chain stretch

mudcow007

bought me a new chain an cassette t'other day as mine seem to be worn out (just over 3000 miles) an is 12months old

i was wondering how much my chain has stretched

using the sheldon method of measure 12 links with a ruler the old chain seems to have stretched about 4 -5 mm

i dunno if this is good or bad

chain is a KMC X9

gtvlusso

mudcow007 wrote:

bought me a new chain an cassette t'other day as mine seem to be worn out (just over 3000 miles) an is 12months old

i was wondering how much my chain has stretched

using the sheldon method of measure 12 links with a ruler the old chain seems to have stretched about 4 -5 mm

i dunno if this is good or bad

chain is a KMC X9

I don't worry too much about chain stretch.

I always go on:

General condition of chain to the keen eye - rusty, broken bits, wear on the rollers?
Is the drive train having difficulty changing gear?
Noisy whilst under load?
Any slippage on the sprockets?

If not, the chain is usually okay.

On the fixie I can get about 8000-10,000 miles from a chain. On the 7 speed (7 speed chains are wider than 9/10 speed chains) I can get over 5000 miles - or about 1 to 1.5 years commuting.

All I do is clean and oil it weekly. Make sure that my cassette/sprocket/chainset is cleaned and not damaged.

mudcow007

aye its slipping like a good un, i've lost the use of the the smallest 3 sprockets!!

dagnammit ive left my chain whip at home grr

trip to halfrauds beckons

itboffin

The most annoying thing about cassette wear is replacement sprockets cost almost as much as an entirely new cassette

bushu

-Thread Revival-
I'm on the 1mm fitting on my chain wear checker tool, I'm guessing this is bad but, no idea how to use this tool tbh hoping my parktools bbb will have the answer :?
Was having drive noise issues anyway, feeling a clicking each rotation of the crank (only under force) was thinking bb as I've not dared remove the crank arms to maintain it since purchase, to prevent me creating issues..

Glad i bought this now, had to make order up to the 20squid free P&P terms (usually done with led's & tubes @ on-one)

Do i change chain or full chainset at this point? would it last until spring?(doesn't seem to be slipping just irritating)
I suppose the answer to that is see how a new chain fits on the chainring, but what would you do?

UndercoverElephant

It depends on if you've just reached the 1 % stretch, or if you've been there for ages. If it's just now, you're in time to just change the chain. If you've left it too long, you may need to change the cassette too.

Chainrings last ages, to be honest, not changed mine in over 10,000 miles - and they still work just fine.

bushu

Not sticking my green colour matched chain on until tart up time, jus booked a clarks ptfe single speed chain in orange for 5 beer tokens at halfrauds.. :? it'll doo for now

cant decide whether i should go now to collect or try remember after work tomorrow, kinda on my way home..
but can imagine the beer meter being low and the friday feeling taking control..

thanks for the inputs

bushu

or do i order the kmc s1 or b1 & wait.. whuts thee bloomin difference here? :?

meanredspider

I hate the term chain stretch - chain wear is far more accurate.

bushu

stretch is the effect of wear but, yeah i'm with ya - had to search both terms to get useful info

still torn between clarks chain & waiting on a kmc s1 to be delivered

meanredspider

bushu wrote:

stretch is the effect of wear

Definition of stretch
verb
[no object]
1(of something soft or elastic) be made or be capable of being made longer or wider without tearing or breaking:
my jumper stretched in the wash
rubber will stretch easily when pulled
[with object] cause (something) to become longer or wider by pulling it:
stretch the elastic
small squares of canvas were stretched over the bamboo frame

I know I'm being pedantic. A chain is neither soft or (in this context) elastic. It just gets longer because the links wear - the plates don't stretch. But, yes, it's pedantic

DrLex

meanredspider wrote:

I know I'm being pedantic. A chain is neither soft or (in this context) elastic. It just gets longer because the links wear - the plates don't stretch. But, yes, it's pedantic

Bugs me too, and I'm not an engineer. When I see it, I think of the expression about objects with unsatisfactory wear being "made of cheese"...

UndercoverElephant

bushu wrote:

or do i order the kmc s1 or b1 & wait.. whuts thee bloomin difference here? :?

Ah, you're a single speeder! In which case I can thoroughly recommend the Cult Crew 510 (it's a rebranded KMC) that I've just fitted to my Day One. Very highly regarded in BMX circles, and seems really free moving.

bushu

so say a chain is 800mm long, it wears in and its now 808mm long.
Has the total length of the chain stretched!? YES!

I must have as much free time as you lot this morning.. but yes chain wear!

