rpenmanparker is right.

Believe whatever you want, but a worn chain will cause the cassette and chainrings to wear guicker than one that gets replaced regularly.

I'm sure someone has taken the time to document the whole process(maybe Sheldon Brown). If you do a little research, I'm sure you'll find it.

Using an accurate ruler to measure chain wear is far more accurate than any chain wear gauge I've ever seen.

thanks for reminding me of where i, probably, first encountered any convincing info on this stuff. i've ammended a previous post to provide an illustration of what i was trying (apparently without success :() to describe.

I explained how I came to that mileage. Forgot to put "EXCLAIMER: depending on riding conditions and chain cleanliness and lubrication, your mileage may vary." :)

Of course, even if changing chain before 0.5% stretch, that wear should be measured with a ruler (or chain checker, though they often give premature false warnings) - not by mileage.


If chain is changed at .5% stretch, one cassette will not skip with a new chain - it will be good for about 3 chains (if all changed at .5% wear) before needing a new cassette as well.

If chain is not changed at 0.5% stretch, a new chain will definitely skip on the old cassette.

If chain wear exceeds 1% stretch and the chain is still not replaced, it will start wearing front sprockets at a higher rate. Riding this way for long enough will call for new chainrings as well when finally tossing the old chain. Also, there will be a point when a chain and front/rear chainrings get all so worn that it starts skipping with the old chain as well - not just with a new chain. However, riding until this happens can be the cheapest option in the long run, unless front chainrings are some too expensive. That has been my experience at least. If going for absolute budget - just ride the whole drivetrain to the ground, then get a hole new one - preferably a lower-middle class Shimano. My favourite are 8 speed ones with steel front chainrings.

you do realize that your comment in bold here makes no sense at all, a 6-8 sp chain can cost 12-15 dollars canadian--a cassette can cost 20 or 30 or whatever depending on the cassette, and I dont know where you live, but chainrings tend to cost about a dollar a tooth around here, you can find stuff cheaper but it still adds up to much much more than replacing a chain when it gets past 1/16 of an inch over a foot distance.

as you say, you were referring to cheaper stuff, so I guess I can see your point, and frankly, a lot of people never change chains and just ride and ride until the teeth are all shark tooth shaped--so I see your point, but on any decent bike, its cheaper to change out inexpensive chains compared to the other parts, not to mention shifting quality and as I mentioned from a tourers angle, putting yourself in a situation where a possible chain issue could have more serious consequences if you cannot have access to new cassettes.

I would say that your method certainly applies to people riding lower quality bikes and who never take care of their bikes and or care about maintenance, so just dont want to think about it for years and years.

again, perhaps the economics and availability of parts is very different from where you live compared to here when I go in a bike shop and cassettes and chainrings cost X dollars. I guess also the factor of how picky you are is part of it, I have friends who never want to think about changing chains, let alone lubing thier chains....

I know, I explained I ride in rain as well. But to say a chain may need replacing at 2000 miles is kind of bizarre. A chain is barely broken in at that point unless you're putting down 40000 watts up the Alpe in the TDF. 4000 miles, yeah, I start keeping an eye on the stretch but it has much more life past that unless you never clean and lube it.

All I can say is that I've had chains wear past the .5% stretch in under 2000 kilometres (less than 2k miles). Quality ones last up to 4k miles, often less - winter riding especially. Depends on conditions and terrain. Grit is what kills chains fast. Grit and low cadence hard pedalling like up steep hills together - that's as bad as it gets.

Here's my data:

If changed regularly new cassette every 3 chains. New chainring about every 5 cassettes.

Driving chain until it all wears down is about 4 times regular chain replacement mileage.

Let's define average mileage for 0.5 wear as M. It varies from how you clean, lube and where and how you ride. So it is different for each.


So, after 4 x M miles, one has the expenses:

a)Changing chain regularly in that time results in 4 x chain + 1 x cassette cost.

b) Running it all to the ground results in a 1x chain + 1x cassette + 1x crankset cost.




The more expensive crankset you like to use, the more wil the model a) be cheaper.

I guess I can only relate to my experience, I ride about 5000km per year, and ride on two bikes, one 9 speed, the other 8 speed. I pretty regularly get about 5-6000km roughly, out of a chain before it gets to the 1/16 stretch , measured with a ruler. Cassettes are realistically about $40 canadian for 9 speed (in a store here in Montreal, I dont buy the cheapest brands) and on the 8 speed bike, I have recently bought a cheap cassette (IRD) that was about $20 so I will see how it lasts. I tend to buy a middle quality chain, not the cheapest, but for 8 speed its about $20 and maybe $30 for 9 speed.

I guess for me, the factor of nicer feeling shifting with a chain that is not stretched past much the 1/16 inch point is something I feel, and then again, as someone who tours, I dont like the idea of wearing my cassettes and cranksets on a bike that I may use on a trip.

also, I suspect cranksets and chainrings are much more expensive here than what you are referring to.

I guess what it comes down to is that for the amount I ride, changing chains once in a while isnt a big deal, and chainrings and cassettes last me a long time.

I certainly agree that grit on your drivetrain is the main thing to avoid, and regular lubing and drivetrain wiping.

I also change chain regularly, for the same reasons you stated. However, one example is a friend of mine who just uses his bike for commuting. When we put on paper all the costs of his 3x7 drivetrain, we both came to a conclusion that it's cheaper to just run it to the ground once more, like he did the first time when he asked me about what caused skipping and when I concluded that the entire drivetrain is worn because of not changing the chain in time.

i'm beginning to wonder if i were to change my chain often enough, my cassette and chainrings would last indefinitely. :)

that makes complete sense (your friends example)

In our household I overhauled one of our old hybrids used for commuting (6 speed) and the chain was really stretched a lot, got a cheap chain and cheap replacement freewheel and even though the chainrings were probably worn to a certain extent, they were not horrible and the new chain was fine on them--so yes, as in your example, it makes sense just to use stuff until its really worn. Our bike wasnt skipping at the rear (in my experience it has to be really really stretched to do that) but considering how long it had gone with the same chain and freewheel, it was worth changing them both when I changed all the cables, brake pads etc.

I guess the factor is how nice the bike is, and how much you care about it, I wouldnt do this to a nice bike, but many people do....certainly a factor when looking at used bikes.

interesting--this summer I helped someone buy a used bike, and the chain was at about 2/16-3/16 of an inch stretched. I was certain a new chain would skip on the old cassette, but surprising to me it did not when I put a new one on--I guess the originally owner didnt put a lot of power into the pedalling because I have had my old 8 spd bike skip on a new chain with the same stretch more or less, maybe a bit more though.

I definitely makes no difference until the .5% stretch point. You'll get roughly the same mileage from a cassette. Tested i just once though on a MTB 3x8 drivetrain, using rather cheap chains.