How to use a chain wear tool

[fatblokish]

I have summat a bit like this:


that I use, or rather hope to use, to see how my chain's getting along. However, how do I use it?
Do I insert both prongs into the chain simultaneously (i.e. the shorter distance) or do I insert the RHS prong first and then lower the LHS (i.e. measuring a longer distance according to Mr Pythag).

It seems to me that the tool is not engineered in such a way as to compensate for the hippopotamus as the first method allows the tool, on my present somewhat worn chain, to be inserted on the 0.75mm side but the second does not.

Your guidance please...

 

[Jody]

Slot the left side into the chain and then see if the .75 will drop in between the links. If not the chain has some wear on it. Swap sides and repeat with the 1.00. If that slots in the chain is still ok. However if the 1.00 won't fit then the chain is stretched enough to wear your drive train.

 

[theclaud]

Slot the left side into the chain and then see if the .75 will drop in between the links. If not the chain has some wear on it. Swap sides and repeat with the 1.00. If that slots in the chain is still ok. However if the 1.00 won't fit then the chain is stretched enough to wear your drive train.

Arse-about-face, surely? Neither will drop into a new chain. As it becomes worn the .75 will drop in, and further worn the 1.0 will drop in?

 

[Levo-Lon]

What @theclaud said.

If the .75 is tight the chain is still servicable.. if .1 goes in its worn out

 

[gbb]

Insert the unmarked end (l/h side on the photo) inbetween two rollers and swing the .75 prong into the chain roller.
If the .75 prong wont slide down into the rollers...its less than .75% worn and all is well.
If it slides down into the rollers, its .75 or more worn.
Now turn it over and repeat with the1% indicator. If the 1% indicator drops in between the rollers, your chain is well and truly worn.

My experience is if you replace a chain just before its .75% worn...you can happily get three chains to one cassette. Remember a chain is cheap(ish)... a cassette isnt so much so. Replace a chain early is best IME.
Less wear on drivetrain as a whole.
Less chance of a snapped chain.
Better shifting.

 

[fatblokish]

Thanks for the help folks.

 

[Yellow Saddle]

Insert the unmarked end (l/h side on the photo) inbetween two rollers and swing the .75 prong into the chain roller.
If the .75 prong wont slide down into the rollers...its less than .75% worn and all is well.
If it slides down into the rollers, its .75 or more worn.
Now turn it over and repeat with the1% indicator. If the 1% indicator drops in between the rollers, your chain is well and truly worn.

My experience is if you replace a chain just before its .75% worn...you can happily get three chains to one cassette. Remember a chain is cheap(ish)... a cassette isnt so much so. Replace a chain early is best IME.
Less wear on drivetrain as a whole.
Less chance of a snapped chain.
Better shifting.

A chain does not break because it is worn. The wear of the pins and rollers and bushes has nothing to do with the chain's integrity.
Further, a worn chain does not affect shifting at all. A good chain or a worn chain will shift equally good or bad on the same setup.
In general, these wear indicators are flawed, since they give different readings on clean and dirty chains and, rely on user input, which is very subjective. The best way is still a simple measurement using an inch rule.

 

[bpsmith]

Isn't "an inch rule" a tad too short for measuring a chain?

 

[gbb]

A chain does not break because it is worn. The wear of the pins and rollers and bushes has nothing to do with the chain's integrity.
Further, a worn chain does not affect shifting at all. A good chain or a worn chain will shift equally good or bad on the same setup.
In general, these wear indicators are flawed, since they give different readings on clean and dirty chains and, rely on user input, which is very subjective. The best way is still a simple measurement using an inch rule.

KMCs own view on chain wear is quite clear..shifting can be affected...
http://www.kmcchain.eu/MAINTENANCE

Just musing, for the sake of anyone reading who's interested in their chain).but In essence, taking an interest in your chain is a good thing, rather than just leaving it to someone else once In a while (as in a LBS)
It reduces the likelihood of a failure (something thats only happened once in my lifetime...and that was on an ancient bike many decades ago.)


The use of chainwear indicators are contentious. IIRC the reasoning is they exaggerate actual wear because they give a somewhat false reading because of natural wear in the pin and rollers..but i take the positive from that because that means you're replacing a chain well before excess damage to the rest of the transmission occurs. Some may say thats wastefull...I personally cant get too excited buying say 2 chains a year..thats just running costs.

Chain checkers...no doubt not as accurate, but they do err on the right side...and theyre remarkably quick and easy to use. like everything in life...six and two threes...you pays your money...

 

[gbb]

Isn't "an inch rule" a tad to short for measuring a chain?

Not If you have 12 of them

 

[bpsmith]

Not If you have 12 of them

True, but eleven mates helping you would be tricky.

 

[Yellow Saddle]

KMCs own view on chain wear is quite clear..shifting can be affected...
http://www.kmcchain.eu/MAINTENANCE
That still does not make it true. Nowhere in that claim will you find any explanation as to the mechanism that supposedly causes poor shifting in a worn chain.

 

[Yellow Saddle]

Isn't "an inch rule" a tad to short for measuring a chain?

I hope you weren't pulling my leg implying that we measure the entire chain. If you were, ha ha*, if you weren't, your astute observation is probably the root of most people's frustration using this method. One solution is to use a yardstick and cut off a piece of it but I've found a nice workaround. Partool's spoke ruler is a couple of 1/16th of an inch longer than 12 inches, giving you just enough to play with.

If you tweak the other side, the zero point with a file, you have a near-perfect chain measurement tool, other than the one I've - ahem - patented and am awaiting lucrative licensing deals.

Roller chains and sprockets are widely misunderstood, hence my book on the topic. Cough cough.

* I absolutely refuse to say LOL. I'd rather lick my chain clean than say it.

 

[Wester]

A chain does not break because it is worn. The wear of the pins and rollers and bushes has nothing to do with the chain's integrity.
Further, a worn chain does not affect shifting at all. A good chain or a worn chain will shift equally good or bad on the same setup.
In general, these wear indicators are flawed, since they give different readings on clean and dirty chains and, rely on user input, which is very subjective. The best way is still a simple measurement using an inch rule.

+1
I have often heard from people who seem to know what they are talking about that the best way to measure chain wear is with a steel ruler

 

[Ajax Bay]

the best way to measure chain wear is with a steel ruler

Plus one for this, though for this distance a plastic ruler is fine if one doesn't possess a steel one. I can only assume that some people struggle with the challenge of counting 10 double links, measuring them accurately (in tension, along the line of the chain which you've aberationally put large to large), and then the maths of calculating how much more than 10 inches means a stretch of 0.75% (implying that the chain should be changed without undue delay).