#1
|
|||
|
|||
Chain Stretch
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. |
Ads |
#2
|
|||
|
|||
Chain Stretch
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/ -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#3
|
|||
|
|||
Chain Stretch
In article ,
John B. wrote: .... 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 :-) Chains are half an inch pitch. Put the chain under tension and measure 24 links. At 12 and one eighth inches you're looking at 1% elongation and you're likely to need to replace both the chain and sprockets at the same time. At 12 and one sixteenth inches you're at 0.5% elongation and you're likely to just need to replace the chain. Looks like I need to replace both the sprockets and chain on my hybrid bike :-( If your chainstays are short, you may need to measure just 20 links and work with tenths and twentieths for the elongation. Bear in mind that most riders will mainly use a few sprockets. Those at the extreme end of the cassette get less use. You may find the much used sprockets will not run well with a new chain even if the old chain did not appear to have worn too much. -- Dennis Davis |
#4
|
|||
|
|||
Chain Stretch
cure or find dry seasoned 1x4 or 6 ...poss in thick 1.25 hardwood longer than your chain
mark a new chain's length. measure stretch cleaning, and removing, chain, lubricate n let vertically hang into a container catching drips for 24-36 hours. measure total chain stretch divide into whatever , 2 feet, of average stretch or ...including the new chain measure. |
#6
|
|||
|
|||
Chain Stretch
On 9/15/2017 5:48 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 :-) I vote for "tempest in a tea pot." I understand that measuring pin to pin might give slightly different results than measuring using a chain gauge. But ISTM the difference must be minimal. If (say) your standard for chain replacement is 1/2%, and pin-to-pin gives 0.6% while chain gauge gave just under 0.5%, wouldn't it usually be sensible to replace the chain anyway? BTW, as Andrew said, I think it's worth while to put tension on the chain, not lay it out on a table. If the chain's off, perhaps hanging it from a nail would do. I measure mine on the bike and apply tension by blocking the rear wheel while applying a little force to the cranks. -- - Frank Krygowski |
#7
|
|||
|
|||
Chain Stretch
On 2017-09-15 05:59, Dennis Davis wrote:
In article , John B. wrote: ... 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 :-) Chains are half an inch pitch. Put the chain under tension and measure 24 links. At 12 and one eighth inches you're looking at 1% elongation and you're likely to need to replace both the chain and sprockets at the same time. At 12 and one sixteenth inches you're at 0.5% elongation and you're likely to just need to replace the chain. That's how I monitor it. Why buy a chain gauge when one already has a sufficiently long ruler? After I clean a chain and before lubing it I put a little pull on the chain by leaning my hand on a pedal, then hold the ruler with the 0" mark to a link edge and read the value 12" down the chain. I let my chains to about 0.8% which IME still allows same cassette use. One chain accidentally went to 1% on a long hilly and very dirty MTB ride (with KMC X10.93 it seems the wear accelerates a lot towards the end) and that ruined the cassette. Looks like I need to replace both the sprockets and chain on my hybrid bike :-( If your chainstays are short, you may need to measure just 20 links and work with tenths and twentieths for the elongation. Bear in mind that most riders will mainly use a few sprockets. Those at the extreme end of the cassette get less use. You may find the much used sprockets will not run well with a new chain even if the old chain did not appear to have worn too much. With many the cogs can be turned around which requires dremeling off part of the wider spline for HG cassettes. Fast shifting is gone then but on a road bike that never mattered much to me. -- Regards, Joerg http://www.analogconsultants.com/ |
#8
|
|||
|
|||
Chain Stretch
On Fri, 15 Sep 2017 16:48:59 +0700, John B wrote:
I've been thinking about chain wear, sometimes called chain stretch, and have done a bit of research on the subject. ....snip... 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. Before I check the other answers: I use a chain measuring tool that goes betweenthe rollers. This is on the assumption that what the cog teeth see is the rollers, not the pins. I am assuming that the designers of the tools (I have two, a Park and a Rollhof) took into account that the tools measure two rollers at once, which may double the wear measurement as the two rollers are being pushed in opposite directions. IIRC this was Jobst's complaint about chain checkers. |
#9
|
|||
|
|||
Chain Stretch
On Friday, September 15, 2017 at 8:55:27 AM UTC-6, Frank Krygowski wrote:
On 9/15/2017 5:48 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 :-) I vote for "tempest in a tea pot." I understand that measuring pin to pin might give slightly different results than measuring using a chain gauge. But ISTM the difference must be minimal. If (say) your standard for chain replacement is 1/2%, and pin-to-pin gives 0.6% while chain gauge gave just under 0.5%, wouldn't it usually be sensible to replace the chain anyway? BTW, as Andrew said, I think it's worth while to put tension on the chain, not lay it out on a table. If the chain's off, perhaps hanging it from a nail would do. I measure mine on the bike and apply tension by blocking the rear wheel while applying a little force to the cranks. -- - Frank Krygowski I use a steel rule from Nbar with a spoke oblongness looking a lot lie the new tick puller. the 1x6 is marked at foot or mm intervals whereon chain is laid aside. calling your attention the the unfortunate fact the new chain has 4 ruined links in chain's midsection. reach for the pins you stocked last year n a moderately worn best section of stocked used chain....also found with the board. |
#10
|
|||
|
|||
Chain Stretch
On Friday, September 15, 2017 at 6:25:31 AM UTC-7, duane wrote:
https://www.amazon.ca/s/?ie=UTF8&key...l_9msfsi9pxm_b Are you insinuating that the people that build chains might have a good idea of how to test them? For shame! That's for people like Frank to do. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Chain stretch - actual tech. | James[_8_] | Techniques | 22 | March 7th 13 12:34 PM |
chain stretch question | Mark Cleary[_2_] | Techniques | 16 | November 16th 09 03:32 PM |
Scary chain stretch | Alan Braggins | UK | 1 | December 17th 05 09:45 PM |
Does chain stretch really exist? | Ken Marcet | Techniques | 15 | March 5th 05 09:15 PM |
chain un-stretch? | larry english | Techniques | 2 | August 12th 03 06:41 PM |