner' who uses all the sprockets more evenly will cause less severe wear even at the same %age elongation.

All these things together can make almost 0.5% difference in the acceptable wear state of the chain before a new chain will definitely slip under load. So nearly everyone will get away with changing the chain at 0.5% wear, but some people can let the chain wear to ~1% and they will still get away with it.

Different strokes for different folks; unfortunately you have to find out exactly what works for you.

FWIW it seems to me that old sprockets either retain their shape at least or are actually reshaped by being used with a newer chain. So if you can avoid pedalling hard enough to cause slipping, even worn cogs can be taught new tricks.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Marcus Aurelius
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Re: Cassette question

Postby Marcus Aurelius » 16 Oct 2019, 12:20am

Brucey wrote:It all depends how worn the old chain was, how dimensionally correct the new chain is, and what the sprockets are like. In the worst case the cassette has been pedalled on in mostly just a few sprockets by a 'masher'; this causes much worse wear on the bad sprockets whereas a 'spinner' who uses all the sprockets more evenly will cause less severe wear even at the same %age elongation.

All these things together can make almost 0.5% difference in the acceptable wear state of the chain before a new chain will definitely slip under load. So nearly everyone will get away with changing the chain at 0.5% wear, but some people can let the chain wear to ~1% and they will still get away with it.

Different strokes for different folks; unfortunately you have to find out exactly what works for you.

FWIW it seems to me that old sprockets either retain their shape at least or are actually reshaped by being used with a newer chain. So if you can avoid pedalling hard enough to cause slipping, even worn cogs can be taught new tricks.

cheers

Eventually the chain and cassette combo will re mesh, as long as the old cassette isn’t completely knackered, but unless you really are very careful, or you’ve been forced into an early chain change, or you’ve changed the chain, but it wasn’t particularly worn, you will get some slip, and that won’t do your new components any favours. Most people ( who aren’t just trying to be internet contrary Marys ) will get some degree of slip, if they don’t change cassettes and chains in unison. It’s not always a dead cert, but usually it’s fairly well expected.

Brucey
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Re: Cassette question

Postby Brucey » 16 Oct 2019, 12:34am

Marcus Aurelius wrote:…. Most people ( who aren’t just trying to be internet contrary Marys ) will get some degree of slip, if they don’t change cassettes and chains in unison. It’s not always a dead cert, but usually it’s fairly well expected.


I think there are enough people happily changing chain only, early enough that the 'Most people' and 'well expected' comments are not justified. What 'Most people' is that anyway? Most people that try, most people that plan to change the chain only , or just most people that ride a bike, any old bike, with any old lack of attention to chain wear?

There are plenty of strategies that can work; for example you could change three chains in a row at 0.3% and you definitely wouldn't get any skipping with a new chain, no matter how horrible a masher you are. Yet you have lost nothing; these chains can be used again from 0.3% to 0.6% and then given a third turn 0.6% to 0.9% if you like. There won't be any skipping. I wonder just how many chains you could run in the same way; three, four, five, six... or more?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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Cugel
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Re: Cassette question

Postby Cugel » 16 Oct 2019, 9:36am

Brucey wrote:
Marcus Aurelius wrote:…. Most people ( who aren’t just trying to be internet contrary Marys ) will get some degree of slip, if they don’t change cassettes and chains in unison. It’s not always a dead cert, but usually it’s fairly well expected.


I think there are enough people happily changing chain only, early enough that the 'Most people' and 'well expected' comments are not justified. What 'Most people' is that anyway? Most people that try, most people that plan to change the chain only , or just most people that ride a bike, any old bike, with any old lack of attention to chain wear?

There are plenty of strategies that can work; for example you could change three chains in a row at 0.3% and you definitely wouldn't get any skipping with a new chain, no matter how horrible a masher you are. Yet you have lost nothing; these chains can be used again from 0.3% to 0.6% and then given a third turn 0.6% to 0.9% if you like. There won't be any skipping. I wonder just how many chains you could run in the same way; three, four, five, six... or more?

cheers


I learnt decades ago to change a chain well before it "stretches" to a condition that will affect the cog teeth of sprocket or chainring. At the same time, I learnt to keep the chains clean and well lubricated in use. I rotate lots of them to keep them so. Perhaps as a result I can't remember when I last wore out a freewheel or cassette sprocket. I did wear out some Shimano biopace chain rings once but I believe this was because they were made of silver-coloured cheeses. :-)

I am a spinner, mind - although in days of yore I also heaved as the 42X21 was the lowest gear and one did have to traverse various Pennines, Howgills and lumps of Lakeland at 41rpm whilst weaving across the road sine wave fashion.

