I saw where someone replaces their chain every 1200 miles.
Is that a lot?
I'm newish to commuting in all weather (its raining now) and have about 2500 commuting miles in the last year. My bike is 25 years old though and has maybe 3500 miles total on it.
Is my chain ready to go?
Ride it till it breaks?
What do you guys do?

It's about wear/stretch, not breaking;check it for wear w/ good ruler or chain checker

i run 'em till they misbehave. i get many years and thousands of miles out of chains, and clean them regularly. however, i do not ride in the rain much.

I've wrecked chains within a mile of the first rides way back when. One got caught, a cheap new bike. The last time on a friends new one while I was testing/adjusting the bike for him. Back to the LBS...
Mostly I keep chains on almost indefinately as I alt. bikes and don't put on your kind of miles.
Like the man said; they typically don't snap. Shifting suffers prior to anything so very obvious. Seems like you might be due though..

I use Park chain checker (CC-3) to tell me when I need to replace my chain.

Others may know more though.

How long they last is primarly down to several issues... How much you maintain it, how much crap you ride in, and to a lesser extent, the speed of the chain. I know my 10 speed chains get 3k or so miles per chain, the 9 speeds almost twice that. I'm anal about cleaning and lubing.

The Park tool ch9862 listed is cheap and easy, or the ruler method works also.

If your bike is 25 years old, its likely a 7 speed. Those chains are much wider and heavier tahn todays 10 speed ones and last much longer.

I don't change mine when I hit some particular mileage number, but yeah, it's in the neighborhood of 1200. Derailleurs seem to put a little extra tension on a chain, which seems to reduce a worn chain's tendency to misbehave, but my bike has an IGH, so the worn chain tends to fall off a lot, and when that happens I replace it. Also, my bike has small wheels, which puts the chain closer to the ground, which may mean more road dirt; and of course I ride in all kinds of weather, so there's more dirt again. And, finally, being a folding bike the chain is quite short, and that also accelerates chain wear.

i just rolled 2500 miles on my trek 7.5 fx- bought it in april
i decided to changed it out pre-emptively rather than have it break on
my 22 mile ride home from work

My ride is quite dirty, and my chain is usually gunked up pretty badly. In the past I've changed every 1800 miles - though I didn't go by miles, I went by wear. I have a Park chain gauge and change when it hits 1.0 on the gauge.

This last time I was careful to clean the chain more often - it's still impossible to keep clean, but I did clean it occasionally. I got 2000 miles this time before it hit 1.0.

However, I'm getting skip now so I probably SHOULD have changed it at 1.0.

I think what I'm going to do now is to reverse the cogs on my freewheel and run the "good" side from 0 to 1000 miles on the chain, then flip them back and run the worn side on the worn chain until I replace it.

Alternatively, you CAN just run the chain forever. The cog and chain will wear together. I've run 5000 miles on one chain, and maybe you could go even farther. At some point the cogs will get so worn that they'll start skipping anyway. And if you do this, when you're done you WILL have to replace the whole drivetrain.

People who live where they ride on pavement all the time, ESPECIALLY if they avoid riding in the rain, might go many thousands of miles on a chain without trouble.

Chains don't really break from being worn. Each link just gets longer, and that results in the cogs getting worn, so that eventually they start to slip as you pedal.

Here's the master talking about chains:
https://www.sheldonbrown.com/chains.html

and from that page, here's what happens to a sprocket when you run a badly worn chain on it:

A Park chain checker is a good investment. Take your bike to a LBS and have them check it. If your chain is worn
then you'll know. And it's free. If you need a new chain then buy one and learn how to install it. The chain is the most
important part on a bike. It has the most moving parts. That's why it's important to keep it clean. If you commute everyday
then you should be cleaning it at least once or twice a month. Buy a good chain cleaner.

As others pointed out the best way to tell if you need a new chain is to inspect it. There are two issues that come up:

1. Corrosion - For my year round commuter, 6 months of Buffalo Winter riding is brutal. By spring time the chain gets very nasty even with plenty of good lube throughout the winter.
For me a chain on my commuter bike lasts 12 months - it goes on in spring and lasts till the next spring. It is an 8 speed and it gets about 2500 to 3000 miles per year.

2. Wear - This can be measured by special tool or a ruler. As others stated the chain does not actually stretch. The rollers slowly wear over time, when there is enough wear on all of them the chain will be a little longer.
Replace the chain before this is a problem. A chain is cheap. If you let this go you will need New chain, sprocket, and crank... that all can get pretty expensive!

My LBS has a rough rule that works pretty descent: you can expect to get around 1000 miles from a 10 speed chain, about 2000 miles from a 9 speed chain, and about 3000 miles from an 8 speed chain. Where and how you ride will
affect that number greatly, but it is a descent base rule to work from and then use the measure technique to get your exact mileage.

