Stupid chain question

[Dave]

A link is 1/2 inch in length, according to the manufacturers who sell 114 link chains that are 57 inches long. Chain length changes can only be made in 1 inch or 2 link increments and still be joined.

[charliedid]

Originally Posted by Mark McM

But other than with the use of a "half-link" (referenced above), you can't shorten or lengthen a chain by 1 link increments. You have to remove/add 2 links a time - one link with outer plates, and one link with inner plates.

Since the chain engages with only half the teeth on a chainring (or sprocket) at a time, it takes a 4 tooth difference in chainring size to match a 2 link difference in chain length. So you can't really make a chain length adjustment for a 1 or 2 tooth difference in chainring size, and there's only a 50% chance that a chain length adjustment can be made for a 3 tooth difference in chainring size.

Inner and outer plates considered one.

[oldpotatoe]

Originally Posted by charliedid

Inner and outer plates considered one.

Look up 'obtuse' in the dictionary and see a picture of mark...Sunday follies, I guess..

Back to the OP..try it..if it works(various chainstay lengths and der hanger lengths make 'standardization pretty tough), groovy, if it doesn't chain too long, take 'some' link(s) out...

winter chain links..

[SlowPokePete]

Just get a new chain.

SPP

[indy.cyclist]

Originally Posted by oldpotatoe

Look up 'obtuse' in the dictionary and see a picture of mark...Sunday follies, I guess..

I get what Mark is saying. Theoretically he is right and I trust his conclusion of a 50-50 shot.

In practice, yes, there are many variables that we don’t have access to in this discussion.

But I think we have provided the OP with all the tools to make the determination. I am new here. Great discussion.


Sent from my iPhone using Tapatalk

[Mark McM]

Originally Posted by charliedid

Inner and outer plates considered one.

I keep forgetting that the bicycle tech world is often divorced from the rest of the tech world, and that the bicycle world often misuses technical terms that are well defined for the the rest of the technical world.

[charliedid]

Originally Posted by Mark McM

I keep forgetting that the bicycle tech world is often divorced from the rest of the tech world, and that the bicycle world often misuses technical terms that are well defined for the the rest of the technical world.

I'm such a moron.

[dddd]

I often see confusion arising WRT the exact definition of "upshifting" and "downshifting"

Traditionally, downshifting means to a lower (climbing) gear, yet in the realm of derailer bicycles, downshifting is often referred to as shifting to a smaller front or rear sprocket, where the derailer literally moves the upper run of the chain downward to the next sprocket.

And there is the meaning of the word "offset" in the context of bottom brackets/spindles. Offsetting the spindle an actual 1mm makes one end of the spindle appear 2mm longer than the other, but this is often (typically) called "2mm offset" because the right end of the spindle extends 2mm further than the left end. This sometimes also causes confusion when people refer to a needed fixed-cup spacer simulating a spindle with "2mm offset".

But with chains, the # of links printed on the box refers to the sum of the individual inner and outer links including the master link.
At other times or in different industries, "links" might refer to the # of complete (inner plus outer) link pairs.

[Mark McM]

Originally Posted by dddd

But with chains, the # of links printed on the box refers to the sum of the individual inner and outer links including the master link.
At other times or in different industries, "links" might refer to the # of complete (inner plus outer) link pairs.

Exactly. Say I am installing a 12spd Campagnolo drivetrain. The box the chain comes in says "114 links". The Campagnolo 12spd User Manual says for my chainstay length, the chain should be 110 links. So I should remove 4 links. But do I remove a section of chain including 4 pairs of inner plates and 4 pairs of outer plates like Peter suggests, or do I remove a section of chain of chain that has 2 pairs of inner links and 2 pairs of outer links?

Using the same term for two units of measurement only leads to confusion and potential problems.

[oldpotatoe]

Originally Posted by Mark McM

Exactly. Say I am installing a 12spd Campagnolo drivetrain. The box the chain comes in says "114 links". The Campagnolo 12spd User Manual says for my chainstay length, the chain should be 110 links. So I should remove 4 links. But do I remove a section of chain including 4 pairs of inner plates and 4 pairs of outer plates like Peter suggests, or do I remove a section of chain of chain that has 2 pairs of inner links and 2 pairs of outer links?

Using the same term for two units of measurement only leads to confusion and potential problems.

yeegads man...If you hold up a chain, and count..outer plates, new chain..how many do you get?

