Oh, I put it all in the title and ran out of words what to write here.
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4 links per inch times 12 inches per foot times 11 feet gets me 528, but I haven’t counted them. Do you need me to do that? 
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I was hoping my rusted math would somehow add up and I don’t need to count them. 
Measuring 2 old chains and 2 new ones, all have a length of 3345mm (~10.97441ft) resting (pulled with ~ 800g) and 3347mm (~10.98097ft) pulled with 15kg (the theoretical max force of my sled if the frame was not angled and I would cut under the sprocket).
If I assume 528 links my chain pitch would be 6.3352 on the resting chain compared to 6.3390 with 15kg.
If I assume 527 links my chain pitch would be 6.3472 on the resting chain compared to 6.3510 with 15kg.
If I assume 526 links my chain pitch would be 6.3593 on the resting chain compared to 6.3631 with 15kg.
527 links seems closer to the theoretical chain pith of 1/4’’ ~6.35mm.
The other way around 528x6.35=3352.8mm (11ft), my chains should be 7.8mm longer then they are.
527x6.35=3346.45mm (10.9792ft), my chains should be 1.45mm longer then they are.
526x6.35=3340.1mm (10.9583ft), my chains should be 5mm shorter then they are.
I might be totally lost in conversion here and the setup was very urban, so human eyeball error of ~2mm realistic.
All I got out of this day is that the chain stretches 2mm on somewhere around 11ft with 15kg. A force that will not be reached on a single chain with the Maslows we have around.
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I would expect 527 links (since both ends end up with the inner links, not the
outer links it’s an odd number of links)
David Lang
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Sometimes I can’t see the Moose because of all the trees.
Thank you.
I measured out the length of 40 links on a piece of graph paper and then used that to count the links by 40. I came out with 527 links, which measured 131-7/16" (3338.5 mm) laid horizontally with no loading. My chain has been supporting my sled for a month or so, but has only been used for one job, so it’s still pretty new.
Note that chain stretch is fundamentally different than wire, rope, or elastic stretch. The latter are a stretch of the material, while thr former is primarily removing the gaps in the joints. With elastic deformation–sorry, I just switched from “elastic” as a material name to “elastic deformation” as a process in which a material is subjected to a load and “bends but doesn’t break”–the stretch is very repeatable. The stretch in our chains, however, is mostly inelastic, and thus probably not very repeatable.
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