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I was reading the Sept 2016 issue of Bicycling where they were reviewing the SRAM NX series. The blurb for the SRAM chain (below) states that "The PC-1110 chain SRAM recommends for NX ... has performed its duties as well as SRAM's higher -end stuff. And because it hasn't had premium hardening treatments, it actually may be gentler on your cassette and ring than a more expensive chain."

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Any truth to this or is this just advertising-speak that snuck its way into the review? This is Bicycling magazine, after all.

Do hardened chains cause more wear?

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    One could come up with arguments for why hardened chains cause less wear. Because hardened steel is smoother (and less likely to get scratched or develop ridges), it is likelier to remain smooth and cause less friction. – RoboKaren Feb 21 '17 at 23:06
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    The key word is may. Without actual tests I certainly wouldn't argue strongly one way or another. – andy256 Feb 22 '17 at 0:00
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    I'm less concerned about the weasel word "may" than about the veracity of the claim. Of course, "may" be used in all sorts of nefarious words ("... may extend your battery life 300%", "may cure cancer and itching", etc.) but that's beside the point. I just want to know if it's more likely than not that hardened chains cause more wear. – RoboKaren Feb 22 '17 at 1:42
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    A hardened chain will presumably have less "stretch" and that will reduce some forms of cog wear. – Daniel R Hicks Feb 22 '17 at 4:07
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    I think they are blowing smoke to entertain their readers. They provide zero mechanisms why this would be the case. From my understanding chain elongation is the main driver of wear. Hardening should reduce the rate of chain elongation. – Rider_X Feb 22 '17 at 5:22
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There are two sides to this question, for the two places chains contact chainrings and cogs with force: the outer plates and the rollers.

There is probably a grain of truth to the statement in question regarding the hardness of outer plates. Sometimes you do see chainring ramping get worn to the point of not performing as well as a result of the rider, usually a racer, habitually shifting under load. Every once in a while you see it somewhat in advance of the teeth being worn. I don't see why this effect wouldn't be exacerbated the harder the outer links are. (That being said, I'm not sure which if any chains, expensive or not, have outer links that are any harder than other ones, since you don't really gain anything by it, and I'll bet the writer has no data on this either.)

For all the other parts of a chain - pin, roller, and inner link (or the bushing in the case of a traditional 5-piece chain) - you want it as hard as you can get it as long as the other mechanical properties (ductility being the big design counterbalance to hardness here I think) are what they need to be. That's how you get a chain that resists elongation the best and in turn keeps cogs and rings going longer, which is what most cyclists are interested in.

So basically the statement is misleading.

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Hard to say without actual evidence from controlled tests. I interpret the:

...may be gentler on your cassette and ring...

as it being softer metal and hence "gentler" on your parts, but this is sort of a fallacy, as others have pointed out in the comments.

It may be gentler, but will probably cause wear faster due to stretching and the pins not being "as hard" as the hardened chain.

So if you consider this "gentle" claim and weigh it with the fact that your cassette is probably getting "shark teeth" more quickly due to a (marginally) more stretched out chain, then yes, a softer chain could be considered gentler on the parts themselves, but I would expect the drivetrain as a whole to wear faster.

This begs the question; is it actually worth it to buy the more expensive chain?

If the extra wear (or lack thereof) of the cheaper chain causes me to have to buy 2 more chains and an extra cassette per season, than I'd probably go for the better chain. But if using the cheaper chain doesn't really affect my drivetrain consumables scheduled replacement (cassette, rings, chain, pulleys, lube), then I wouldn't be inclined to spring for the more expensive chain. Weight comes into play (i.e. hollow pin) but it is so minimal that I wouldn't really consider it unless I was counting grams. (256g vs 259g for Sram PC1170 vs PC1130 ).

  • I have personally only seen about a 15-25% improvement in longevity with a higher quality chain. Measurable, but not enough to warrant the price difference if longevity was your only concern. (I did notice shifting differences.) – Rider_X Feb 22 '17 at 21:23
  • About the only place I can think it might be "gentler" is on the chainrings or cassette would be the shift ramping under forced shift. In this case the softer chain might help maintain a cassette or chainring shifting performance. – Rider_X Feb 22 '17 at 21:28
  • @Rider_X did you notice better shifting with the cheaper chain? Interesting thought about the cassette ramps. But again there is a trade-off, better ramp condition with worse tooth profiles. – ebrohman Feb 22 '17 at 21:41
  • Within Shimano, I noticed better shifting with more expensive chain, when run on a similar level cassette. Didn't notice much difference on lower level cassettes. The difference isn't much, just how quickly and smoothly a shift will pop into place. – Rider_X Feb 22 '17 at 21:44

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