Author Topic: Cassette wear – how many chains?  (Read 1333 times)

Re: Cassette wear – how many chains?
« Reply #25 on: October 11, 2018, 11:44:54 am »
Hooks on teeth are obvious but they don't exist without a 'ramp' developing too. The ramp leads from the well between teeth into the hook.

Would you confirm this is roughly what you mean by those terms?



The skipping of the chain at the rear is due to the chain failing to engage with the sprocket as it leaves the guide pulley. It is fairly obvious that a hook can obstruct the chain engagement. What is less obvious is that the ramps can push loaded rollers further outwards on the tooth profile than normal, and this causes the chain to be tight against the teeth where the pitch is longer than the pitch of a less worn chain. In this case the chain won't engage even though there is no obvious 'hook'.

Right. I’ve observed that hooks aren’t strictly necessary to cause the problem, especially, it seems, with small sprockets. And yet the longer pitch of a worn chain would seem, from basic geometry, to increase the chain’s ride height less on smaller sprockets than on bigger ones, in absolute terms (and more importantly, relative to the fixed tooth height). So it’s still slightly surprising to me that small sprockets so readily cause skipping.

Re: Cassette wear – how many chains?
« Reply #26 on: October 11, 2018, 12:09:01 pm »
All the same, Shimano recently purged a bunch of 7-speed cassettes (good road-focused ones).
Road-focussed might be the long-term problem. As 8-speed and pretty soon 9-speed slip down the hierarchy, they will cease appearing on new road bikes and only be found on cheaper hybrids and MTBSOs. The Diverge I mentioned is a sort of "gravel bike" (friend uses it for long on- and off-road randonnee type rides) so falls into the gaps Shimano have created between road and mountain.
The earth is vast and beautiful and contains many miraculous places. (Chekhov)

LittleWheelsandBig

  • Whimsy Rider
Re: Cassette wear – how many chains?
« Reply #27 on: October 11, 2018, 12:56:29 pm »
Yeah, I noticed it, I bolded it.

I view modern Campag as being inferior to Shimano in terms of owning and maintaining it (as you know). The stuff I drooled over in the 80s but could never afford was akin to Leica in terms of quality.

WAP doesn't pick up bolded text.

I wholeheartedly agree about modern Campag. vs. older. They've systematically removed every single reason to choose it over Shimano, hence the reason that HK's newest machines have completely avoided Campag. I don't see that situation changing back.
Wheel meet again, don't know where, don't know when...

Re: Cassette wear – how many chains?
« Reply #28 on: October 11, 2018, 01:00:04 pm »
I think I probably achieved top chain wear classification when I was doing my cross London Commute a few years ago. I tried all manner of lubricants and regimes and settled on change chain and cassette every two chains. Possibly a bit excessive but it kept everything running sweetly and 9 speed chains and cassettes could be had cheaply

Re: Cassette wear – how many chains?
« Reply #29 on: October 11, 2018, 01:08:13 pm »
Road-focussed might be the long-term problem. As 8-speed and pretty soon 9-speed slip down the hierarchy, they will cease appearing on new road bikes and only be found on cheaper hybrids and MTBSOs.

Claris and Sora (8 and 9 speed) both got complete redesigns in 2016 so are good for a few years yet. In fact, Shimano used the same speed count for all of the last round of redesigns - nothing moved down the hierarchy.

And as they all now all use very similar designs they don’t really have any other way to differentiate them, and there’s no road 12 speed coming in from the top to push others down, I can see them sticking with the current setup for a while.

Re: Cassette wear – how many chains?
« Reply #30 on: October 11, 2018, 01:39:39 pm »
Yeah, I noticed it, I bolded it.

I view modern Campag as being inferior to Shimano in terms of owning and maintaining it (as you know). The stuff I drooled over in the 80s but could never afford was akin to Leica in terms of quality.

WAP doesn't pick up bolded text.

I wholeheartedly agree about modern Campag. vs. older. They've systematically removed every single reason to choose it over Shimano, hence the reason that HK's newest machines have completely avoided Campag. I don't see that situation changing back.

I don't blame them, it's just what they have to do to compete. Outsource production, and come up with poor design solutions to the problem of not infringing Shimano patents.

The problem for them is that Shimano do what they do very very well.

I don't know much about SRAM.

Re: Cassette wear – how many chains?
« Reply #31 on: October 11, 2018, 01:49:47 pm »
Claris and Sora (8 and 9 speed) both got complete redesigns in 2016 so are good for a few years yet.

The recent batch of ‘Claris’ cassettes isn’t ideal for me though, because they all waste metal on 11T sprockets.

