#21
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Chain Stretch
On Friday, September 15, 2017 at 8:21:14 PM UTC-7, John B. wrote:
On Fri, 15 Sep 2017 07:44:29 -0500, AMuzi wrote: On 9/15/2017 4:48 AM, John B. wrote: I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) Interrupted sideplate chain does indeed wear faster than full roller chain. However both economy of manufacture and side flex (for index shifting) are better with interrupted sideplates. Generally, chain wear is measured with enough tension to take up any slack, not merely laid out on a table. The outer plates are joined by the rivet. The innies float and exhibit wear. By measuring 24 rivets' worth of slop we can effectively get an expanded 'vernier scale' of the very small per-rivet clearance change. Since our functional aspect for chain-to-sprocket efficiency is pitch, a rivet-t-rivet measurement seems right to me and all our gauges here measure that. See section #8d.2 he http://www.faqs.org/faqs/bicycles-faq/part3/ Yup, Brandt (in all his glory :-) I've been using an 18" stainless scale (ruler) which assuming a 1% wear limit is 3/16". (old eyes need big marks :-) I recently came across another chain measuring scheme that seemed to make good sense. Simply pull on the chain at the front of the chain ring forwards to see how much it moves away from the sprocket teeth. That test shows more the wear on the sprockets than that on the chain. |
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#22
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Chain Stretch
On Friday, September 15, 2017 at 4:49:05 AM UTC-5, John B. wrote:
I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) -- Cheers, John B. Since the switch to cassettes (8+ cogs) from freewheels https://www.sheldonbrown.com/free-k7.html , the axle width has remained the same while the cog teeth and chains have become narrower. Since the load and the length are the same, the pressure per square inch has increased to the point where an 11 speed chain basically needs changed with the tire. Single speed chains will basically last until rusty. |
#23
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Chain Stretch
On Saturday, September 16, 2017 at 6:30:48 PM UTC-4, wrote:
Snipped Since the switch to cassettes (8+ cogs) from freewheels https://www.sheldonbrown.com/free-k7.html , the axle width has remained the same while the cog teeth and chains have become narrower. Since the load and the length are the same, the pressure per square inch has increased to the point where an 11 speed chain basically needs changed with the tire. Single speed chains will basically last until rusty. I've resurrected single-speed (coaster brake or 3-speed type)that were rusted nearly solid. Cheers |
#24
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Chain Stretch
On Sunday, September 17, 2017 at 12:30:48 AM UTC+2, wrote:
On Friday, September 15, 2017 at 4:49:05 AM UTC-5, John B. wrote: I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) -- Cheers, John B. Since the switch to cassettes (8+ cogs) from freewheels https://www.sheldonbrown.com/free-k7.html , the axle width has remained the same while the cog teeth and chains have become narrower. Since the load and the length are the same, the pressure per square inch has increased to the point where an 11 speed chain basically needs changed with the tire. Single speed chains will basically last until rusty. I get 3 tires out of a 11 speed chain and if the same criteria is used for replacement for a single speed chain as for a 11 speed than the difference is that much. Lou |
#25
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Chain Stretch
On Sat, 16 Sep 2017 08:00:38 -0500, AMuzi wrote:
On 9/15/2017 10:20 PM, John B. wrote: On Fri, 15 Sep 2017 07:44:29 -0500, AMuzi wrote: On 9/15/2017 4:48 AM, John B. wrote: I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) Interrupted sideplate chain does indeed wear faster than full roller chain. However both economy of manufacture and side flex (for index shifting) are better with interrupted sideplates. Generally, chain wear is measured with enough tension to take up any slack, not merely laid out on a table. The outer plates are joined by the rivet. The innies float and exhibit wear. By measuring 24 rivets' worth of slop we can effectively get an expanded 'vernier scale' of the very small per-rivet clearance change. Since our functional aspect for chain-to-sprocket efficiency is pitch, a rivet-t-rivet measurement seems right to me and all our gauges here measure that. See section #8d.2 he http://www.faqs.org/faqs/bicycles-faq/part3/ Yup, Brandt (in all his glory :-) I've been using an 18" stainless scale (ruler) which assuming a 1% wear limit is 3/16". (old eyes need big marks :-) I recently came across another chain measuring scheme that seemed to make good sense. Simply pull on the chain at the front of the chain ring forwards to see how much it moves away from the sprocket teeth. The ancient rule of thumb for that is replace chain when a 4mm key will slip under the chain. Index shifting will be poor when a 5mm key fits. You cannot stand on the pedals when a 6mm key slides under the links. That's a very rough gradient and not always accurate, but a starting point anyway. Interesting. Thanks. -- Cheers, John B. |
#27
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Chain Stretch
On Sat, 16 Sep 2017 15:30:44 -0700 (PDT),
wrote: On Friday, September 15, 2017 at 4:49:05 AM UTC-5, John B. wrote: I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) -- Cheers, John B. Since the switch to cassettes (8+ cogs) from freewheels https://www.sheldonbrown.com/free-k7.html , the axle width has remained the same while the cog teeth and chains have become narrower. Since the load and the length are the same, the pressure per square inch has increased to the point where an 11 speed chain basically needs changed with the tire. Single speed chains will basically last until rusty. Actually longer. When I was a kid in New Hampshire you put the bike in the cellar for the winter and sometimes in the spring the chain was so rusted that you could hardly move it. The usual cure was to sneak your mother's sewing machine oil, lather the chain with oil, and then ride it. It was surprisingly how quickly the chain "loosened up". -- Cheers, John B. |
