Premature Chain Stretch

[Soltydog]

Best I've ever managed to 0.75mm stretch is a little over a thousand miles, and I'm a big fat jelly arsed lard-O who puts a LOT of stress through the chain. I can't see how a mere mortal could do it in a piffling 300 miles.

I'm a larger rider too & have been known to get less than 1000 miles out of a chain, but 300 miles
I've done 3k miles this year, mainly on 2 bikes, so I'll change the chains on both in the spring even if they have not quite reached .75 wear

 

[Moodyman]

lot of chains stretch quite quickly but once they hit the borderline will stay there for some time.

my chains kmc x8 will often hit the 1/16th inch within 3-400 miles but then stay there for another 1000 miles.
but I check weekly once it hits 1/16 inch

 

[Yellow Saddle]

I took my road bike to my LBS yesterday for a service. They called me to say my chain had about a month left in it. The thing is it's only done 300 miles. They've replaced the chain and I have the original.

1. Is this possible?
2. If it is, how would this happen?

Many thanks.

Chain life is not a function of time but rather a function of distance travelled and chain hygiene. My aunt Edna has a bicycle in her garage that is forty years old and the chain is still perfect. I'm sure you get the point, so drill it into your mechanic's head. It is a nonsense indicator.
A chain has reached the end of its useful life at the point where it exceeds 0.5% elongation over a new one. Your mechanic has to quote the remaining life in percentage elongation if he/she wants to be honest, accurate and unambiguous.
Most chain measurement tools (in fact all of them) are dishonest in that they measure over a short distance and using the rollers as a reference point. The rollers have a variable default position based on how clean the chain in. A short measuring distance accentuates the measuring error. Measure your chain with a 12 inch ruler over 12 inches at the bottom run of the chain. A new chain will line up with the 12 inch mark. When it has reached 12 1/16th of an inch, it has worn (elongated) by 0.5% (96% approximation thereof, which is much more accurate than any commercial chain tool.
I want to emphasize that a chain's useful life is between new and 0.5% elongation, not when it has started to elongate.
Further, once the chain has elongated 1% of its original length, it has destroyed the cassette.
It pays to replace only when necessary and never allow it to go way beyond spec.

 

[Yellow Saddle]

lot of chains stretch quite quickly but once they hit the borderline will stay there for some time.

my chains kmc x8 will often hit the 1/16th inch within 3-400 miles but then stay there for another 1000 miles.
but I check weekly once it hits 1/16 inch

I don't understand how this can happen. The only scenario I can envisage is you ride it in grit for 400 miles and then run it in a filtered oil bath for the next 600 miles. Chain wear is pretty much linear up to the end of its useful life.

 

[Yellow Saddle]

If your cassette is worn, that will cause excessive wear on our chain.

It may do this on a singlespeed without a spring-loaded chain tensioner. On a standard derailer bike a worn cassette will not mesh with a good chain and reject it to the point where the bike is not rideable and therefore it cannot wear the chain.

 

[Nigelnaturist]

furthur to what @marzjennings said up to 12 1/16th is fine between 12 1/16th and 1/8th change the chain, after 1/16th.

@Yellow Saddle I should have read to the end of the thread
I measured mine week before last (not done any distance since) and it showed that little wear i couldn't measure it accurately enough, and its done 2,200 miles, KMC x93 10sp
@slowmotion the only fillings I had as a kid the teeth have gone, the ones that didn't (even two with quite nasty chips) are fine.

 

[Moodyman]

I don't understand how this can happen. The only scenario I can envisage is you ride it in grit for 400 miles and then run it in a filtered oil bath for the next 600 miles. Chain wear is pretty much linear up to the end of its useful life.

I don't know why it happens either. but all I can say is that it has. in fact I had one new chain that was very close to 1/16th inch past 12 inches (I measure chain stretch via the ruler method), but then stayed here until about 1300 miles when it started to stretch further.

 

[Nigelnaturist]

@Moodyman the only thing I can think that might induce early wear is fiinsh of the metals, we are talking quite small items, its a bit like a new cassette and chain whilst new they work, but i find they work better after some miles, simply because they have started to wear of any slight remaining roughness and have become a little matched

 

[Crankarm]

Lordy Lordy ………….. if you can't maintain your bike's transmission then you are at the mercy of an LBS who has an interest in making money. I would suggest the OP buys some bike tools and learns fast. Lordy, Lordy.

I get about 5k miles out of my chains but then I don't grind pushing heavy gears and I keep the chain clean and well lubed. Avoid KMC chains. They are crap at preventing corrosion. Shimano for my bikes, SRAM for my Brompton. All have quick links making removal and refitting a piece of pi$$. I have chain link pliers as well and nitrile gloves. Fail to prepare and prepare to fail.

 

[Yellow Saddle]

Lordy Lordy ………….. if you can't maintain your bike's transmission then you are at the mercy of an LBS who has an interest in making money. I would suggest the OP buys some bike tools and learns fast. Lordy, Lordy.

I get about 5k miles out of my chains but then I don't grind pushing heavy gears and I keep the chain clean and well lubed. Avoid KMC chains. They are crap at preventing corrosion. Shimano for my bikes, SRAM for my Brompton. All have quick links making removal and refitting a piece of pi$$. I have chain link pliers as well and nitrile gloves. Fail to prepare and prepare to fail.