Happy riding,
André

Thank you all for the helpful input. I measured my chain at lunchtime and it is indeed worn.
I still have to ride it home but I'll replace it this weekend.
Once again the Sheldon Brown link was very informative too. Thanks.
I only have 6 gears in back so it is kind of a fat chain.

I want a new bike (whine)

now that you've established you have a worn chain, you might want to decide if you've worn your cassette/freewheel/rear cogs too. If you have, they will chew up a new chain very quickly, so you should replace them at the same time as the chain.

On my route, it's absolutely impossible to keep a chain clean. I posted earlier this month about it. If it's raining, I can mount a brand new chain, ride to work and back once, and the next morning my chain won't even bend. The gravel road I ride on has a clay binder, and it encases the chain like pottery.

Basically, every time I ride in the rain I have to remove the chain, wash it several times in hot water and soap, then dry, soak in mineral spirits, then replace and lube.

I tried a chain cleaner, it's actually easier for me to just take the chain off and put it in a jar with mineral spirits.

Given that the chain is never clean anyway, I've almost given up. If I leave the chain alone and let it get horrible and squeaking before I lube it, I get 1800 miles. If I take it off and clean it once a week, I get 1800 miles. If I use cheap chains ($8) I get 1800 miles. If I use $30 chains, I get about 2000 miles, so that's not worth it at all.

At this point I have probably 12 old chains hanging on the wall of the garage. I'm sort of thinking about starting a rotation; every month, I'll find the least worn of the 12, clean and lube it, and put it on the bike. I could probably keep the bike going with just those 12 chains for a couple of years. Sure, then I'd have to replace the drivetrain, but it's halfway there now and in 10,000 miles I'd have to replace it anyway.

When I was breaking the code about this whole "chain is a consumable, like windshield wiper blades" thing, I became pretty surprised that putting on a new chain could create "new" problems. For me, it was previously unnoticed wear on the middle chainring of my MTB which caused some chunking in the drivetrain with the new chain.

At first it pissed me off that by doing the right thing with my chain I had to spend another $25 on a chainring. But I now note I still have the same cassette, other two chainrings, and jockey wheels with no problems, which I probably wouldn't if I just let it all slide.

I'm nearing 3000 miles on the chain that came with my bike... The last time I had it in the bike shop (a few hundred miles ago) the guy told me it was fine.

I had no idea I should replace my chains so often. At 1200 miles/chain, I'd have to replace a chain every other month! My 10-speed chain is a year old with over 5000 miles. My 8-speed chain is about 2 years old with over 4000 miles. I figured I should replace them about as often as I replace tires, around every 8-10k miles. I haven't had any problems with chain skip, and I do clean and re-lube them pretty often... about once a month in the summer and once per week in the winter. Hmmm, now I wonder if I should replace the chains now or wait until spring.

If your bike is a 6-speed, you should be able to get at least 5,000 miles of use if you buy a good chain and keep it clean and well-lubed. The newer 10- and 11-speed chains wear out much quicker. The chain with my 10-speed group started getting noisy and shifty sloppy at 1,500 miles. I got ride of it for that reason and now have Shimano 9-speed on all of my bikes, and I can easily get 5,000 miles on my 9-speed chains. I change them at 5,000 miles more out principle than need, as they still shift OK and I've never broken a 9-speed chain.

Do you run a 9-speed chain on a 10-speed cassette?

If you're happy w/ performance and w/ your routine then totally no way don't change a thing.

I have found that I cannot do weekly cleanings in the winter, just don't have time, so if that even would help me, well, I don't get to find out. In past years I'd fallen back on just lubing on top of whatever grit is there, just to quell squeaking, and changing out what needs changing as close to summer as I can make it.

This year I'm riding a fixie through as much of this season as I can and it is a dream to my ocd sensibilities. No squeaking, no slipping, no nothing. Ahhhh...

How often you need to change your chain is very dependent on the conditions when you ride. A fair-weather rider who always stays on pavement and lubes the chain regularly can probably get 5000 or more miles from a chain. I'm the complete opposite, I ride all weathers, and my route covers 8 miles round-trip of gravel road which totally coats the chain with very abrasive gunk (even with a wide, long mud flap), so no matter what I do, 2000 miles is about it.

Don't assume you need to change your chain in 2000 miles, just because others do.

Hmmm, I just did Sheldon's chain wear test on both bikes (10-speed chain with 5k miles and 8-speed chain with 4k miles). Both were stretched 1/16" at the 12" mark, which according to Sheldon, means it's time for a new chain. At least the sprockets should still be fine. Kind of a shame to replace the chains just before winter...

If you think the sprockets are fine now, but won't be if you leave the chain on through winter, consider whether you'd rather replace the chain now and give the new one a winter thrashing, or replace the chain and sprockets together after the winter and get a summer or whatever of shiny new performance.