DaveVelo wrote:The purpose of rotating chains is to ensure you don't put a brand new chain on a worn cassette that has wear patterns in the tooth profile (where the 'valley' of the tooth profile is elongated). New chain on worn cassette may bring skipping
Mi scusi ,
I see no difference between having three worn chains and one worn chain. The directive is to replace the old chain "before it wears the gears too much". You're going to get sprocket wear no matter what, but if it's kept at a minimum, you're good to go with two, and if you're a flat lander, maybe even three chains before the cassette is shot.
One last item: If your old chain begins skipping, you may have already passed the threshold. My old chain jumped a couple of times but I was lucky. The new chain is settling in.
Yes you still get the normal sprocket wear - but with chain rotation your chain more closely matches the cassette condition and you don't face the issue of a brand new chain skipping on very worn cassette teeth - by the time the chain is getting to it's most elongation the cassette teeth still match up well. Bottom line is you get to use the equipment deeper into it's capable life.
bm0p700f wrote:Csmpag specify the distance between rollars of 6 links should be 132.2mm. When the chain reaches 132.6mm it shoulod be changed.
Do that and you'll get about half of the useable chain life. What you're really measuring is a mixture of very little actual elongation and mostly roller wear. A bike chain is designed in English units of measure, with a true .500 inch pitch. When new, the space between any two rollers will measure .200-.205 inch. Using Campy's recommendation, you'd trash a chain when it's slightly more than half-worn. If you alternate the use of three chains, you can change the chain when Campy recommends, but don't toss it. After you've used three chains to the recommended "maximum" wear, you can reuse each chain until the wear measurement is about twice what Campy recommends.
Of course, you could also buy another 3 new chains and get the same amount of use from six chains rather than three.
Do that and you'll get about half of the useable chain life. What you're really measuring is a mixture of very little actual elongation and mostly roller wear.
This is true, pivot wear (chain stretch) mostly destroys cogs, not roller wear. I personally do not use Campy chains so cannot comment. However, if you check out a new KMC or YBN chain, you'll notice that the rollers actually float on their pivots.
DaveS wrote:Do that and you'll get about half of the useable chain life. What you're really measuring is a mixture of very little actual elongation and mostly roller wear. A bike chain is designed in English units of measure, with a true .500 inch pitch. When new, the space between any two rollers will measure .200-.205 inch. Using Campy's recommendation, you'd trash a chain when it's slightly more than half-worn. If you alternate the use of three chains, you can change the chain when Campy recommends, but don't toss it. After you've used three chains to the recommended "maximum" wear, you can reuse each chain until the wear measurement is about twice what Campy recommends.
Of course, you could also buy another 3 new chains and get the same amount of use from six chains rather than three.
While the method of rotating chains as you suggest seems to allow one to use 3 chains over a longer period of time, the end result appears to be that you save money in the total number of chains purchased over a specified mileage but at the expense of the certainty of using essentially worn out chains on the chainrings and cassette rendering those components useless once all 3 chains are worn out.
I realize that many posters, including you claim that you are getting upwards of 5,000 miles out of a chain. I would have to say that in my experience, there is no way in hell that I could have a useful service life for a chain of 5,000 miles.
The chain on my girlfriend's bike, on the other hand, still measures inside campy's specs after 4,000 miles. The key difference is that her power at threshold is close to 200 watts and her max sprint is maybe 700 watts, and that's for someone who weighs 130 lbs, so a lot less torque being applied than someone like me who weighs 160 lbs and sprints at a fair bit more than double her wattage. It's not even necessarily the sprints but the continued 1000 plus watt surges that regularly take place as well as lots of time spent above 400 watts that I believe leave my chain worn by 1800 miles.
My experience with my own chains is that once they hit about 1500 (1800 miles max), they are over the .004 elongation figure that I use (about 132.7) which I've adopted from campy's own 132.6 metric with a little added on. I generally measure with calipers, a new campy or CN 7900/6700 chain at approx 132.2 +/- .04 across 10 links. Using campy's 132.6 figure, that works out to about .3% elongation/wear/stretch, whatever you want to call it. I have found that I can push it to .4% and still shift adequately. My experience has shown that, if I forget or get lax about checking chain wear, I start to notice that my shifting becomes more sluggish and imprecise. Measuring at that point confirms my subjective performance observations every time. Take 10 links, and multiply the new figure by 1.004, (about 132.7 over 10 links) and I'm there.
If we assume that you are getting on avg 5,000 miles per chain, using 3 chains, and then have to replace chainrings as well as cassette, then your argument for rotating chains makes better sense than my method of going through approx 6 or so chains/yr. I certainly don't get more than 1.5 yrs useful life out of a set of chainrings/cassette, which would be about the length of time it would take me to log 15,000 miles (a little less time than that actually). In that scenario, you would be 3 chains ahead of me.
But an alternative to your method might be to buy and use 6 chains instead of 3. Theoretically, at the end of the same mileage and end use of 6 chains, you might not have to buy new chainrings or a cassette. DA7900 chainrings and cassette certainly cost more than 3 chains. Cheap FSA rings and 105 cassette, maybe not.
It seems to me that without being able to compare riding styles, conditions, and power outputs, it's difficult to compare apples to apples and dangerous to suggest to others that 5,000 miles or more is acceptable chain life. There are a lot of strong non racing, recreational riders who I could not see safely using a chain more than say, 2,500 miles-of course, that's my opinion.