All I need for long-term use of 8-speed is a supply of suitable cassettes. My indexed down-tube shifters last a very long time, don’t get damaged in crashes, and I have four pairs in reserve (got nearly for free in a close-out sale). Loads of rear hubs work (unlike for 7-speed). Loads of derailleurs have the right shift ratio, even if they’re not labelled 8-speed (I currently use a 10-speed RD-7800, for example). Loads of chains work whatever their speed label. Loads of chainrings work, and my Spécialités T.A. ones wear very slowly anyway.

Part of my interest in this experiment was to find out how many cassettes I might need for, say, three decades of cycling. By then, as a friend remarked, I might want something cushier than 26T for a low gear (depends where I live then).

Low running costs are an essential part of the freedom of cycling.

CrazyEnglishTriathlete

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Re: Cassette wear – how many chains?
« Reply #32 on: October 11, 2018, 01:58:58 pm »
In summer, I do.

I did note 'older Campag'. The modern Campag rings I've used are made of mozzarella.

It would be great if cycling magazines started talking about how long things lasted rather than how light they were.  However, I suspect that if they revealed the great fraud of modern cycle components (that things wear out quicker) they'd quickly lose all their advertising revenue.
Eddington Numbers 122 (imperial), 165 (metric) 510 (furlongs)  110 (nautical miles)

LittleWheelsandBig

  • Whimsy Rider
Re: Cassette wear – how many chains?
« Reply #33 on: October 11, 2018, 02:41:10 pm »
Some magazines used to do long-term tests but the riders didn't do enough mileage to talk sensibly about durability before the model was superseded, starting the whole cycle again. I noticed that any deficiencies of a particular model were only mentioned when the subsequent model was released (which obviously solved those problems).
Wheel meet again, don't know where, don't know when...

Re: Cassette wear – how many chains?
« Reply #34 on: October 11, 2018, 03:14:06 pm »
Do many high mileage cyclists read cycling mags?
Most of them are pretty poor. Recycled training articles and reviews written by people who don't really know much. I always giggle when I see journos talking about certain wide and deep carbon wheels definitely feeling faster. Light wheels feel fast to me, but the main advantage of deep carbon wheels is that they make a really cool veeeeeerp sound as you ride along.

Why do mags never mention this key selling point?

LittleWheelsandBig

  • Whimsy Rider
Re: Cassette wear – how many chains?
« Reply #35 on: October 11, 2018, 03:17:04 pm »
My annual mileage isn't that high but we subscribe to several cycling mags, though one subscription will lapse in February. I eventually couldn't put up with the depth of bullshit created from trivial riding and advertorial puffpieces. HK thinks that most mags are a waste of space.
Wheel meet again, don't know where, don't know when...

Re: Cassette wear – how many chains?
« Reply #36 on: October 11, 2018, 03:29:32 pm »
Samuel's had to scrap a cassette because two of the sprockets were worn. The other six were still good – that's 75% good, but the whole cassette is scrap! And of course that's the way it always is – the one or two sprockets we use most get worn and the rest are still good. Suddenly I see the point of those combine-your-own-cassette services from, I think, Miche. It's not so much that you get the ratios you pick, it's that you can replace one sprocket at a time. Yes, I know some people do this by dismantling standard sprockets, but then you end up with a pile of sprockets which are all the ones you don't use.

Something like this: https://thecycleclinic.co.uk/products/miche-11-speed-for-shimano-individual-cassette-sprockets
The earth is vast and beautiful and contains many miraculous places. (Chekhov)

Re: Cassette wear – how many chains?
« Reply #37 on: October 11, 2018, 04:08:47 pm »
Having only one cassette roadwheel in the fleet (the rest are either scew-on in a mixture of french and english threads or mtb cassette wheels) i think the only 8sp road cassettes that interest me will have ceased to be available long before I have used up my box of Maillard and Sachs ARIS sprockets. Only problem could be a shortage of french freewheel bodies since the old Mavic hubs last forever and a day (as do the sprockets)!

re gravel bikes and Claris I have been looking around (only windowshopping of course  ;) ) and it appears that a number of manufacturers have a Claris equipped model at the entry level. There is quite a price difference compared to the first 9sp models (Sora I think). The Diverge is one such, there are others.

Re: Cassette wear – how many chains?
« Reply #38 on: October 11, 2018, 04:28:44 pm »
Unless I’ve missed it there’s been no mention on this thread of rotating chains to get more out of each chain and cassette. Does that mean I’ve been slavishly adhering to a cycling club urban myth all these years?