KMC makes Shimano's chains. Different chains have different levels of corrosion resistance but no chain is perfectly corrosion proof, being made of carbon steel. KMC has chains that are plated to prevent corrosion and chains that are not plated. It depends what you want and are prepared to pay for. Shimano also has chains which are not electro-plated. KMC's range is vast and judging the company based on one experience with an inappropriate chain is not fair. It is a very, very innovative and successful company, the largest of its kind, in fact.

 

[Crankarm]

KMC makes Shimano's chains. Different chains have different levels of corrosion resistance but no chain is perfectly corrosion proof, being made of carbon steel. KMC has chains that are plated to prevent corrosion and chains that are not plated. It depends what you want and are prepared to pay for. Shimano also has chains which are not electro-plated. KMC's range is vast and judging the company based on one experience with an inappropriate chain is not fair. It is a very, very innovative and successful company, the largest of its kind, in fact.

Do you work for KMC? Do you work in the chain industry or just a bike mechanic in an LBS who thinks he knows it all?

Are you sure KMC make Shimano's chains? Shimano's chains are made in Malaysia.

Thanks for your patronising wrong assumptions about my inappropriate selection of KMC chain for my bike and my poor bike maintenance. Next time I shall indeed seek your advice and recommendation to get a KMC chain and when it prematurely corrodes sue you for giving me duff advice. FYI I keep my bikes' chains clean and lubed. I bought a supposedly high spec KMC chain which only after one month showed signs of corrosion last november. It had not worn or stretched excessively merely succumbed to corrosion. Cleaning it up really showed how poor the plating was. None of the Shimano HG53/93 or SRAM chains for my Brompton I have ever bought have corroded like this KMC chain did. So I would NEVER EVER buy another KMC chain.

 

[zacklaws]

Crankarm, I see no reason for your attack on Yellow Saddle and his posting, in a similar vein, I could say "Do you work for Shimano", or "Do you work for SRAM", or "just a bike mechanic in an LBS who thinks he knows it all?" because that is the impression you give "You think you know it all".

I myself am a great user of KMC chains and have never had one corrode apart for in the depths of winter when their is a lot of salt on the roads and I have been lazy and not washed it off, but on rare occasions, I have also used Shimano and SRAM chains and see no difference in how quick they wear out. Aprox 1200 miles is what I get out of a chain regardless of make, and I maintain them well, but I also live in a very hilly area along with lots of "Farmers Debris" left on the roads to clog everything up and wear things out quick.

Did your "one off" experience coincide with salt on the roads and not washing it off at the end of the ride? Which is what must have happened as you state "you cleaned it up" to reveal the corrosion, corrosion does not happen straight away, if you maintained your KMC chain like you say you do, clean and lubed, then it would not have corroded.

And where does Yellow Saddle mention anything about your "poor bike maintenance" ? I think you need a trip to specsavers.

Also, not all Shimano and SRAM chains have "Quick Links" as you state in your earlier post. SRAM chains that I have used have a "Powerlock" which is for a "One-time" use only and all the Shimano chains I have used have had a pin which you drive into the chain and then snap off the excess part.........so it seems, what I said earlier " You think you know it all" is correct.....and the reality is.......you seem to know nothing.

And before your next Post......."No, I do not work for KMC or chain industry" or " work in the LBS..............." etc

 

[Nigelnaturist]

@Crankarm I had a KMC chain do 8,000 miles or so, its currently on a hack, but the chain is in great condition, though not sure I will be going anywhere with it. simple I don't ride that bike, just something I aquired and shouldn't have, my current KMC is on 2,000+ with no sign of wear or corrosion, but then like you I do look after them.

 

[andrew_s]

If the shop checked the chain using a checker rather than a ruler, it's perfectly possible that they found it indicating that the chain would shortly need replacing.

Chain checkers are not reliable guides on all chains. It's not unknown for them to indicate that an unused chain is stretched to 0.75% and needs changing.
This is because they measure between rollers, with one roller pushed to the right and one roller pushed to the left. If the chain has more roller movement than the maker of the checker was expecting, the checker shows excessive wear. Roller movement doesn't affect chain performance.
The only checker that checks properly is the expensive shimano checker.

 

[Yellow Saddle]

Do you work for KMC? Do you work in the chain industry or just a bike mechanic in an LBS who thinks he knows it all?

Are you sure KMC make Shimano's chains? Shimano's chains are made in Malaysia.

Thanks for your patronising wrong assumptions about my inappropriate selection of KMC chain for my bike and my poor bike maintenance. Next time I shall indeed seek your advice and recommendation to get a KMC chain and when it prematurely corrodes sue you for giving me duff advice. FYI I keep my bikes' chains clean and lubed. I bought a supposedly high spec KMC chain which only after one month showed signs of corrosion last november. It had not worn or stretched excessively merely succumbed to corrosion. Cleaning it up really showed how poor the plating was. None of the Shimano HG53/93 or SRAM chains for my Brompton I have ever bought have corroded like this KMC chain did. So I would NEVER EVER buy another KMC chain.

http://www.kmcchain.com/en/milestones.php

http://tinyurl.com/lwcsss5