Cassette question

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mtbsteve1981
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Joined: 7 Oct 2019, 9:36am

Cassette question

Postby mtbsteve1981 » 8 Oct 2019, 8:37am

Hi all,
I have heard that you should change the cassette every 2 chains assuming you change the chain at the recommended point of wear. Is this right or do you generally run it until you get chain skip?

I would like to hear people's thoughts on this.

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Paulatic
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Re: Cassette question

Postby Paulatic » 8 Oct 2019, 8:42am

mtbsteve1981 wrote:Hi all,
I have heard that you should change the cassette every 2 chains assuming you change the chain at the recommended point of wear. Is this right or do you generally run it until you get chain skip?

I would like to hear people's thoughts on this.

I run them until the skip doesn’t disappear after ~50 miles with the new chain.
Always been more than 2 chains and sometimes after a full 1% of chain wear.
Whatever I am, wherever I am, this is me. This is my life

https://stcleve.wordpress.com/category/lejog/

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Cassette question

Postby Brucey » 8 Oct 2019, 8:57am

I think the approach above is a very pragmatic one; I often do something similar.

Its worth noting that there are no exact hard and fast rules here; folk (with chains at the same elongation) won't produce exactly the same wear patterns in the cassette, and won't necessarily suffer skipping with a new chain even if they do. It depends how hard you push on the pedals and which sprockets you favour.

Also, new chains vary. Most are close to exactly 0.500" pitch but are usually slightly over (by 0.05% to 0.1%) once they have been run a few miles and most of the grease has been pushed out of the bushings. So some chains skip to start with but this soon disappears. Others can take much longer to settle down, requiring some degree of

a) sprocket wear and/or
b) chain elongation

before running will be 100% skip-free.

It occurs to me that at least one of my favoured gear setups has enough duplication in the ratios that in the 'tapping along' ratios the wear might be spread over more sprockets than might be found in other gear setups. This may make it less likely that any one sprocket is likely to be very badly worn.

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

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

Re: Cassette question

Postby Marcus Aurelius » 8 Oct 2019, 10:26am

If I really want it running perfectly, I change chain and cassette, and chain rings, and jockey wheels at the same time. However, that’s expensive, and not strictly necessary. But I will ( nearly ) always change the cassette and chain at the same time, unless a chain replacement is necessitated by a very premature chain failure. 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. This initial slipping can end up prematurely wearing the new components ( depending on how bad the slippage is, and for how long it goes on ) which can make the ‘changing one, but not the other’ a bit of a false economy.

KM2
Posts: 397
Joined: 23 Oct 2008, 5:38pm

Re: Cassette question

Postby KM2 » 8 Oct 2019, 1:19pm

If you rotate your 2 or 3 chains each month, they’ll all, and the cassette need changing together. When the chains are over length. A worn chain is likely to wear the cassette faster.

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531colin
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Location: North Yorkshire

Re: Cassette question

Postby 531colin » 8 Oct 2019, 5:58pm

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. If you change the chain before it has worn the teeth to change the tooth profile, you won't get any skipping.
We had this discussion before https://forum.cyclinguk.org/viewtopic.php?f=5&t=116834&hilit=cassette&start=15, and since then my cassette dating from 2011 has survived another winter.

NetworkMan
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Joined: 25 Aug 2014, 11:13am
Location: South Devon

Re: Cassette question

Postby NetworkMan » 8 Oct 2019, 6:29pm

8 and 9 speed chains are cheap and tedious to clean so I tend to change them at 0.5% elongation or less. Cogs and rings seem to last well. Rotating chains? Not for me - too much bother!

Valbrona
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Re: Cassette question

Postby Valbrona » 8 Oct 2019, 8:09pm

Never trust a chain wear checker. Flawed thinking.
I should coco.

keyboardmonkey
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Location: Yorkshire

Re: Cassette question

Postby keyboardmonkey » 8 Oct 2019, 8:20pm

NetworkMan wrote:8 and 9 speed chains are cheap and tedious to clean so I tend to change them at 0.5% elongation or less. Cogs and rings seem to last well. Rotating chains? Not for me - too much bother!

+1

tmac100
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Re: Cassette question

Postby tmac100 » 8 Oct 2019, 8:23pm

Valbrona wrote:Never trust a chain wear checker. Flawed thinking.

What do you base this statement on?

mtbsteve1981
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Joined: 7 Oct 2019, 9:36am

Re: Cassette question

Postby mtbsteve1981 » 8 Oct 2019, 8:34pm

Wow some interesting answers. I had a bike for years that i commuted on daily and never thought to change the chain once.

Now im more into cycling, i like to keep them as well as i can. Its good to hear that i can save money changing the chain sooner. I guess that makes sense as the chain will be in the ideal shape most of the tine and be unable to wear the sprockets too badly

MikeF
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Re: Cassette question

Postby MikeF » 8 Oct 2019, 10:36pm

There are some who are fastidious about changing and cleaning chains and some who are not. However 8 speed chains are cheap whereas higher speed chains can be quite dear so it's a bit horses for courses. I usually change a chain (8 speed) when it's about 0.5%-0.75% worn, but I'm not fastidious. :lol:
"It takes a genius to spot the obvious" - my old physics master

hamster
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Re: Cassette question

Postby hamster » 9 Oct 2019, 8:00am

Valbrona wrote:Never trust a chain wear checker. Flawed thinking.


Yes, I prefer to hold a crystal near my chain. :lol:

Samuel D
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Re: Cassette question

Postby Samuel D » 9 Oct 2019, 9:59am

The reason most chain wear indicators are not as useful as they should be is described here. Essentially they measure the wrong thing. For this reason I prefer a ruler.

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531colin
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Location: North Yorkshire

Re: Cassette question

Postby 531colin » 9 Oct 2019, 5:26pm

Samuel D wrote:The reason most chain wear indicators are not as useful as they should be is described here. Essentially they measure the wrong thing. For this reason I prefer a ruler.

Pedant alert; I would agree that (most) chain wear gauges are not as accurate as they could be because the "wear" they measure includes the "wrong sort of wear". So that if you were determined to wring the last drop of use out of your chain before you binned it, then a wear gauge could be pessimistic, ie it might tell you to replace the chain before it was absolutely worn out.
However, I include "usability" in my definition of "useful". My chain wear gauge is highly usable. I just go into my cold, dark garage and drop the gauge onto the chain, at a number of points. I don't get my hands dirty, and I don't have to take the chain off, or clean it, or anything like that. I don't even have to find my reading glasses.
I'm prepared to accept that I chuck chains away before I really absolutely have to, but 8 speed chains are so cheap that I can't be bothered to clean and mess about with them anyway. I have cassettes in use which I have been using since 2011 and chainrings which are getting on to be old enough to vote.