A couple of ‘technical’ questions! (Is Brucey around?) How many chain replacements to a cassette/chainring change? ie assuming that they last longer than one chain. Also, any guide as to how long a chain should last, appreciate that there is no such thing as average, but, ‘old bloke on a 12 speed mtb riding roads and paths!’ ie, not abusing it. Suggestions on a postcard please
Last edited by Graham on 24 Nov 2020, 11:50am, edited 1 time in total.
Reason:Title
Never attribute to malice that which is adequately explained by stupidity
If you have one cassette and 3 chains, then rotate the chains each month, making sure they are cleaned when off the bike. They will last much longer. Failing that, do keep them clean and replace before totally worn. Buy a chain wear indicator.
Riding on rural roads near you we get about 8k/10k miles from an 8 speed cassette and 2 kmc z51 chains per cassette, on our Tandem, we rotate and clean the chains every 500 miles. Chainset with steel rings lasts approx 30k miles. Fortunately we don't use the main road much so avoid the salt.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway X2, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840
needless to say not every chain, sprocket set or chainring set are
a) made as well as one another b) see the same service loads c) see the same service conditions d) see the same maintenance regime.
Also the wear rate varies with how worn the parts already are. So for example running a chain from 0 to 0.5% is likely to do much less damage (to the chainrings and sprockets) than running the chain from 0.5% to 1%, even though the latter part of the chain life might occur over about one third the total mileage.
So really it is a bit like asking 'how long is a piece of string'...?
An interesting anecdote; commonly used chains will have a life that varies with conditions of use. One common model of chain has recently been reported to have a mileage of 8000 miles (to 0.75% wear) by one forum member here. I have also seen that identical model of chain last just 200 miles. In the latter case it was horribly abused, in a very special way. But this was just a mistake on the part of the person that rode the bike; their 'improved maintenance regime' resulted in the bushings running bone dry and they not only didn't realise this, they thought the chain 'must be faulty' and took it back to the shop where they bought it.
I have personally found that transmissions that get dirty can last up to four times longer if they are cleaned regularly; on a MTB cleaning can be as often as every day.
So anyway chain rotation and changing chains early (before they have a chance to wear the sprockets and chainrings) are both excellent ways of increasing the life of the whole transmission. Used chains (with ~0.5% wear in them) can be 'used again' if you want when the rest of the transmission is badly worn and headed for the bin anyway.
Funnily enough, I've just changed my cassette (11Speed 105) after an estimated 18,000 miles. I haven't noticed much difference in the gear changes as a result. Chainrings are OK. I change chains at 0.5% and they last 2,500 to 3,000 miles. I wax my chains. The idlers on the Ultegra 6800 rear mech were worn out and there is some play in the mech itself - despite lubricating it frequently. When I start using my winter bike I'll check and change anything worn. Other items I've changed are the wheels after about 13,000 miles when the brake tracks wore out and the BB (Push in type) after about 16,000 miles. Oh, and the bar tape is on its last legs. Otherwise it's on its fourth set of tyres after about 20,000 miles.
Many thanks for great responses, so helpful! Confirmed what I suspected, think I need to get another chain gauge and reassess wear. Mine is .75 - 1.0 % and I’ve changed the chain when between the two. Would everyone agree that I should bin anything over .5 to maximise cassette life?
Never attribute to malice that which is adequately explained by stupidity
This link will take you to the end of a long thread about chain/sprocket wear https://forum.cyclinguk.org/viewtopic.php?f=5&t=116834&hilit=cassette&start=30 The cassette in the photos still takes a new chain without skipping; its obviously worn but the tooth profile must be OK. That cassette came into use on my winter bike no later than 2011. Its seen a lot of chains, I chuck 8 speed chains away before the wear gauge tells me to. I have chainrings in use which must be old enough to vote!
I reckon on 500-3000 miles on a 7/8 speed MTB chain, depending massively on riding location and weather. Typically I'll get through 3-10 chains before needing to replace the cassette. I use a Park chain tool to check wear, and run a chain up to 1%.
