I put ~1500 miles on my first chain before learning about chain "stretch"/wear. I ordered a Parktool chain checker and the chain was very worn. I replaced the chain one evening and threw out the old one. When I left for work the next morning, my rear derailleur was binding pretty badly. I was able to find a gear that worked, so I continued riding on that single gear for the next week before I could change out the rear cassette.

I've put roughly 450 miles on the new chain, perhaps 80 of which were on the worn out cassette (I'm not 100% sure on my miles, trying to estimate based on Amazon order dates and Garmin history). Yesterday when I was cleaning my chain, ran the chain checker on a whim and was shocked to find that I was already dropping in on the 0.5 measurement. The 0.7 measure is still good, but I am still shocked that this chain has worn out so quickly.

How long do chains typically last? Could that week of riding it in the single gear on the worn out derailleur have worn it out that much? I suppose if the front cranks and/or the rear derailleur sprockets got worn out from the old chain they could be wearing the chain out at a faster rate.

The chain checkers aren't precise enough to give you week-to-week updates on chain wear. They typically will say that a new chain is worn, even though of course it isn't. Don't worry about it. Check it in a few months.

I have been biking about two years on a bike that I built up, I've ridden probably 6000 miles and have been rotating two chains, they were bought new KMC x9.93. The cassette was bought used off eBay, I don't know how used, but I think not much. I have never checked for chain wear (don't own a checker, but from what I've read a decent steel ruler does the job just as well), and things are running/shifting smooth/quiet enough that I'm not planning on buying new chain(s) any time soon.

PS I lube with Chain-L.

Yes, you can prematurely wear out a new chain with an old cassette.

I generally get about 2,000 miles on a Dura Ace 10 speed chain, and I usually change out the cassette after 8,000 miles....chain wheels usually last about 12,000 to 15,000 miles. This based upon my driving pattern......I average about 4,000 miles a year.

It depends a lot on riding style and conditions. Heavier riders, wet or dusty riding all shorten chain life. Proper lubrication is also essential. A winter commuter might only get 1k miles on a chain, while a fair weather road bike could easily last 5k miles.

I've never had one of those chain checkers say a new chain is worn? (Would kind of defeat the point... right?) Have you personally experienced this?

I replace mine at 3000-4000 miles. That's on the commuter that sees a lot of rain and muck during the winter months. I keep it lubed (once every 2-3 weeks in the winter months.)

Chain checkers? The Shop one KMC sells is digital , the others like Rohloff's is a go/no-go ; an adequate or worn too much test .

Yeah. My winter commuting killed my chain. It was essentially brand-new prior to the snow and salt.

Check out the specs for your chain/groupset. Some say that .5 is acceptable and .7 is when you should replace, others say .7 is acceptable and 1.0 is when you should replace. (I've seen the some chain checkers with .5 and .7 and others with .7 and 1.0)

You may not be as close as you think. But yes, a worn cassette will wear a new chain quite quickly.

Nope - I think you're both just misspeaking... a worn chain will wear out a new cassette - no way a worn cassette will wear out a chain any faster.

I gave up changing chains.

I found I got about 1800 miles on a chain before it read 0.75 on the Park gauge, then I'd replace it. Keeping to that regimen, I found after 9000 miles, the cassette was too worn and I had to replace it with the new chain too.

Then one day I decided to see what would happen if I just didn't replace the damned chain.

I got about 9000 miles out of the combo of the chain and the cassette before it started being a little wonky with shifting.

So IMO the choice is, go through about 5 or 6 chains and one cassette in 9000 miles or go through ONE chain and one cassette in 9000 miles

I suppose eventually the chainring is going to wear too. I've only ridden one about 30,000 miles and never wore one out so I don't know. But I ride pretty inexpensive components and I watch for sales; I did wreck a crank once (stripped the pedal threads) but thanks to watching for sales I had an entire crankset spare that I bought on clearance at Nashbar for $8.

I have 5100 miles on my chain and it's just barely in the range of needing replacing according to the park tool.

You're probably right, I just read it here. But now that I think about it, it seems to be right since chains "wear" by stretching.

I had the opposite experience on my commuter. One month I realized that something felt "off" "gritty" almost in my setup. After thoroughly cleaning and lubing everything, it was STILL there. Lastly, I checked the chain and it was worn according to the park tool. I replaced it and all was well again.

But then again, you have many, many more miles on bikes than I do.

1% is when the chain should be changed. 0.75% is when you should start checking more often.

Best bicycle chain lube

You really use motor oil?

20w60 in the summer. One litre bottle lasts... ages.

Motor oil is just fine. Thicker is good though.

I've started using Chain-L in the summer (on the road bike), Pedro Synlube in the winter to help put up with salt and grime.

Chain-L is, as far as I can tell, just thick motor oil, like maybe 60 weight. Gear lube sort of range.

I've given up on everything that's thin. I tried quite a few thin bike chain specific lubes and none of them worked at all for me, including Boeshield T9

The chain on my gazelle has 2500 miles of daily riding on it since January, I haven't cleaned, oiled, or adjusted it yet, and its still looks like new with no sign of wear.........gotta love enclosed chains.

Would chainsaw chain and bar oil work well on a bike? I'm thinking it would. Right now I've got bike chain oil from the LBS and I'll keep using it until it's gone, but I figure chainsaw bar oil would be a good replacement. Anyone have any experience with that?

Let me google that for you

Less snarky answer: yes, many people have had good success.

Chain saw bar oil is an excellent lubricant for bicycle chains. Mix some with some Mineral Spirits, to make it flow better, and makes it a little easier to wipe down after lubing..... Oil the rollers, to get it to the pins, and try to wipe most of it off of the outside of the chain. 4 parts oil, 1 Mineral Spirits.

I kept running on the same original chain and casette for 4 years with occasional cleaning and lubing. Some times once every 3-6 months, others time more often. My shifting got poor lately so I finally replaced the chain and casette with a brand new set. It did not fix the problem, feels exactly the same (I suspect it has to do with cable housing or cable so I will replace those next). So as far as I'm concerned, you should not change casette or chain until either one breaks or you have extraordinary difficulties with shifting, chain skipping etc. I'm probably going back to my old set now and keeping this new set as spare.

As for rulers and chain wear indicators, I highly doubt that they really work. Chain wear is so microscopical that its practically impossible to measure. There are so many factors involved here that could make measurements seemingly go on either way. Just ride until you can't ride anymore and buy a new set of chain and casette around every 5-7 years.

Chain wear is VERY EASY to measure. The standard way is to hold a ruler up to a chain, and if a "foot" of chain is more than 1/16" longer than a foot, then it's time to change the chain.

Here's the patron saint of greasy hands on the subject:

Chain Maintenance