Originally Posted by
cyccommute
No, there is no rule of thumb. But 8000 miles is excessive in my experience. That’s more than twice what I normally get and what others claim.
Your comparison to a tire isn’t a good comparison. It comes down to surface area. A tire has lots of surface area to wear off. The pins on a chain have only a very little amount of surface area. The force of pedaling is spread out over the very tiny area while the same force is spread out over two tires with contact patches that are vastly huge by comparison. The rubber also deforms so the wear is spread out even more. Additionally, the rubber is cushioned.
The magic of English is that we can use many words to explain the same thing. Yes, a chain “elongates”. Synonyms for “elongation” are drag out, draw out, extend, lengthen, outstretched, prolong, protract, and, yes, stretch. You could do a whole 10,000 word treatise on chain wear or you could just go with the flow and call it “stretch”. People will probably know what you are talking about.
That would depend. Going much past about 3000 miles on a chain often results in skipping gears on a cassette. Certainly going past about 0.75% “elongation” will usually result in skipping gears. Depends on the bike.
Not a bag article but they tout that a ruler is the “most accurate” way to measure chain wear and even show a picture. You can not have “accuracy” if you are estimating over the range of the instrument. And “estimate” is a guess. You can’t look at the pin being off the end of the scale and say “I estimate that is a 1/16”” and be “accurate” about it. 0.5% wear is 12.065”. 0.25% wear is 12.031” (12 1/32”). 0.8% wear is 12.094” (12 3/32”). I dare anyone to “accurately” estimate 1/32” by sight alone.
All of the above aside, bottom line, chains are cheap. Or, rather, you only need to use cheap chains. Expensive chains don’t wear any less or any more than cheaper versions. If you change a chain and it still has 500 miles left on it, what’s the harm? Better to change the chain often than to have to change the cassette often.
As long as the chain checker shows that the chain is good, then it's good, I've never had a chain break, nor wear out my gears prematurely.
Fine, but technically and scientifically the chain does not stretch, and technical and scientific language is more accurate than humans making up words to say something.
NO, NO, NO. There is no magical mile when things start to happen, it only happens depending on how the chain is abused. On a touring bike a chain is abused the most than on any other type of road biking, and most touring people that I spoke to get 3,000 to 4,000 miles out of a chain, if you're getting a 1,000 miles out of a chain then I suspect that your either cross chaining too much of the bikes chain line is not aligned correctly, or failure to clean and or lube the chain properly, or big guy who likes to grind in slow gears. Heck I've known people to get the same sort of miles I do on a chain so it's not remotely unusual. Here is a forum discussion from chain users:
https://forum.bikeradar.com/discussi...mment_15134068 Even pros in the TDF won't change their chains except for every 2,000 to 3,000 miles whether they need to or not and they get chains for free, so if you're only getting a 1,000 miles out of chain then something is wrong.