The cassette on my best road bike has lasted an absurd length of time, at least 40,000 miles now, maybe as much as 50,000. I'm not terribly fastidious about cleaning it but I do change the chain very regularly and don't ride it when the roads are wet or dirty (I have other bikes for that). The cassette itself is interesting and unusual. It's made in Canada by the now defunct Cycle Dynamics. The plus point is it's not stamped, it's properly gear cut which gives a more accurate tooth profile which extends its life. The minus is it's titanium which should last less long, but it seems accurate manufacturing and regular chain replacement outweighs that.
Most of my other bikes have a variation on this theme. I'm never happy with stock cassettes so over the years I've bought various non-standard Marchisio cassettes, a job lot of Mavic M10 when they ceased production and sundry other cassettes which I've split into individual sprockets and a few individual sprockets to fill gaps. That means I almsot never buy a cassette as such, I build them up out of individual sprockets to suit and any worn ones get replaced individually, but my policy of changing chains very regularly means I rarely wear any of them out.
I've done this for systems of 7 - 10 speed. I don't really know how it would work on 11 and I suspect 12 wouldn't be possible.
It depends how you maintain / use them, as much as on the quality of the components. ‘Chain stretch’ is actually only ‘effective’ chain stretch. What’s actually happening is that the rollers in the links are wearing down, which gives the impression that the chain has elongated. The distance between the centres of the rivets actually hasn’t changed ( or by an insignificant amount ). The side plates of the links can thin out a bit as well, leading to ‘slop’ but that’s harder to measure / quantify. If you keep the drive train cleaned and lubed adequately, and don’t mess shifts up, you’d be surprised how long you can keep a chain and cassette going.
Have tended to use 3 chains changing them every 1k miles, but hasn't always resulted in a lack of chain skipping when the original is put back on after 4k miles (the 3rd chain does 2k miles, as each subsequent chain will do), so I think the elongation-based criterion is more rational than a fixed mileage interval.
Will be using 0.5% elongation as a suitable chain swap criterion from now on. Chain gauges are also not to be trusted as is mentioned somewhere in that long thread - better to measure between link pins using a ruler with the chain hung up or otherwise placed in tension.
currently rotating 8 chains on the same 7 speed cassette, took them all out to 0.75, and now going back through them taking them out to 1.25 (think I still have two at 0.75) Cassette is looking a bit hard up, I have had to reverse two of the cogs as they started skipping, (reversing them seems to cure them LOL) Think the cassette is approach 20,000 miles. I must work it out exactly, could ring a bell when it passes that milestone.
A font of information! Thanks everybody - will try to ‘experiment’. I only started to wonder, after I replaced a chain that measured between .75 and 1, and the new one started ‘jumping’ on the two highest gear cogs. This I deduced was because these would have suffered from wear first having fewer teeth? I have a vernier gauge and steel rule, so will experiment. One further question - assuming that wear is a continuous process, ie something has ‘got to give’ in any mechanical contact situation, surely swapping chains with varying degrees of wear will still degrade the cassette/chainring over time? Or, does it just delay the inevitable? Is the answer to end up with a selection of evenly worn components, and ‘run them into the ground’?
Never attribute to malice that which is adequately explained by stupidity
slippage (skipping) on the smallest sprockets with a new chain is indeed quite common; not only do these sprockets wear fastest (for any degree of use) but because the chain wrap is shorter, skipping is more likely for any given wear state.
The skipping arises from the chain failing to feed cleanly onto the sprocket, under tension. If you load the chain up and wheel the bike forwards you will see the chain not engage properly at the bottom, and once this link gets to the top of the sprocket, the whole chain moves into proper engagement at once, hence it is a 'skip' not a 'slip' perhaps.
If you have the patience you can use the affected sprockets under lighter loads until either they wear into a better shape or the chain wears a little. But you may need the patience of a saint, as well as keeping your wits about you of course; it can be dangerous to have a skip at the wrong time.
Using multiple chains (up to about 0.5%) does wear the sprockets of course, but because the rollers sit in the correct place on the sprockets and share the load better, the sprockets tend to retain their tooth shape better too. It is possible for 0.5 to 1mm of metal to be lost from the loaded faces of sprocket teeth, but the shape can still be good enough to allow a new chain to be used. It is a similar story with chainrings.