Or put the chain on small-small, measure, tighten a bit, eyeball it and cut out the appropriate number of chain length, install the pin on the 'virgin' plate..with a proper tool(Campagbnolo, of course)..and go ride....

I just built a 12s rig..used the Campag 'guide', then put the chain on small-small..and viola!! The same 'links' removed'..

[Dave]

I've tried to educate riders who live by the metric system that chains are made to English standards and they should never have to count links. If 110 links are needed, the chain must be 55 inches long, including the 1/2 inch quick link. There should always be a pair of inner links at both ends of the chain, if a quick link is used. If they own no English tape measure, it's 139.7cm.

I have a pin made from a 10D nail in my work bench and a precision rule taped with the center 53 inches away. My new chains are cut to 54.5 inches, without the quick link.

[Mark McM]

Originally Posted by Dave

I've tried to educate riders who live by the metric system that chains are made to English standard ...

Archaically that's true, but not any more. Since the 1930's the British Imperial system of units is no longer an independent measuring system, and its current units are now defined by the metric system. Specifically, an Inch is defined as exactly 25.4 millimeters (0.0254 meters). Current bicycle chains are not their original 1/2" pitch, but are 12.70 mm pitch (which just happens to match the 1/2 inch by the current unit definitions).

When the "1/2 inch" pitch bicycle chain was first used, different countries used slightly different standards for the length of an inch. A US inch was about 25.4000508 mm, whereas the British inch was about 25.399977 mm. In the 1930s, first the British, then the US, redefined their inch as exactly 25.4 mm. And our chains have been exactly 12.70 mm pitch ever since.

There are several other bicycle component size standards that are currently specified with metric units, that just happen to correspond to a British Imperial unit size. For example, common handlebar clamp diameters are 25.4 mm (1 inch) and 31.75 mmm (1 1/4 inch). Front derailleur clamps are commonly available in 28.6 mm (1 1/8 inch), 31.8 mm (1 1/4 inch) and 34.9 mm (1 3/8 inch).

[batman1425]

Originally Posted by Mark McM

Archaically that's true, but not any more. Since the 1930's the British Imperial system of units is no longer an independent measuring system, and its current units are now defined by the metric system. Specifically, an Inch is defined as exactly 25.4 millimeters (0.0254 meters). Current bicycle chains are not their original 1/2" pitch, but are 12.70 mm pitch (which just happens to match the 1/2 inch by the current unit definitions)

If they are a made to a metric standard that "happens to be" an exact unit in imperial standards - are they not interchangeable? Both measurements, 12.70mm and 1/2" are accurate descriptions of the final dimensions, no? To my non-engineer brain, this is a semantic argument over labeling of units depending on what scale is used as the reference.

[Mark McM]

Originally Posted by batman1425

If they are a made to a metric standard that "happens to be" an exact unit in imperial standards - are they not interchangeable? Both measurements, 12.70mm and 1/2" are accurate descriptions of the final dimensions, no? To my non-engineer brain, this is a semantic argument over labeling of units depending on what scale is used as the reference.

I didn't say that in the currently used units they are not interchangeable. This is more of a historical and metrological distinction. For measurement standardization, you always have to trace back to the original reference standard. In this case, the reference standard is the SI meter (or millimeter), not some "English" unit.

You could just as easily make your own chain measuring stick to measure chains, with units marked as "Links" and measuring divisions 12.7mm apart.

[Mark McM]

Originally Posted by batman1425

If they are a made to a metric standard that "happens to be" an exact unit in imperial standards - are they not interchangeable? Both measurements, 12.70mm and 1/2" are accurate descriptions of the final dimensions, no? To my non-engineer brain, this is a semantic argument over labeling of units depending on what scale is used as the reference.

I didn't say that in the currently used units they are not interchangeable. This is more of a historical and metrological distinction. For measurement standardization, you always have to trace back to the original reference standard. In this case, the reference standard is the SI meter (or millimeter), not some "English" unit.

The fact is that today's chains are standardized to a metric size, and it just so happens that the inch is also standardized to a metric size (rather than being its own separate measuring standard). You could just as easily make your own chain measuring stick to measure chains, with units marked as "Links" and measuring divisions 12.7mm apart.

As noted in my earlier post, there are several other component sizes that started with size designations in Inches, but that have since moved to being designated in millimeters. In addition to the handlebars and derailleur clamp sizes, we used also measure tire width inches. What used to 7/8", 1", 1 1/8" and 1 1/4" tires are now 23mm, 25mm, 28mm and 32mm.