#28
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Chain Stretch
On 9/17/2017 1:28 AM, John B. wrote:
On Sat, 16 Sep 2017 13:32:45 -0700 (PDT), wrote: On Friday, September 15, 2017 at 8:21:14 PM UTC-7, John B. wrote: On Fri, 15 Sep 2017 07:44:29 -0500, AMuzi wrote: On 9/15/2017 4:48 AM, John B. wrote: I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) Interrupted sideplate chain does indeed wear faster than full roller chain. However both economy of manufacture and side flex (for index shifting) are better with interrupted sideplates. Generally, chain wear is measured with enough tension to take up any slack, not merely laid out on a table. The outer plates are joined by the rivet. The innies float and exhibit wear. By measuring 24 rivets' worth of slop we can effectively get an expanded 'vernier scale' of the very small per-rivet clearance change. Since our functional aspect for chain-to-sprocket efficiency is pitch, a rivet-t-rivet measurement seems right to me and all our gauges here measure that. See section #8d.2 he http://www.faqs.org/faqs/bicycles-faq/part3/ Yup, Brandt (in all his glory :-) I've been using an 18" stainless scale (ruler) which assuming a 1% wear limit is 3/16". (old eyes need big marks :-) I recently came across another chain measuring scheme that seemed to make good sense. Simply pull on the chain at the front of the chain ring forwards to see how much it moves away from the sprocket teeth. That test shows more the wear on the sprockets than that on the chain. Yes, it may well do that. Or not. I happen to have some extreme "bad example" chainrings with less than 20% tooth height [1] so I measured the root diameter against a new chainring just now. Jobst is correct. The wear is against the loaded side of the tooth, almost no change at root. New 40tt ring root=155mm, utterly worn out=154.8mm [1]replaced on customers' bikes, used here for demo purposes. The one I measured is more worn than this one http://www.yellowjersey.org/photosfromthepast/worn2.jpg -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#29
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Chain Stretch
On 9/17/2017 1:32 AM, John B. wrote:
On Sat, 16 Sep 2017 15:30:44 -0700 (PDT), wrote: On Friday, September 15, 2017 at 4:49:05 AM UTC-5, John B. wrote: I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) -- Cheers, John B. Since the switch to cassettes (8+ cogs) from freewheels https://www.sheldonbrown.com/free-k7.html , the axle width has remained the same while the cog teeth and chains have become narrower. Since the load and the length are the same, the pressure per square inch has increased to the point where an 11 speed chain basically needs changed with the tire. Single speed chains will basically last until rusty. Actually longer. When I was a kid in New Hampshire you put the bike in the cellar for the winter and sometimes in the spring the chain was so rusted that you could hardly move it. The usual cure was to sneak your mother's sewing machine oil, lather the chain with oil, and then ride it. It was surprisingly how quickly the chain "loosened up". Continuing along with "Jobst Appreciation Day" that's because the lubrication which matters is inside the links. Once you broke the plate-to-plate surface rust it moved again. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#30
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Chain Stretch
On Saturday, September 16, 2017 at 10:45:12 PM UTC-7, wrote:
On Sunday, September 17, 2017 at 12:30:48 AM UTC+2, wrote: On Friday, September 15, 2017 at 4:49:05 AM UTC-5, John B. wrote: I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. One method is to lay the chain on a flat surface and measure the wear over, perhaps 12 inches of chain length, from the head of one pin to another. But modern multi speed chains are a bit more complex then the old fashioned chains and the rollers on a modern chain are not supported by the pins but by protrusions on the inner surface of the inner links thus does the distance from roller to roller relate to distance from pin to pin? Another method is to ignore the pin to pin distance and simply measure the roller to roller distance using a chain gauge. But I have also read that when comparing roller to roller measurement to pin to pin measurement there is not necessarily a correlation, or in other words a pin to pin measurement might show one thing while the roller to roller might show a totally different wear pattern. In addition I read that in at least one case the roller to roller wear was not constant and varied from place to place in the length of the chain Brandt, I believe, wrote a treatise on chain measuring gauges and argued that nearly all of them gave an incorrect figure for wear, or perhaps, did it the wrong way. So the question is what is the best system to use to avoid unnecessary sprocket wear, assuming that sprockets cost more and are more trouble to change than chains. There seems to be three options. One, to use a ruler and measure from pin to pin. Two to use a chain tool and measure from roller to roller.. Or three, to use some combination of the two. Or perhaps there is a fourth - ignore the whole thing as a tempest in a tea pot :-) -- Cheers, John B. Since the switch to cassettes (8+ cogs) from freewheels https://www.sheldonbrown.com/free-k7.html , the axle width has remained the same while the cog teeth and chains have become narrower. Since the load and the length are the same, the pressure per square inch has increased to the point where an 11 speed chain basically needs changed with the tire. Single speed chains will basically last until rusty. I get 3 tires out of a 11 speed chain and if the same criteria is used for replacement for a single speed chain as for a 11 speed than the difference is that much. Lou, I understood the first bit well enough but couldn't quite make out the single speed chain wear part. You must either buy cheap tires or ride a hell of a lot more than I do in order to wear out 3 tires per chain. I wear out perhaps a Gatorskin and a half per chain. But I mostly replace chains early since they're relatively cheap and better a chain than wearing out a cassette. |
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