write it down , report back with your results.. answer your own question ..
they already had a lot of miles on them from international shipping across the pacific, and trucking thru various carriers to get to the store so you could buy it.
do include that as well .

Sounds like you are a secret 1x fan :-)

For chain economics consider 3 chains cost a bit more than a regular cassette (unless you have one of the super expensive XTR 12-speed or SRAm 12 speed etc.). I change my chains when chain elongates to 0.5%.
Take steel ruler and measure 12 links. If they reach 12" and 1/16", replace. Or measure 10 links and replace at 25.5 cm. Both measurements are at about 0.5%.
You will get around 3 chains out of oen cassette and 2-3 cassettes out of one chainring. It depends a bit on if you use all cogs evenly, the 11T wears fastest. YMMV.

For chain maintenance just wipe off the chain after dirty rides or every once a while. Re-lube and wipe off again after the oil soaked in. If you get some dirt on the RD sprocketts, wipe off every once a while. unless it gets muddy, this is all it takes.

How long all gear lasts depends on your force, dirt, water etc. MTB drivetrain parts typically last shorter than road parts due to dirt.

I always buy the cheapest parts, I don't think expensive chains and cassettes last that much longer. Quite the opposite when it comes to expensive light-weight parts with aluminum and titanium instead of steel. any shimano, SRAM or KMC chain will be good. any shimano, SRAM or Sunrace cassette will be good for the price.

Prob'ly not. There are moments, however few and far between, when I do use the other chain rings. If I didn't have them, I would certainly miss them :(

Your suggestion on stretch limit is consistent with [MENTION=2795]Trsnrtr[/MENTION], above, so it makes sense. I haven't been very good about keeping an eye on the chain....and maybe gotten into a poor habit of expecting to have to replace chain *and* cassette at the same time (chain rings seem to last longer) so I've shopped for cheaper cassettes. Sounds like if I monitor the chain stretch more diligently I can invest in a slightly better cassette and have it last a lot longer. Prob'ly should buy/develop some kind of chain stretch indicator so I can check every time I lube the chain (which is fairly often). The side benefit is that the chain ring(s :) should last a lot longer, as well.

Very glad I asked, what might appear to be, a "pedestrian" question. Seem to learn something new all the time. Thx.

Prob'ly not. There are moments, however few and far between, when I do use the other chain rings. If I didn't have them, I would certainly miss them :(

Your suggestion on stretch limit is consistent with [MENTION=2795]Trsnrtr[/MENTION], above, so it makes sense. I haven't been very good about keeping an eye on the chain....and maybe gotten into a poor habit of expecting to have to replace chain *and* cassette at the same time (chain rings seem to last longer) so I've shopped for cheaper cassettes. Sounds like if I monitor the chain stretch more diligently I can invest in a slightly better cassette and have it last a lot longer. Prob'ly should buy/develop some kind of chain stretch indicator so I can check every time I lube the chain (which is fairly often). The side benefit is that the chain ring(s :) should last a lot longer, as well.

Curious question....how sure are we that the chain we buy isn't already mfg'd with something close to .5% stretch to begin with? Are there certain brands people are more sure of than others?

Very glad I asked, what might appear to be, a "pedestrian" question. Seem to learn something new all the time. Thx.

I would stay away from most chain checkers as they don't account for roller wear. For example, the Park tool shows me 0.25% elongation for a brand new chain while my ruler shows me exactly 12" (as Expected). so yes, brand name chains should start out exactly at 12" for 12 links. Shimano and Pedro's make a chain wear tool that correctly takes roller wear into account. the ruler has to be steel, not plastic or other material (same expansion coefficient so the chain and ruler will be the same when cold or hot). So with one of those cheap chaintools you replace the chain too often. That may not be bad, but be aware.

I have 10 and 11 speed drivetrains, so my "cheap" parts are already above bottom of the barrell. I don't know if a chain twice as expensive lasts twice as long, but the cheap chains also last thousands of miles in road use when maintained. A lot of anecdotal evidence,...
You don't have to measure frequently once you kind of know how long they last to 0.5%. Maybe monthly or so.

Seems to me that there might be more than .5% visual error in trying to use a ruler (even a steel one). Movement, visual angle, etc. would affect the reading. How do you do it and still ensure accuracy?

I have a caliper that can give me fairly accurate readings but even that can be problematic (like how to get 2 appropriately relative points to measure....like the same position on the 2 links used for measurement).

Yes, because there is less bending of the chain. I am not sure that it is practical to measure the efficiency difference; it is very small, in the noise compared to different lubrication choices for the chain.

That's why yo measure over 10 or 12 links, minimizes error. with a chain checker you also rely on perfect machining and any error will be applied to just 1 or 2 links.

