A couple of points:
1) My Record 11s chain is currently at 7,343 miles and counting. I've got 8,000 miles on an 8 speed campy chain in the past.
2) I'm no expert but surely chain wear and elongation are not necessarily the same thing? Can't the rollers be totally knackered on their pins, without the chain being any longer?
There are various components of wear on a chain, all of which contribute to elongation or what we might call wear.
Take a look at page 43 here:http://www.campagnolo.com/repository/do ... chains.pdf
" onclick="window.open(this.href);return false;
or take a look at the instructions that come with campy chains.
I've used many different chain wear measuring devices in the past and the most accurate way that I've come across is to use a set of calipers, just as noted in the campy instructions, to measure my chains. Sometimes I am a little lax, such as when I'm just putting in big miles and forget, and without fail, I start to notice when shifting begins to lose it's crispness. The upshifts aren't quite as sharp and I feel like I need to move tighten up the cable pull a 1/4 turn. Every single time I start to feel the shifting become sluggish, I take out the calipers and measure the inside length of ten links just as the instructions indicate. Without fail, the measurement is well outside of the 132.6 that campy outlines. I feel that I push things and usually wait until 132.7 or thereabouts. New campy chains generally fall into the 132.2 or so range when new, DA7900/XTR chains maybe 132.3. I take the length for the 10 links, and multiply by about 1.0045 on the long end and when it exceeds that number, it goes into the bin. That is about .45% elongation. For me, that's 1500-1900 miles on a road bike and about 4 months on my mtn bike, depending on if they were training miles or race miles. Weather conditions and maintenance as well as your average power outputs will affect that greatly. My girlfriend with a threshold power of about 200W still gets only about 3000 miles on a chain before it's sloppy and goes into the bin. Someone riding around easily, perhaps elderly, 13-15 mph avg on the flats, maybe take that out a fair bit more. That's just been my experience.
(none of the below is directed towards you edmundo)
Some will say I'm throwing my money away, but I beg to differ on that.
I'm not saying that you, or anyone else for that matter, is not riding your bikes with thousands of miles on your chains beyond what mfrs recommend. What I'm saying is that you are riding on a chain thats is no longer within original design tolerances, is more prone to breaking under extreme load, and is rapidly wearing out your cogs/chainrings.
Do you ever notice that when you replace a "worn" chain, if you replace them yourself, and you take the old chain and set it flat and extended on a countertop alongside the new chain so that you can simply and easily cut the new chain to length, that you notice that the old chain is half a link or more longer than the new chain with the same number of links? What you are seeing is a stretched out and worn out chain. A chain that no longer rides in the valleys of the cogs or chainrings but rather half way up the tooth, because the distance from pin center to pin center is longer than design tolerances. Put your chain in the big ring and pull forward on the chain at the 3 o'clock position looking from the right side. Do you see the chain links ride forward at 12 and 6 o'clock noticeably? Are you able to create a sizable gap between the chain and chainring at the point you're pulling forward? Now compare it to a new chain on an unworn chainring and see the difference.
Chance are when you put a new chain onto a worn cogset and step on it hard in a sprint or sharp climb, that your chain will skip in the most frequently used cogs.
I could care less how long someone wants to keep a chain on their bike or how long before they change it but if could affect me, I'm not so keen on that.
What bothers me is someone who is not experienced enough to know when their bike has become worn and unsafe, reads people writing on the internet about how they're getting 8,000 miles on a single chain, and then gets in front of me in a race or group ride and steps on it skipping or breaking a chain and crashes 20 people out. I've unfortunately seen that happen a few too many times.
My cleaning consists of simply spraying turtle wax bug and tar remover on to a rag and wiping clean. I do this every 2 or 3 rides, takes 2 minutes, and keeps things clean enough for me.
Chain L and motorex wet lube are what I'm using and they work quite well for me.