When do you change your chain? Update > It may be too late!

something many mechanics don't use is actually the Park cassette checking tool, a very useful tool but seldom seen?

a worn chain is a worn chain...but as a previous poster mentioned, riders can ride their bikes very differently causing different levels of damage to the drivetrain

a chain that is stretched within tolerance limits (not terminal but requiring replacement) can be replaced with a new chain, yet the new chain on the original cassette will slip as 1-2 sprockets on the original cassette are worn through due to the rider's habits

we see this alot in London bike shops where commuters on road bikes are pushing the same cassette sprockets every day

personally? I will never clean my chain using any solvents, degreaser or chain baths.

The most brutual method would be warm soapy water with an old toothbrush, then rinse with fresh water, dry / wipe and treat with quality dry lube...

...before running the cranks backwards and pulling the chain downwards with hand pressure using an old, clean rag to work excess lube into the rollers and clean off any surface dirt

makes a massive difference to chain durability.

You are right it is too late.

There are two approaches to this problem of chains wearing out.

You can just run everything into the ground and replace chainrings, cassette, chain and jockey wheels when everything starts squeaking at you and you can't shift properly or you can buy a chain wear indicator, check the chain regularly and just replace the chain when it wears out.

At the cheaper end of the market it probably doesn't make too much difference price wise but it's more hassle to get everything changed at once and one big lump to spend rather than buying a new chain every few weeks or months.

At the more expensive end of the market, the cassettes and chainrings are so costly that you will want to make them last as long as possible and so replacing the chain regularly makes economic sense as it prolongs the life of your expensive kit.

Any mechanic, maintenance book or manufacturer will recommend that you clean your chain regularly, check it for wear and change it when it is showing signs of wear. The advantage of this approach is that you take a greater interest in the maintenance and smooth running of your bike and are less likely to suffer a sudden failure when miles from home.

You fallen into the trap of replacing your chain too late and now need a new cassette to make it work with a new chain. You can refit the old chain and run it for longer but you may end up damaging your chainrings too and having to do the lot in one go.

I recommend that you buy a chain wear indicator, they are cheap, and use it every week after you've passed a few hundred miles on your chain. The tool takes the guesswork out of the replacement cycle. If you don't have a decent maintenance guide then it is well worth getting one. Zinn and the Art of Road Bike Maintenance is really good.

The rate of chain wear varies hugely, I don't think you can put a mileage on it. Different people put very different demands on chains - big ring mashers doing turbo work and hard training rides all year are surely likely to cause more wear than someone pootling around on sunny days only. That's before you consider issues like cross-chaining, riding on the same few sprockets or how frequently you clean and lubricate it.

I'd say the 4:2:1 ratio is more like 8:2:1 - a chainring should last longer than 4 chains! But then again, this too may very as a single ring will get more use than the inner on a triple.

Rotating chains with a cassette sounds like complication and you still have to buy 3 chains up front. Fit a chain, clean and lube it regularly then replace it before it's too worn and you'll get at least two, possibly three chains before the cassette requires replacing.

9 speed chains and cassettes are significantly cheaper than 10 speed and you're only giving up one intermediate cog But whether 9 or 10sp Tiagra cassettes are just as good as yer fancy Ultegra with a tiny weight difference. KMC X9 and X10 chains seem to last better than average. Shimano chains are made for them by KMC.

Last time I swapped chains on my MTb I found I also had to tweak the cable tension on the barrel adjuster to avoid the chain jumping about which surprised me. Ymmv

Is that cheaper though? Half decent chain is 30 quid, half decent block about 60. Add the magic links into that (can you even re-use magic links?) and I'm not sure if that's a false economy or not.

To Alan Tullet - have you checked your chain for wear with an indicator? Could be you've become accustomed to slightly dodgy shifts. Changing my chain the other day was like putting clean sheets on the bed. You forget how good it is.

Oh god, that makes it sound like I never change the sheets on my bed. I do. At least every 2000km.

Get three chains with your new cassette and use them in rotation (say every 200-300 miles) instead of waiting for the first chain to stretch by 0.75%.
Your cassette will live longer and you won't need to keep an eye on the chain wear. There will be no issue of replacing the chain too early (waste) or too late (skipping / excessive wear on a cassette).
More economical and idiot proof.

I just changed my chain after almost 3000km - putting my wear indicator on it for the first time it was more than .75% stretched, which is way beyond replacement time.
The new chain had fixed my shifting issues, so it would seem my block is ok for now.

I think you're meant to change every 2000ish km? Block every 4000ish, Chainrings every 8000?

Bear in mind that a worn chain will also wear the teeth on your chainset (though not as quickly as the cassette). I'd strongly recommend a new cassette ASAP, especially if you have some important events to ride. Don't spoil the ship...

10 speed Tiagra is £20 at Wiggle/CRC, 105 is £32.