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i just bought a new drivetrain composing of cassette, rings and chain. will my new drivetrain last twice as long because i bought another chain and am intending to swap them over every 100km or so? bike shop guy liked the theory but had no idea if it will work.

i take it that it is the chain stretching that causes the rings and cassette to wear, so if i use two chains it they will stretch twice as slowly, wearing the others in twice as slowly. yes/no?

just an idea

cheers
 

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I agree with dinoadventures. Cassettes wear because of the metal on metal contact mixed with grime, dirt and moisture, as well as chain elongation. If you put 100 miles on one chain and 100 miles on another chain, you've still got 200 miles on the cassette and chainrings. An interesting thought, but likely not that practical. Chains typically last me a year and a half (year round riding). I think that's pretty good,
 

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mrgavdobaleena said:
i just bought a new drivetrain composing of cassette, rings and chain. will my new drivetrain last twice as long because i bought another chain and am intending to swap them over every 100km or so? bike shop guy liked the theory but had no idea if it will work.

i take it that it is the chain stretching that causes the rings and cassette to wear, so if i use two chains it they will stretch twice as slowly, wearing the others in twice as slowly. yes/no?

just an idea

cheers
I would not use two chains; just replace the chain before it stretches too much. I tried the two chain approach once, and eventually one of the chains skipped on the cassette. However, one was a SRAM and the other Shimano. If you do it, get two identical chains.
 

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About the only thing you'll see....

is a reduction by half in the number of times you'll replace the chain. 90% of drive train wear on the cassette and chain rings is from contact between them and the chain itself. Chain stretch isn't actually chain "stretch". Though it appears that way. Chain stretch is actaully the wearing of the bushing to pin fit of each individual link of the chain. This is also due to metal to metal contact and the addition of dirt, grit etc. The wear allows a certain amount of slop to develop between the pin and bushing, which in turn allows the chain to elongate. None of the components of the chain have actually "stretched", the materials that make up the bushing and pins has actually worn away. This is why cleaning and lubing the chain regularly will increase it's useful life span. It cleans the grit out and lubes the metal to metal interfaces, which in turn reduces wear.

Anyway, bottom line is, 200km on chain rings and cassette is 200km period. Spliting the mileage between 2 chains will likely do nothing for the life of those components. You'll certainly get more mileage before replacing chains of course. But when you divide the total by 2 you'll still only be getting the same amount of life out of them as you would a single well maintained chain. In other words, if you normally get 5000km out of one chain, you'll likely get 10,000km out of 2 chains, whether you use them alternately or not.

Good Dirt
 

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Squash said:
is a reduction by half in the number of times you'll replace the chain. 90% of drive train wear on the cassette and chain rings is from contact between them and the chain itself. Chain stretch isn't actually chain "stretch". Though it appears that way. Chain stretch is actaully the wearing of the bushing to pin fit of each individual link of the chain. This is also due to metal to metal contact and the addition of dirt, grit etc. The wear allows a certain amount of slop to develop between the pin and bushing, which in turn allows the chain to elongate. None of the components of the chain have actually "stretched", the materials that make up the bushing and pins has actually worn away. This is why cleaning and lubing the chain regularly will increase it's useful life span. It cleans the grit out and lubes the metal to metal interfaces, which in turn reduces wear.

Anyway, bottom line is, 200km on chain rings and cassette is 200km period. Spliting the mileage between 2 chains will likely do nothing for the life of those components. You'll certainly get more mileage before replacing chains of course. But when you divide the total by 2 you'll still only be getting the same amount of life out of them as you would a single well maintained chain. In other words, if you normally get 5000km out of one chain, you'll likely get 10,000km out of 2 chains, whether you use them alternately or not.

Good Dirt
Well said.
+1 :thumbsup:
 

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In theory, rotating chains on a cassette should probably increase the life of the cassette and keep in in better overall shape, since it will take longer to be running stretched chains on it.

That's the theory, and if running chains with reusable master links might be worth testing in the real world. The flip side is that I don't think you'll get a meaningful benefit unless you rotated a larger number of chains. Your cassette's wear pattern will match the most worn chain so at the end of the cycle you might not be that much better off than someone who used his 2 chains in sequence, replacing them when the stretch was at or below 1%.

Using the 1% protocol, I typically can go 3 chains in the life of a cassette, (on road) possibly you'd be able to go 4. It could be interesting if you were to try to rotate 4 or 5 chains and see how it played out.

If you are running chains with non-reusable links, the cost of the links or the technical problems of replacing the pins in Shimano chains would eat into whatever gains you'd hope for.

BTW- as the maker of Chain-L, I'd love to hear how you make out if you decide to try this experiment.
 

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I beg to differ with the other responses. I had heard about the theory years ago and tried rotating 3 chains on my prior XC bike, checking the chain length every month or so of riding 3 times a week in muddy, technical Connecticut trails, and never letting one chain wear significantly more than the other chains before rotating to the next. I had over 2 years on the cassette, replaced a number of alloy chainrings but the cassette finally failed due to a rivet on the spider breaking loose. Prior to that, I was replacing cassettes every 6 - 9 months like everyone else. The theory is that the predominant cassette wear factor is the longer link length of the chain as it stretches, wearing into the sides of the teeth because they no longer mesh correctly.

I've got 2 seasons on my Santa Cruz Blur, using 2 chains, again, 3x week as long into the winter as the snow allows and I have not replaced a cassette.
 

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On topic, i think that running thicker (i.e. SS) steel chainrings will make for a longer lasting drivetrain. I think the alu rings wear super fast- soft metal with the power stroke always on the same part of the ring, and that wears the chain and cassette. Still waiting for my current alu SS ring to wear out before i test it though.
 

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RMC99's practical results seem to support the theory, though that's only one report, and it would be nice to have a larger database.

Sprockets wear isn't the result of the same forces as chain wear and a sprocket will wear to match the increrased pitch (stretch) of the chain running on it. In theory, if you were to ride 500 miles replacing the chain every 100 miles, the sprocket's wear "age" would be nearer to one that only had 100 miles on it. After another cycle, at 1000 miles it's "age" would only be 200 miles.

What works against the theory is that when new chains are run on older cassettes, the cassette wear rate is slower than normal until the chain "stretches" to match the cassette's worn tooth profile. So, as a practical matter. you probably would not get the full benefit that the theory promises. However, if you're diligent you should probably see longer lived casssettes as RMC did.

The question isn't whether this works, but more one of degree and cost/benefit figuring the time and efffort involved, and again only if using chains with reusable links.

The thing to remember is that chains wear out cogs, not the other way around, so it's important to replace chains before they are stretched (yes, it's pitch change due to pin wear, but we call it stretched because that's how we measure it) beyond the 1% guideline.
 
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