chain wear indicators?

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I've read a few time, (eg just now https://www.roadbikereview.com/threads/chain-wear-indicator-tools-which-one.238705/ ), that chain wear indicators, the typical type which either does (worn) or doesn't (not worn) drop down into the chain, and that that method of measurement isn't right because it's about the distance from roller centre to roller centre, rather than edge of rollers. Something like that. What on earth's that about? Surely, in use, it's about the mismatch or not between both the teeth on the cassette and separately teeth on the chain ring. And that mismatch involves distance from roller edge to roller edge just as much as from pin centre to pin centre; It's the roller edges which come into contact with the teeth on the cogs so ... ?

Anyway, which chain wear indicator should I get? I've got 10 and 11 speed bikes, don't want to spend a fortune but want something good/reliable (of course).

Thanks.

 

[Ajax Bay]

Last things first: the link length is the same, whatever speed chain it is.
The cheapest and most reliable (if you have arithmetic skills) is a steel ruler (30cm is long enough but I use a 45cm / 18" one) and just measure along the lightly tensioned top section of the chain. At least 10 one inch links.
A new chain measures 254mm (for 10). Measure your used chain and work out the percentage elongation. Above 0.5%: procure a new chain. Nearly 0.75%: replace.
For a 10sp drivetrain it can make economic sense to just use a new cassette and chain until it starts skipping, and then replace both. And repeat.

 

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OK, that's great, thanks.

 

[Deleted member 1258]

I use one of these, when the chain gets to .75 I replace it.

I'm on a 10 speed system, I usually get 3 chains to a cassette and between 2000 and 3000 miles for a chain.

https://www.tredz.co.uk/.BBB-ChainChecker_201070.htm

 

[presta]

The error arises because the gauge is pushing the roller at one end one way and the roller at the other end the other way. For the last word in accuracy you would need the rollers at each end pushed the same way, but as Ajax says, why buy a gauge when a ruler's good enough.

 

[scotsbikester]

There are chain measure tools that don't measure chain wear in the mistaken way presta refers to.

This, for instance:

https://pedros.com/products/chain-checker-plus-ii

Or do the ruler method. Personally I find the Pedro's a bit cleaner and less awkward. But each to their own.

Of course, what true professionals ;-) do is remove the chain, hang it next to a known good reference chain, and compare the difference in length. I did that with my last chain and it was 0.4% longer, even though my Pedro's checker was already reporting 0.5% wear. Damn that gross lack of accuracy (or do I mean precision?)

 

[youngoldbloke]

My Lifeline chain checker indicates .75% wear, my Park Tool indicates not. Which one do I believe and should I replace the chain anyway?

 

[youngoldbloke]

- and it measures 255mm over 10 links, which is nowhere near .75.

 

[scotsbikester]

- and it measures 255mm over 10 links, which is nowhere near .75.

So if my calculations are correct (please tell me if not), that's 1mm of stretch. So 0.393700787401575%. Let's call it 0.4%. I suppose it depends what your definition of "nowhere near" is. But it's over half way to 0.75%. And maybe worth considering how accurate your eyes are, and if you've allowed for parallax and so on.

Like I said, I ditched my last chain at 0.4%, but that was measured over the whole length of the chain, against a new one, so I think more accurate.

I err on the side of caution, I would rather ditch chains a bit early, and save the rest of the drive train.

 

[youngoldbloke]

So if my calculations are correct (please tell me if not), that's 1mm of stretch. So 0.393700787401575%. Let's call it 0.4%. I suppose it depends what your definition "nowhere near" is. But it's over half way to 0.75%. And maybe worth considerso I think I will change it sooning how accurate your eyes are, and if you've allowed for parallax and so on.

Like I said, I ditched my last chain at 0.4%, but that was measured over the whole length of the chain, against a new one, so I think more accurate.

I err on the side of caution, I rather ditch chains a bit early, and save the rest of the drive train.

Yes - It is difficult measuring fractions of a millimetre, and making sure the other end of the rule is at the exact centre of the chain-link pin. I have a new chain in stock so I think I will change it soon. There is a visible discrepancy of almost 0.5mm between the Lifeline and the Park Tool tools when one is placed on top of the other.

 

[wonderloaf]

Steer clear of the Decathlon gauge, I bought one recently together with a couple of SRAM 11 speed chains and according to the gauge the brand new chains were worn beyond the 5% limit.

 

[youngoldbloke]

I will check my gauges against the new chain .....

 

[Lozz360]

The error arises because the gauge is pushing the roller at one end one way and the roller at the other end the other way. For the last word in accuracy you would need the rollers at each end pushed the same way, but as Ajax says, why buy a gauge when a ruler's good enough.

I would have thought that a device that is manufactured and marketed to accurately measure chain wear will have taken into account that the very nature of the gauge would push the rollers in opposite directions.

 

[Lookrider]

Regarding the rule measurements
If you measure in imperial ..it can do away with the calculations and decimals of millimetres

Over 12 inch that's 96 1/8ths of an inch
Meaning an 1/8th is 1% ( almost)
Meanings a 16th is 0.5%
Meaning a 32nd is 0,25%

If your chain measures 12 and 1/32nd = 0.25%
If your chain measures 12 and 1/6th =0,5%
If your chain measures 12 and 3 32nd= 0.75%
If your chain measures 12 and 1/8 th = 1%

Of course as you know its really hard to measure this accurate with common work shop tools ...so its back to the simplicity of a go/no go gauge
I'm still in the learning curve and had the OPs exact concerns about a chain wear indicators and how a main part of maintenance can be over engineered

 

[GuyBoden]

My eyes can't read mm very well using a rule, so I find that the cheap chain gauge/tool is easier, when new the 0.75% won't fit into the chain and then with use when the gauge's 0.75% side fits flat into the chain, replace the chain. Simple.