EDIT- Thanks UE, will have a looksy

PBo

meanredspider wrote:

bushu wrote:

stretch is the effect of wear

Definition of stretch
verb
[no object]
1(of something soft or elastic) be made or be capable of being made longer or wider without tearing or breaking:
my jumper stretched in the wash
rubber will stretch easily when pulled
[with object] cause (something) to become longer or wider by pulling it:
stretch the elastic
small squares of canvas were stretched over the bamboo frame

I know I'm being pedantic. A chain is neither soft or (in this context) elastic. It just gets longer because the links wear - the plates don't stretch. But, yes, it's pedantic

Except you've quoted the verb. "Chain stretch" is a phenomenon (noun) not a verb. A chain is a collection of linkages. Each link wears, but the overall effect is the entire chain lengthens.

It's kind of like saying "you are NOT ageing, it's just that your cells are losing the capacity to regenerate and repair themselves"

Macro description of a micro phenomenon.

I'll give you chain lengthening over stretch, but not wear. Wear is also too unspecific. Chain side plates could be rubbing against the derailleur mech and wearing thinner. That's chain wear too.

Oh shit, pedantry kicked in before the work day even starts? Some of my colleagues are in for a tedious day today....

bushu

Chain Unit Null Tension measurement tool ooo its friday dunt tha kno

CiB

I was pondering this on my way in.

Is it just me who sees the coincidence that since these chain stretch gauges became widely available everybody seems set on this arbitrary limit beyond which a chain must be changed, and much beyond it is time for new cassette & rings too. That doesn't square with my years of fitting a new chain when the old one starts to look a bit ropey, the horizontal play becomes too much and the once snappy gear changes are becoming a bit hit & miss. It has all the markings of a marketing scam, selling a gauge that is almost guaranteed to show that the chain's worn beyond its limits of use. Every 3 or 4 chains I might swap the cogs as well but tbh I don't tend to keep bikes that long.

And - look at a brand new Shimano chain. The plates resemble small hump back bridges, with a slightly raised centre section. After a while these plates do flatten out - you only have to look at anew one v a 3000 miler to see that. Basic sums for toddlers tells us that if the hump has flattened the pitch has increased. Bingo - chains that stretch, by design. Nice one Shimano.

meanredspider

*excessive pedantry alert*

PBo wrote:

"Chain stretch" is a phenomenon (noun) not a verb.....

Except there is no such noun

Stretch (noun) is a stretch of road.

The phenonenon is chain wear which(amongst other things) leads to the effect of elongation of the chain. It also leads to weakening of the linkages, slop in the rollers and excessive lateral play all of which affect the performance of the chain.

The Rookie

The chain does stretch, every solid with force exerted on it deforms, its just a chain stretches in it's elastic region and springs back, not it's plastic region and stays deformed (except maybe if it's Chris Hoyes!).

Agree, it's not chain stretch, it's elongation due to lots of bits of wear adding up (plates to pins at every joint).

Twostage

I once left a chain too long before changing it. At first I couldnt figure out why when I compared it to the new one it started to go out of sync but by the end of the chain the old and new were back in line. Turns out it had 'stretched' (lengthened) by a full link. Cassette was knackered of course.

desweller

Twostage wrote:

I once left a chain too long before changing it. At first I couldnt figure out why when I compared it to the new one it started to go out of sync but by the end of the chain the old and new were back in line. Turns out it had 'stretched' (lengthened) by a full link. Cassette was knackered of course.

See, at that point you might as well run it until it starts to slip. Nothing really to be gained by changing it.

supersonic

The gauges can be pretty off too. There is merit in the mantra of changing the chain well before you think it is dead as the new chain will bed in easier to the existing profiles ie before it is too late. But if you are using a cheap set up, there is also grounds to run it until it is dead. No real right answer here.

3x9 speed PC951 chains use to be 25 quid, so frequent changing wasn't too hard on the wallet. Many single chainrings can cost the same as a cassette!

gavbarron

The Beginner wrote:

The chain does stretch, every solid with force exerted on it deforms, its just a chain stretches in it's elastic region and springs back, not it's plastic region and stays deformed (except maybe if it's Chris Hoyes!).

Agree, it's not chain stretch, it's elongation due to lots of bits of wear adding up (plates to pins at every joint).

This ^

That is a nice concise explanation. The biggest cause of elongation is the wear in the bushes. As an engineer the term chain stretch really does niggle me. Anyhooooo, back on topic, don't worry about the increase in length of your chain and use it as a determining factor in it's replacement. You'll know when it needs changing as it will skip as mentioned by other posters.

meanredspider

My chain wasn't skipping at all but, even still, the new chain didn't want to play with the old cassette as it was too worn. You really need to decide if you want to save the cassette - if so, you need to change long before you detect any performance issues.