(i.e. start with new chain & new cassette / at half-life replace part-worn chain 1 with new chain 2 / at end-of-life discard chain 2 and replace with part-worn chain 1 / run until end-of-life and then replace both chain & cassette.)
R10000 x 2   RRtY x 6    SR x 7    E = 127

Re: Cassette wear – how many chains?
« Reply #39 on: October 11, 2018, 04:41:36 pm »
Sounds extraordinarily like a more complicated version of my two chains/1  cassette.

Re: Cassette wear – how many chains?
« Reply #40 on: October 11, 2018, 05:39:12 pm »
Unless I’ve missed it there’s been no mention on this thread of rotating chains to get more out of each chain and cassette. Does that mean I’ve been slavishly adhering to a cycling club urban myth all these years?

(i.e. start with new chain & new cassette / at half-life replace part-worn chain 1 with new chain 2 / at end-of-life discard chain 2 and replace with part-worn chain 1 / run until end-of-life and then replace both chain & cassette.)
Needs an accurate way of measuring half-life.
The earth is vast and beautiful and contains many miraculous places. (Chekhov)

Re: Cassette wear – how many chains?
« Reply #41 on: October 11, 2018, 05:42:55 pm »
there's a good case for a single speed setup if one's bulk of the mileage is on flat(ish) terrain - better efficiency, reliability, easier cleaning, lighter, cheaper to run. big part of commuters i see in london don't bother changing gears anyway.

Re: Cassette wear – how many chains?
« Reply #42 on: October 11, 2018, 05:47:21 pm »
I've used a new cassette (9spd 11 to 34) about every 6 chains.

Re: Cassette wear – how many chains?
« Reply #43 on: October 11, 2018, 06:01:03 pm »
I've used a new cassette (9spd 11 to 34) about every 6 chains.

That’s a good cassette life. How are you measuring your chain?

On another forum, 531colin (designer of the Spa Cycles frames) reports going through about nine chains on his current cassette … and it’s still going. He’s measuring with some sort of wear gauge so probably changes chains a bit earlier than I do.

That thread, by the way, has an intriguing reverse-wear method from Brucey. Probably too much work for me in practice, but a nice thought exercise.

Re: Cassette wear – how many chains?
« Reply #44 on: October 11, 2018, 06:06:30 pm »
there's a good case for a single speed setup if one's bulk of the mileage is on flat(ish) terrain - better efficiency, reliability, easier cleaning, lighter, cheaper to run. big part of commuters i see in london don't bother changing gears anyway.

I often do hilly rides in the Chevreuse Valley area, but if I ever have two bicycles, one will be a single-speed. In riding with others on single-speeds (actually, most of them are fixed-gear machines), I have noticed that most of them are noisy … intolerably noisy. I wonder what they’re doing to these poor things to get them to sound like that. Still, their riders sound happy!

Re: Cassette wear – how many chains?
« Reply #45 on: October 11, 2018, 06:12:00 pm »
Chain too tight or loose and/or poor chainline.


Re: Cassette wear – how many chains?
« Reply #46 on: October 11, 2018, 06:21:21 pm »
yes, correctly set up and maintained drivetrain should be inaudible.

Re: Cassette wear – how many chains?
« Reply #47 on: October 11, 2018, 06:22:15 pm »
I've used a new cassette (9spd 11 to 34) about every 6 chains.

That’s a good cassette life. How are you measuring your chain?

With one of these https://www.sjscycles.co.uk/tools/park-tool-cc32-chain-wear-indicator/
changing the chain as soon as I notice that it's gone past 0.5%. Which is around 2400 miles +/- 30%.

Thanks for that link!

Re: Cassette wear – how many chains?
« Reply #48 on: October 12, 2018, 09:05:21 am »
there's a good case for a single speed setup if one's bulk of the mileage is on flat(ish) terrain - better efficiency, reliability, easier cleaning, lighter, cheaper to run. big part of commuters i see in london don't bother changing gears anyway.

I often do hilly rides in the Chevreuse Valley area, but if I ever have two bicycles, one will be a single-speed. In riding with others on single-speeds (actually, most of them are fixed-gear machines), I have noticed that most of them are noisy … intolerably noisy. I wonder what they’re doing to these poor things to get them to sound like that. Still, their riders sound happy!

A SS setup is usually very quiet when the parts are new; however once the chain is a little worn there is a conflict between elimination of slack and the need to let the chain 'ride out' on the chainwheel teeth, I.e. to the diameter at which the (longer) chain pitch matches  the pitch of the teeth.