Get the Pedro's or Shimano checker if convenience is important, or the steel ruler if you can live with measuring. Sure, you may end up replacing at 0.45% or 0.55%, but that is OK. the 0.5% rule is not a hard rule and with regular cassettes and chains the cost shifts a bit forth and back between chain and cassette.

Those other chaincheckers are not accurate by design, so you may as well read tea leaves.

i also stretch the chain when measuring. Put the rearwheel down and push the crank to tension the chain. That way you get real world length under load.

Get a precision 12 machinist rule. Place the end of the rule at the edge of a pin. The pin at the other end will be totally covered when the chain is new. When the covered pin is half exposed, you're just a little over .5%, or 1/16" of elongation. That's easy to see and plenty accurate. I suspect that many people prematurely toss chains, in attempt to avoid new-chain skip. If several chains are used in a rotation, you'll never get new-chain skip and each chain can be used longer.

When Wipperman does a chain wear test, they run them all the way to 1% elongation and the best chains do last far longer than the cheap ones. Only Wipperman's very best chain can beat a Campy chain. In my real-world tests, I've used a full length measuring fixture and never got a Campy chain to reach even .5% elongation before the roller wear and side wear were far too great to continue using the chain. That took 350 hours or 6,000 miles to reach that point. Roller wear is 20-30 times greater than the wear that creates elongation. The original space between the roller is about .205 inch. After 6000 miles, it was about .235 inch. For that reason I use a 6mm wide plug gage to drop between the rollers. If it ever goes through, the chain is really trashed.

I agree that the difference is negligible for real world use, just like any weight savings from smaller chainrings. I just don't understand the popularity of compact cranksets. Do people just prefer lower gearing overall?

(the visual error is reduced by 12 times, since we measure 12 repeating sets of links. Measuring one pair of links would be too hard.)
Chain checkers
Yes, my Park Tool chain checker would show around 0.25% on a new Campagnolo chain. Like the comment above, those chains very slowly elongate, still within 0.5% after 4000 miles, but the rollers and plates get their own wear, making the chain more flexible side-to-side. These tools are quick, and can be good for keeping an eye on a chain's wear.

I think the ruler method is better.

(0.5% is fairly arbitrary. Would 0.04% or 0.07% work equally well?)

Ruler
I use the 1 inch and 13 inch marks on my 18 inch steel ruler. (The edge of this 100 year old ruler is dinged up.)

It's not easy to measure accurately. I grip the chain and ruler together at the 1 inch marker, then view the 13 inch mark. I line up the same edge of the central pin. I do need to have my eye straight on at each end, otherwise the viewing angle is noticeable.

The green line is 0.5%, it's just slightly less than 1/16 inch. ( 0.5% is 12*.005 = .060 inches, 1/16 is .0625)

This measure was at or just past the 1/16 mark (red line). I shifted the chain to big chainring, smallest cog to get the longest return chain line.


https://cimg5.ibsrv.net/gimg/bikefor...ea7eaab79c.jpg


https://cimg7.ibsrv.net/gimg/bikefor...87a8acc635.jpg

My experience, too (with rulers). Similar with a digital caliper. It requires multiple readings to average measurement and isolate errors. Since I use quick-links (to clean and lube chains off the bike), I find it much easier to compare the full length of chains hanging from a nail on the wall. The new chain will be shorter. When the used chain is longer by one full link, it means an elongation of close to 1% -- time to scrap it. (and I rotate 2 chains)

Wow! Great inputs!! Truly appreciate all the sharing. Knew I came here for a good reason :)

What I come away with is that I need to change my chain more often. To do that I need a more accurate AND consistent way to measure the "stretch".

I'll experiment with some of the suggestions here and do some thinking about it from a few different perspectives and see if I can come up with something that can provide me with what I'd like to have (I am an engineer at heart....and by training ;) If I discover anything new that I believe makes sense (and, maybe, even if it doesn't) I will definitely offer it up.

Thx again....and cheers....

Sounds like you've never ridden in the mountains. Smaller rings are not for saving weight, they're for providing the gears you need for the terrain that you ride. Triple cranks used to be the popular way to get more low gears, but triples are just about dead, so now people use a 50/34 with up to a 34T sprocket, instead. I've been riding in Colorado since 2003. There are a lot of really steep hills and long mountain climbs. If I only rode flatter terrain, I wouldn't need the 50/34 crank.

When I was bike shopping in 2005/2006, most road bikes in the local shops were 50/34 and 12/25. Only the "comfort" versions had 25mm tires and a 12/27.
A few riders that struggled with hills got a replacement mountain bike derailleur and a 11/32 cassette.

Now, 50/34 and 11/32 are common, with 25mm or even 28mm tires. That's what I have now, quite an improvement.
And I see some 48/32 cranksets. These would be perfect for a lot of riders.