A chain wear checker

[Gatters]

proper chain checkers don't rely on eyesight like a steel rule does

 

[User33236]

Twelve inch steel ruler.

Do you not want a 13" ruler so you can accuarately measure more than 12"?

http://www.tredz.co.uk/.Ice-Toolz-Stainless-Spoke-Ruler_37752.htm

 

[Tim Hall]

Do you not want a 13" ruler so you can accuarately measure more than 12"?

http://www.tredz.co.uk/.Ice-Toolz-Stainless-Spoke-Ruler_37752.htm

Ideally yes. Good find in the link. I keep meaning to scribe lines at 12 1/16 and 12 1/8 inches but never get round to it.

 

[Andy_R]

Do you not want a 13" ruler so you can accuarately measure more than 12"?

http://www.tredz.co.uk/.Ice-Toolz-Stainless-Spoke-Ruler_37752.htm

In a similar vein to @Drago would that be one spoke to rule them all?

 

[Rickshaw Phil]

Or if regicide doesn't appeal then a 12" engineering rule might be better.

We don't need another thread moderated due to a linguistic disagreement.

Edit to add: Since this is the second time this has come up in about a week, if anyone does want to discuss commonly misused words or phrases you could always start a thread in the Cafe.

 

[DRM]

Now there's the thing, it didn't cost me a bean because work supplied it.

 

[dddd]

YahudaMoon correctly points out that only the Shimano checker measures properly, by having two measuring pegs apply force to two rollers in the same direction, while the third ("step #2") peg actually pulls the chain toward the other two pegs!
Is this thing patented? I see no Patent number on mine. Why don't the other cheapie gauges use this approach? You don't want the inconsistent roller freeplay adding to your chain wear measurement and giving a pessimistic reading (unless perhaps you are one who sells new chains).

The Shimano tool seems over-priced. I was given mine for attending one of their seminars. At the limit, it tells you if the chain still has enough life left in it for another service interval of perhaps 500 miles or so.

I've also used a digital caliper's "inside-measure" tips to measure against the centers of the rollers, but had to subtract a 1.2xx" measurement from a 5.2xx" measurement to arrive at a 4.0xx" measurement that was free of any "roller freeplay error". A subtracted net reading of 4.020" thus accurately represents the wear limit equivalent to 1/16" over a 1-foot length.
Advantage to this method is that it tells you your exact degree of actual pitch wear instead of only a "go or no-go" type of indication.
The disadvantage is that the measurement is more tedious and is best repeated at different points along the chain to confirm the precision of one's technique.
I've used this method so many times that I can even detect how poor-quality chains have consistently inconsistent link pitch dimensions from one link to the next!
What a difference between KMC "X"-grade chains and their lesser "Z"-grade chains! I have to take a lot of measurements and average them to evaluate the X-grade chain's degree of wear, it's that uneven.

 

[Gravity Aided]

ProLink ProGold chain wear checker, with percentages engraved.

 

[bpsmith]

Chain tools are only inaccurate if you don't use your head. I can understand the roller play giving an inaccurate reading if you push each end pin as hard as you can when measuring, but who does that?

I have the Park one and I position the pins up to the point where you can obviously feel the added tension from pushing against the rollers. Not difficult to do and has provided consistent measurements compared to a steel rule.

 

[Karlt]

I thought of you when I typed that.

Is this the place to say that I've got 12" but don't use it as a rule?

Sorry. I'll get me coat.

 

[dddd]

Chain tools are only inaccurate if you don't use your head. I can understand the roller play giving an inaccurate reading if you push each end pin as hard as you can when measuring, but who does that?

I have the Park one and I position the pins up to the point where you can obviously feel the added tension from pushing against the rollers. Not difficult to do and has provided consistent measurements compared to a steel rule.

I won't say that you aren't using your head, but you don't understand what was said about the roller free-play causing a doubly pessimistic reading.
If the locating pegs or "hooks" (as they appear) are pushing in opposite directions, as yours and most all other "chain checkers" absolutely do, it doesn't matter if you push or press hard, the free-play under the lightest load has already added a huge amount of nonexistent "stretch" to your tool's reading.

Only by pre-loading the two measured rollers in the same direction can the effect of roller free-play be negated. Either that, or by taking two different-length measurements and subtracting them as I described, negating the free-play measurement from these two different-length measurements.

Making matters worse is that different brands and even models of chain have different amounts of free-play in their rollers, so there is really no way to calibrate one of these simple tools so as to compensate for the gross free-play error.
And as I mentioned, a seller of chains would find no reason to complain as you replace your chain when it is worn to only perhaps 50 or 60% of it's practical wear limit.

The Shimano tool has three pegs for a reason, and why such a simple tool can be sold for such a high price, not that I would necessarily pay it myself.
And likewise why I developed the "subtraction method" on my own, 25 years ago, for the same reason, but which cost me nothing.

 

[bpsmith]

Fair enough @dddd. I see your point and the formula makes sense. My point was that some people push the pins apart as hard as they can to measure chain wear and that clearly isn't an accurate reading.

Going back to your post about averaging the measurements on poorer quality chains, wouldn't it be better to actually take the worst measurement as your wear guide?

If you were assessing a tyre, you wouldn't see a spot on the tyre that you could clearly see the casing through, but average it over the rest of the tyre that you couldn't?

 

[dddd]

Fair enough @dddd. ...Going back to your post about averaging the measurements on poorer quality chains, wouldn't it be better to actually take the worst measurement as your wear guide?

If you were assessing a tyre, you wouldn't see a spot on the tyre that you could clearly see the casing through, but average it over the rest of the tyre that you couldn't?

I don't know how to judge these chains that have such uneven pitch. Even the super-quality chains show much-increased pitch where the connection pin or link is, and I just ignore that.
I would still use the average of the readings, since the biggest measurements don't cause localized problems like slipping or noises. A ruler measurement or a measurement using Shimano's sophisticated 3-peg tool are both taking an average over the length of links that they measure, but if you take measurements that are contacting different rollers, the measurement is seen to fluctuate quite a bit with the Z-series chain as well as with other maker's most inexpensive chains.
I just take a bunch of readings and sort of average the results, but I discard any outlying readings as would similarly result from measuring across the connection pin or link. The difference in readings is not enough to prevent me from identifying a clearly worn-out chain in any case, and I just avoid ever using cheap chain on an expensive cassette.

 

[bpsmith]

Sound reply @dddd. Tbh I can't bring myself to buy ultra cheap chains, precisely as you say. Chainrings and cassettes deserve better. A false economy otherwise.