If the slack is removed from a slightly worn chain (leaving (say) a nominal 1/2" free play) then the transmission can become very noisy. It is also likely to be wearing very quickly too, since the loads cannot be shared between teeth in the normal way. Any time such a  transmission is noisy, it is very likely that the chain rollers are  moving around on the teeth whilst under load, which causes everything to wear more quickly than normal.

The only situation where I will tolerate noise for any length of time is when  I have let a chainring become slightly hooked, and it is being forced to mate with a new chain. It rarely takes more than a few hundred miles to go quiet.

IME if everything is allowed to wear together, and enough slack is allowed/tolerated (i.e. without unshipping) a SS/IGH transmission remains quiet and smooth even when the chain is worn to ~1.5%. It ain't a smart idea to run chains out this far if you don't have a steel chainring though; the chainring gets into a pretty bad state otherwise.  Presumably there is some loss of efficiency through running with a worn chain but this (unlike noise) usually isn't noticeable.  When everything is knackered, a  new chain and sprocket (less than ten quid for an IGH....) and you are good for another few thousand miles.

However do note that on a fixed gear setup any chain slack is not usually tolerated; for one thing the chain is very likely (more likely than with a freewheel) to unship and for another the sensation of a slack chain with a fixed gear is pretty nasty. Some riders like the feeling of a slack chain less than the noise, so they choose to have noise.  Note that running a really quiet fixed gear setup is not a cheap business; good fixed sprockets are quite expensive and even if they are evenly worn (i.e not hooked, run smoothly under load still) any wear on the sprocket also generates a small amount of backlash, because the chain rollers are no longer located positively between the teeth. SS freewheel and IGH setups are a lot more tolerant of chain/sprocket condition.

BTW thanks for putting the arrows and labels on your photo; it is exactly as you indicate.  FWIW I can usually spot hooks that are bad enough to cause skipping but ramps are more subtle. It is clear that the difference between a tooth shape that will cause skipping and one that won't can be as little as about 10 microns of metal in the wrong place.

One of my mad ideas is that if you have a couple of ramped sprockets that won't play ball with a new chain, it might be that they can be 'shown who is boss' by being used in a (tensioner-less) SS setup for fifty (slightly noisy) miles or so. You could keep a new chain for this exact purpose, perhaps.

Having run a few different systems over the years (maillard freewheels, sun tour freewheels, shimano UG, shimano HG, etc) the same thing happens with all of them; you run out of the sprockets that you use most/wear fastest before any of the others.

 Some sprockets

a) are favoured and see more use than the others and/or
b) are small-ish so wear more quickly anyway and/or
c) appear in every freewheel/cassette you might build (eg if you use the same system for racing and touring)

so with my sun tour 'New Winner' freewheels (BITD I was a sucker for more cogs; I was running 7s in ~1979, i.e. five years before it was available in Dura-Ace) I basically ran out of 15T and 17T sprockets first.  They say the only certainty is change; for a few years there were three bike shops I could go to which each had a fully loaded Sun Tour sprocket board and I could keep things sweet and have the exact ratios I wanted by just buying a few extra sprockets.

With a shimano 8s cassette system you could perhaps use odd UG sprockets in the most-used positions. These sprockets are reversible so you can get extra life out of them. Gawd knows where you would get them now though. Other options include shimano DX BMX sprockets eg
https://www.bike24.com/p217742.html
 and Brompton 6s sprockets/SA S3X sprockets (both found  on this page)
https://www.sjscycles.co.uk/sprockets-hub-gear/?page=2

both of which use a modified freehub spline design and are available in 3/32" format. Again some of these (with a small spline modification) are reversible.

  If you start using odd sprockets in an HG cassette then shifting performance is likely to be degraded; you may or may not tolerate this.

cheers





Re: Cassette wear – how many chains?
« Reply #49 on: October 12, 2018, 10:31:26 am »
I've used a new cassette (9spd 11 to 34) about every 6 chains.

That’s a good cassette life. How are you measuring your chain?

With one of these https://www.sjscycles.co.uk/tools/park-tool-cc32-chain-wear-indicator/
changing the chain as soon as I notice that it's gone past 0.5%. Which is around 2400 miles +/- 30%.

Thanks for that link!

FWIW that chain checker (like most) is slightly pessimistic in some cases because it includes an element of roller wear in the overall measurement. Thus chains which wear the roller bushings quickly (more quickly than they 'stretch') may be condemned before their time. Colin uses a similar tool, and knows that he slings some chains a little before their time. But he argues that slinging a chain that cost him £4 or so a couple of hundred miles before its time is no great hardship, and I think he is right.

cheers