Do Chain Checkers really measure the stated %0.5, %0.75 etc. ?
12-15-20, 10:50 PM
#126
Senior Member
Here's that process (new chain on the right). There's no doubt about the elongation. FWIW, the old chain was flagged by three different chain checker tools.
Chains hanging from nails on a level line
Worn chain on the left
Three chain-check tools. The Shimano tool (right) is supposedly not influenced by roller wear.
Chains hanging from nails on a level line
Worn chain on the left
Three chain-check tools. The Shimano tool (right) is supposedly not influenced by roller wear.
Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.
12-15-20, 10:56 PM
#127
Senior Member
As far as i can tell from the picture the elongation amounts to 4mm. Assuming its whole chains they are each more than 100 links and at least (100*25,4)/2=1270mm length. Thus, true elongation is only (4/1270)*100=0.3% (!) - Can you verify this?
Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.
Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.
12-16-20, 06:16 AM
#128
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EDIT: Correction, the ruler is marked in tenths on the inches side, so it's at 4/10".
Last edited by Sy Reene; 12-16-20 at 06:22 AM.
12-16-20, 09:33 AM
#129
Senior Member
No its not. Its clearly marked MM on the side im reading and 25.4mm corresponds to 1" as it should. Its 4mm, not 4/10".
12-16-20, 09:35 AM
#130
Senior Member
The least error prone method would be to hang the chains from the same nail, but I believe this is good enough, if, as stated, the nails are level.
12-16-20, 10:17 AM
#131
Senior Member
Thread Starter
You are right, if the final roller was straight when drawing that line (seems a bit rotated in the picture) then this pretty much confirms my readings and suspicion that chain checkers are over measuring the stretch.Of course this is the average stretch maybe a section is stretched and others are not.
12-16-20, 10:21 AM
#132
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12-16-20, 10:42 AM
#133
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Thread Starter
?? Exactly, 25.4mm is at the 1" mark. On the 25.4mm side of the ruler that aligns with the big 1, the lower black drawn line is at the 10mm mark (2 hashes below the 8). On the inch side, the line goes thru the 4th hash mark (out of 10). Ignore where the MM letters are; no idea why it looks that way. It's an odd ruler with tenths of inches, and every 8mm as a marking (instead of cms).
If you look at the original picture 1" mark on the right corresponds to ~25.4 on the MM side(left side).
So MM is the milimeter side and difference is around 4mm!!!
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12-16-20, 10:53 AM
#134
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hmm.. so it's a ruler that measures to 64ths of an inch on one side, and in mms on the other. Ok. The scale is weird though if that's the case. The overall width of the ruler, if you rotate the width down the scale, is then a really skinny approx 11mm wide ruler.
12-16-20, 04:07 PM
#135
Senior Member
As far as i can tell from the picture the elongation amounts to 4mm. Assuming its whole chains they are each more than 100 links and at least (100*25,4)/2=1270mm length. Thus, true elongation is only (4/1270)*100=0.3% (!) - Can you verify this?
Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.
Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.
12-16-20, 06:17 PM
#136
Senior Member
12-16-20, 06:27 PM
#137
Sr Member on Sr bikes
I just want to say that I’m surprised and impressed that we’re on page six of this thread.
Dan
Dan
12-16-20, 08:17 PM
#138
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I have seen way too many drivetrains in need of total replacement because the owner went way too far trying to save a few bucks on a chain. Bottom line is to change before it is worn out and use a good gauge (or ruler) often to determine when to change. Even if you did not get the last 300 miles out of the chain that you might have been able to squeeze, that is better than going too far. An ounce or prevention...
Gauges likely have an inherent error likely when in use (due to misuse or machining variance) so if they are a bit too conservative and overestimate wear that is better than the converse.
Gauges likely have an inherent error likely when in use (due to misuse or machining variance) so if they are a bit too conservative and overestimate wear that is better than the converse.
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12-16-20, 08:52 PM
#139
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As far as i can tell from the picture the elongation amounts to 4mm. Assuming its whole chains they are each more than 100 links and at least (100*25,4)/2=1270mm length. Thus, true elongation is only (4/1270)*100=0.3% (!) - Can you verify this?
Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.
Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.
I'll see if I can get some better documentation. Thanks for all the comments.
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12-17-20, 01:03 AM
#140
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Thread Starter
I probably should repeat the exercise with better attention to details. The chains were hung from nails placed on a level line. The ruler is marked in millimeters. The chain checkers, with the possible exception of the Shimano gauge, definitely exaggerate the amount of wear, predisposing to early replacement of the chain. I will say that I subscribe to the notion that chains are cheaper than gears, so I don't feel too bad about getting slightly less wear out of a chain.
I'll see if I can get some better documentation. Thanks for all the comments.
I'll see if I can get some better documentation. Thanks for all the comments.
As long as the nails are level (when measured with a water level) it should be good.
Your measurements, given it is accurate, clearly shows that these tools are over measuring the wear significantly. %0.5 report is given as early as %0.25-0.3.
Once again the point of this whole thread is whether these tools are measuring what they claim to measure. Otherwise I am still ok with changing the chains early instead of having to change an expensive cassette.
I am curious what was the exact reading on the parktool one that shows percentages?
Please let us know if you remeasure your chains.
Last edited by John_E; 12-22-20 at 12:59 AM.
12-17-20, 08:07 AM
#141
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Six pages and we're discussing how to read a ruler. Was there a snowstorm somewhere?
12-17-20, 09:12 AM
#142
Senior Member
If you want to hang chains from a nail to measure elongation, only use one nail and place the rule very accurately with the center at 53 or 54 inches. 0.5% on a 54 inch chain is 0.27 inch. I use a machinist's rule with 0.01 inch markings.
It's a lot easier to measure horizontally with the nail in a bench top and the rule taped to the bench. I've also used a board with a nail at one end and the rule at the other. You can then hang the measuring board if you want.
It's a lot easier to measure horizontally with the nail in a bench top and the rule taped to the bench. I've also used a board with a nail at one end and the rule at the other. You can then hang the measuring board if you want.
Last edited by DaveSSS; 12-19-20 at 10:42 AM.