I have a meme that dictates behaviours that tend to preserve things. This meme is part composed of another (being too mean to waste money) and yet another (being conservative, in the literal sense). I was recently bereft when a 15 year-old computer power supply went bang and proved unfixable.

Cugel

Marcus Aurelius
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Re: Cassette question

Postby Marcus Aurelius » 18 Oct 2019, 11:34am

Brucey wrote:
Marcus Aurelius wrote:…. Most people ( who aren’t just trying to be internet contrary Marys ) will get some degree of slip, if they don’t change cassettes and chains in unison. It’s not always a dead cert, but usually it’s fairly well expected.


I think there are enough people happily changing chain only, early enough that the 'Most people' and 'well expected' comments are not justified. What 'Most people' is that anyway? Most people that try, most people that plan to change the chain only , or just most people that ride a bike, any old bike, with any old lack of attention to chain wear?

There are plenty of strategies that can work; for example you could change three chains in a row at 0.3% and you definitely wouldn't get any skipping with a new chain, no matter how horrible a masher you are. Yet you have lost nothing; these chains can be used again from 0.3% to 0.6% and then given a third turn 0.6% to 0.9% if you like. There won't be any skipping. I wonder just how many chains you could run in the same way; three, four, five, six... or more?

cheers

By the time you’ve done that, you’ve ( usually IME ) spent more than if you’d let the chain go to a point where you really should be changing it, and doing the cassette at the same time.

Brucey
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Re: Cassette question

Postby Brucey » 18 Oct 2019, 12:34pm

Marcus Aurelius wrote:

There are plenty of strategies that can work; for example you could change three chains in a row at 0.3% and you definitely wouldn't get any skipping with a new chain, no matter how horrible a masher you are. Yet you have lost nothing; these chains can be used again from 0.3% to 0.6% and then given a third turn 0.6% to 0.9% if you like. There won't be any skipping. I wonder just how many chains you could run in the same way; three, four, five, six... or more?


By the time you’ve done that, you’ve ( usually IME ) spent more than if you’d let the chain go to a point where you really should be changing it, and doing the cassette at the same time.


The chains wear at about the same rate as they would anyway (for any given cleaning regime), so if you run three chains in rotation like that to 1% then you get about the same mileage as x3 cassettes each with one chain to 1%, only you have saved the cost of two cassettes. [If you run longer than 1% then the chainrings really start to suffer. Running even one chain to 2% usually destroys aluminium chainrings.] In point of fact you might get more mileage than that because

a) only a real twit would take chain off and then not bother cleaning it, whereas it is easy to leave one on the bike dirty and
b) with chain rotation, at any given time there is likely to be a smaller mismatch between the chain and the cassette; worn chains wear the cassette worst and with a single chain on a given cassette the chain is always 'further ahead of' the cassette in wear terms.

If your cassettes cost about the same as chains do then there is relatively little to be gained perhaps, but IME this is rarely the case. In extremis you can be running an 11s cassette which costs ~£200 using chains which cost less than ten quid each. Chain breaks or goes rusty? No problem, provided you change it before it gets too worn.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Cassette question

Postby Brucey » 11 Feb 2020, 10:50pm

fastpedaller wrote:
Brucey wrote:
Note that with 7s (BITD) the sprockets were 2mm thickness, and up to/including UG most sprockets were made of hard, relatively brittle steel that was relatively slow-wearing but would crack if you shifted clumsily under full power too often. With modern sprockets they are are made of softer steel (which may bend rather than break if you shift under full power) and are as little as 1.6mm thickness. You won't be surprised to hear that I think they wear faster, and it is more important than ever that you don't run with a worn chain; if you do the sprockets wear to a bad shape more quickly.

cheers

Maybe it's the sprocket thing - I use 7 speed shimano now, but they are a lot thinner than the old Regina or similar. As for tooth hardening...… I rode a Suntour Winner freewheel (brand new) and before the week was out 2 teeth had snapped off one sprocket (I guess it was over-hardened?)


Could be, (I've seen a few broken steel sprockets) but then again might it have been an aluminium sprocket?

From ~1975 to ~1978 SunTour's 'Winner' freewheel was available in two basic types, each in 5 or 6s form. The 'Winner S' had steel sprockets and the 'WInner' (no 'S' suffix) had hard aluminium sprockets, and was primarily intended for racing. The aluminium sprockets turned out not to be up to hard service and were abandoned when the 'New Winner' was introduced (late 1978 I think). Sun Tour tried again with an aluminium freewheel in the 1980s, but I think that they only listed it for a couple of years before it was quietly withdrawn.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~