What I can say that I observe, is that 9/10 people whose bikes I observe or check out, (outside of the more serious racer crowd) are riding around on bikes that shift like yak dung with worn out drivetrains. The degradation has just been so gradual that they no longer remember what a new drivetrain feels like. Funny thing is that they are either squeaking like a bird or grungy beyond belief, not much in between.
I've mentioned this before as another risk of maximizing chain life- someone on a ride just 2 weeks ago went flying over the bars and landed on his chin in a sprint. Cause was a broken chain. SRAM btw.
He lay on the ground for 10 minutes writhing in pain without moving because of the impact on his chin and chest. He's ok, but just something to remember.
I've been reading this thread and just didn't bother posting anything until now, but my experience pretty much relfects yours to a tee. There's no way I will get 5000 miles from a campy chain. And when I notice the shifting is starting to get a little sloppy, the digital calipers I use prettry much reflect Campy's time to replace recommendation of 132.60. Anything beyond that and i'm noticing a degradation in shifting. If I see a 132.65 I'll be replacing it for sure. I've never let it get to 132.70. And my mileage pretty much mirrors yours as well... 1500 miles or so. I'm a bigger guy, at 195-200lbs (88-90kg) so if you're lighter you could probably expect more, but it depends on a lot of factors already mentioned.
Also, I dont' see any point in rotating chains, but then I use campy chains which are not designed to be opened and closed more than once. When I replace a chain, I can tell pretty quickly if the cassette needs replacing as well. And if it does, I'll replace it. I usually get at least two chains per cassette, with my super record cassettes.
I also have quite a few wheelsets, all with mounted cassettes for different purposes. So if you never let your chain get too far out of whack, you're pretty ok with just swapping wheelsets and being assured that the cassettes and chains will mesh ok. Nothing worse than throwing on a wheel with a climbing cassette then heading up the mountains only to find that you've let the chain wear so much on the other wheel that it's skipping over the cassette on this wheel.
It is true that people will ride the same cassette and chain forever and because they wear together everything may seem fine (to them), until they replace one or the other. At that point, both the chain and cassette are toast and need replacing.
It's been about 2 yrs since I've used campy but the couple of times I attempted to use quick links to connect campy chains, I had a few skips while sprinting and the quick links stopped immediately. It's clear many don't experience that but we all ride differently.
I think I might have picked this link up on WW, link pasted at end of post, but it's German mag Tour with quite a few quality tests. One of them is on chain wear, titled "chain gang" in the directory, pg 44 or so. Their spec is essentially .75mm per 10 links as far as what they are calling worn. More than yours and my tolerance for wear. One interesting point they make, which contradicts info some have posted, is that they claim that chain wear do occur in the pin to side plate interface.
They used a mileage of 2800 km, or 1740 miles to arrive at their numbers. (coincident with our experiences) Some of the chains tested had upwards of 3 times their specified wear (SRAM PC 1051, even the new PC 1091R was over double the wear limit at that mileage) whereas a few were just over the minimum, i.e all the shimano 79/67/57 series and campy chains they tested.
This test contrasted to a detailed test conducted by wippermann a couple of yrs ago, only in that the wippermann chain wore the longest in that test whereas here it didn't fare so well. The campy veloce chain was among the top in both tests with the Shimano CN 5701 105 chain the best. Go figure. I thought I was doing well using exclusively ultegra chains at this point for bang/buck, but I might have to rethink that one.
Bla bla bla. Talk to the guys with the facts...........
Lss than 2K km and my chain is gone.
As we say in the Freeride world, "ride it like its stolen!!"
talking to one of the guys with facts........I typically have gotten in the 5K +/- mile range for my Campy 9, 10 , and now 11 speed chains. Lube with Prolink every hundred miles or a smidgen longer. I test my chain by both methods - only using my own versions of the 12" rule and the 132.6 roller measurement that Campy mentions. I toss if the I am getting close to 1/16" elongation in 12" (The common rule of thumb is 1/8") or if I get to 132.4.
Sounds like very harsh conditions and/or poor maintenance.
Quoting the Campy instructions adds nothing to the thread. Their advice to change the chain at 132.6mm or about 5.220 inch was mentioned at the beginning. Do that and you'll use 9 chains to get the same mileage that I can get from 3. At the end of those chain's life, the cassette will most likely be shot, either way. With my method, I intend to trash the cassette after all 3 chains are used up. If you toss chains prematurely, you might get a little more mileage from the cassette, but using 9 chains is far more costly.
Using a Chorus cassette, 3 chains costs about the same as a cassette. Alternating the use of only 3 chains, you save enough to buy the next cassette that you'll need. There's also no reason you couldn't alternate the use of 4 or more chains, if desired. The idea is to get some wear on each chain, so you'll never encounter new-chain skip. That's what usually ends a cassette's life.
Use a cassette with a lot of Ti cogs can result is about half the cassette life as an all steel cassette.
For those of you who do use 3 (or 6) chains, I haven't heard anyone talk about how this wears on the front chain rings. I guess it would work the same, right? The wear on the front rings will match the condition of the chain, right? So, I guess I'm also wondering how the front rings wear compared to cassettes. How often should one change Campy (11s) front chain rings and how MUCH does using 3-6 chains extend wear on front chain rings? Longer than the cassette I'm guessing, since the teeth on the front rings pass through the chain fewer times than the teeth on the smaller cassette cogs. But if that's the case, then what would happen if you used 3-6 chains, then switched to a new cassette and new chains? Would you also have to get new front chain rings? Would the old front rings work with new chains and a new rear cassette?
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