vane171

Before opening quicklink to remove the chain for cleaning first time, I looked at the chain markings so I would put it back on the same way but found the markup lettering like 'Shimano' would be upright for several links, then it would be upside down for another few, in between would be inserted HG-X and Japan C which also would be up or down... I gave up and disconnected, figuring it will probably be obvious once I examine the chain when clean and stretched on the table under good light.

The only obvious thing is, the lettering should be on the outside (on the other side all plates are blank). But there are two ways you can make a circle from the open chain. One circle will have inside part of the chain engaging into gear teeth and if you open the chain and join it the other way, then what was inside will be outside... and it will make the chain rotate in the opposite direction.

Does it matter at all? Shouldn't chains be rotated like this anyway for even wear? Sort of like car wheels in the old days? Or it doesn't make a difference because what wears out is the pin/bushing, and that's symmetric, I mean round?

I tried to search but all I found were threads on completely different subjects, albeit very interesting, and so I made a new one.

Andrew R Stewart 

Some chains are directional, most are not. Side plates are often not arranged in ant orientation in the factory. Andy

Andrew R Stewart 

I didn't answer the question about changing a chain's orientation on the drivetrain to do something beneficial. I don't see any gain here. The chain will go through equal bends at the front and rear during cross chaining so side flex wear is pretty much equal. One could turn a chain "inside out" in having the top of the chain (on the power run) become the bottom of the chain (on the power run). But real life shows virtually no difference in chain plate/roller wear on the top or bottom side of chains after many miles.

Far more important is the uneven wear of chainrings WRT the rotational alignment. It's very common to see more tooth wear on the rings when the cranks are at their power points then their top/bottom dead centers.

Back in the day before indexed shifting and clocked splined cogs were the standard some freewheels would allow their cogs to be removed and reversed. Resulting is a fresh tooth valley face now bearing on the chain. But real life costs and function pretty much proved this was a very minor benefit. Andy

Crankycrank

As Andrew mentioned, it makes no difference.

Iride01 

To put it in shorter words....

Some chains don't care about their orientation.

Some want a certain side on the outside.

Some might want a certain side out as well as a certain rotation. (I'm just supposing, never had one...... but I've had the others.)

DiabloScott

A lot of modern chains want a specific inside/outside orientation, but this is the only one I know of that wants a directional orientation... and you can see why.

Iride01 

I really do appreciate you showing that. I'd been thinking at one time I saw a chain that had flats on the top and I've been second guessing myself ever since posting.

sweeks

Which side faces the chainrings, cogs and idler pulley? I'm guessing the less-straight side.

Andrew R Stewart 

Correct. But these are generally non directional otherwise. Now a pintel chain might be both. Andy

vane171

To the first part - since the rollers and pins are round, and spin around, they wear out the same way (symmetrically) no matter which way you make the circle with the chain when joining it.

As to the second part, I wonder if the chain gets evenly used all along its length. What I am getting at - is it always the same chain links that get engaged on the same chainring teeth when the cranks are at their power points? Actually thinking as I write this, it might be so only if you rode just one gear, like on a fixie, velodrome bike, but not on bikes with sprocket gears. Riding different gears probably scatters the use of the chain so it is used up evenly on all chain links. That would then affect measuring the chain for stretching. You would need to check a number of measurements to find one that is the longest. Of course, this is really an academic discussion.

jgwilliams

Yup. SRAM use a chain like that on their 12-speed Etap group set.

DaveSSS 

I use the SRAM AXS 12 speed flat top chain on my Campy 12 bike. The flat side obviously has to be up on the top section of chain, but it can be reversed, with either end moving forward.

Andrew R Stewart 

Are the cogs/rings of even tooth counts? If so and if there's no shifting (as in single speed/fixie/IGH) then the chain and teeth will remain clocked to each other. If an odd number of teeth is part of the system then the chain's outer links will move along the teeth of that ring/cog with each turn. This is why wide/narrow rings are always of an even tooth count. Andy

thumpism 

DAZ Studio seems to have lavished attention unevenly on its render model. Check that foot placement versus her garments and, um...accoutrements. "The world on a balcony" is how the French have been known to put it.

https://render-state.net/fw-morgan-hd/

vane171

You must have registered access there... and yep, the first thing I noticed was the shoe (mis)placement on the pedal. Anyway, I like your word choice of expressing the evaluation

Just as I suspected. It would be like the Moon's one side always facing the Earth.

sweeks

Sheldon Brown has an interesting system for extending chain life for SS/FG/IGH drivetrains with even tooth counts: HERE.