Dezza

Sorry for threadjacking but i'm experiencing a similar problem which is making me wonder if its chainwear.

When i'm riding with the drive train under load it frequently sounds like its out of index (like it wants to change gear). However, when i chuck it on the workstand to tweak the barrel adjuster it sounds ok- so i dont touch it. It's very frustrating.

I was wondering if this is a symptom of chain wear? I'd say the chain has done about 1.5k miles and cassette half that. I'll look into get a chain checker tool if this sounds suspect.

Wrath Rob

bushu wrote:

so say a chain is 800mm long, it wears in and its now 808mm long.
Has the total length of the chain stretched!? YES!

No it hasn't. The distance between the plates remains the same, its the wearing of the rollers/rivets so that they have a smaller diameter that gives the increased length. Sheldon Brown is your friend, as always.

rolf_f

Wrath Rob wrote:

bushu wrote:

so say a chain is 800mm long, it wears in and its now 808mm long.
Has the total length of the chain stretched!? YES!

No it hasn't. The distance between the plates remains the same, its the wearing of the rollers/rivets so that they have a smaller diameter that gives the increased length. Sheldon Brown is your friend, as always.

Ahh, but Sheldon makes the assumption that those referring to chain stretch are always assuming it is the links that are stretching; this may or may not be the case but it doesn't alter the fact that the chain has stretched. The chain is the sum of its components and how they fit together - not any single component. The links can be exactly the same as they were when new but if the complete object known as the chain is longer than it previously was, then it has stretched.

meanredspider

Rolf F wrote:

Ahh, but Sheldon makes the assumption that those referring to chain stretch are always assuming it is the links that are stretching; this may or may not be the case but it doesn't alter the fact that the chain has stretched. The chain is the sum of its components and how they fit together - not any single component. The links can be exactly the same as they were when new but if the complete object known as the chain is longer than it previously was, then it has stretched.

The fallacy of the "stretched" argument is that if you get exactly the same chain and push the ends together it's shorter than the new chain - has it "shrunk" too??? Then, from there, pull the ends until it's the same length as the new chain - Holey Moley - it's all mended - it's neither shrunk nor stretched - that's because, in reality, it's WORN (a state that remains the same no matter how you manipulate the chain)

rolf_f

meanredspider wrote:

Rolf F wrote:

Ahh, but Sheldon makes the assumption that those referring to chain stretch are always assuming it is the links that are stretching; this may or may not be the case but it doesn't alter the fact that the chain has stretched. The chain is the sum of its components and how they fit together - not any single component. The links can be exactly the same as they were when new but if the complete object known as the chain is longer than it previously was, then it has stretched.

The fallacy of the "stretched" argument is that if you get exactly the same chain and push the ends together it's shorter than the new chain - has it "shrunk" too??? Then, from there, pull the ends until it's the same length as the new chain - Holey Moley - it's all mended - it's neither shrunk nor stretched - that's because, in reality, it's WORN (a state that remains the same no matter how you manipulate the chain)

No, because you always use chain in tension and not compression. It is worn but it is stretched as well. No individual component is stretched but the chain as a whole is. Just because a rubber band isn't stretched when it is lying loose on a table doesn't mean it isn't stretched when you stretch it!

meanredspider

Except when it's on the rings it's not really even "stretched" - the pitch remains fixed.

And what happens to the chain when you coast? I bet the friction of the freewheel compresses the chain.

"Stretch" is a sloppy and inaccurate term. What's wrong with "wear"?

But what do I know? I'm only a Fellow of the Institution of Mechanical Engineers so I probably know nothing about tribology

rolf_f

meanredspider wrote:

Except when it's on the rings it's not really even "stretched" - the pitch remains fixed.

And what happens to the chain when you coast? I bet the friction of the freewheel compresses the chain.

"Stretch" is a sloppy and inaccurate term. What's wrong with "wear"?

But what do I know? I'm only a Fellow of the Institution of Mechanical Engineers so I probably know nothing about tribology

But we aren't engineers and terminology doesn't necessarily belong to those fields and may have different meanings outside them. According to the OED - Stretch: Draw, be drawn or admit of being drawn, out into greater length or extension of size - a pretty perfect description of what happens to a chain.

There is nothing wrong with saying the chain is stretched and everything wrong with saying the links are stretched.

As to 'wear' - it's OK but could refer to the side plates being worn (unlikely I know!) - stretch is so much more precise

I sympathise with you on this - I got annoyed with our 'plain English' folk for trying to change 'dewater' into 'abstract' - in the context of a technical document the distinction is significant and abstracting is not exactly the same as dewatering but for the general public abstracting might be better. Deciding when it is appropriate to use the technical term is not necessarily straightforward.