When should I replace my chain?

[Spiderweb]

My bike was fitted with a new chain 4600 miles ago, it still runs perfectly. It is regularly wiped down (never degreased) and lubed the 'mickle way'. I don't have a tool to check for wear but should I be looking at a replacement after so many miles anyway?

 

[Tin Pot]

What would the impact be of chain failure for you...A half hour walk back home, or a days wage lost?

 

[Spiderweb]

What would the impact be of chain failure for you...A half hour walk back home, or a days wage lost?

I'd not thought about chain failure, I've never broken a chain. I just presumed that when a chain was coming to the end of its life it would start sounding rough and the gear change would not be as smooth but at the moment it feels the same as the day it was fitted.

 

[goody]

My old one felt fine up until the moment it snapped. It was on my commuter and I was delaying fiting a new groupset so wouldn't normally run a chain that long (not sure of the mileage) To get me to work the next day I put a newish chain on but the cassette was so worn it slipped as soon as I put any pressure on it. New groupset went on that weekend. You'll get much longer out of cassettes and chainrings if you don't let the chain get too far gone. If you use cheap components it might not matter too much but Dura Ace cassettes are expensive.

 

[boydj]

The problem with running a worn chain is that you get excessive wear on the cogs and chainrings and end up having to replace a lot more than the chain to get things running smoothly once your chain starts skipping - and that's more likely than the chain snapping.

 

[Tim Hall]

My bike was fitted with a new chain 4600 miles ago, it still runs perfectly. It is regularly wiped down (never degreased) and lubed the 'mickle way'. I don't have a tool to check for wear but should I be looking at a replacement after so many miles anyway?

You don't need a fancy chain checking tool. Get a 12 inch ruler (engineer's steel one if you want a bit of authenticity) and measure the distance over 12 links. It should be 12 inches. After 4600 miles I doubt it will be. If it's 12 1/8 change it and you'll probably need to change the cassette too, as the worn chain wears the old cassette to match it. A new chain won't mesh with the worn cassette, with hilarious results. If it's 12 1/16 change it and you should get away without having to get a new cassette.

Edit: I don't think a worn chain is any more likely to fail than a brand new one, as the failure mode doesn't have anything to do with the causes of chain elongation.

 

[gbb]

How much is a chain...£10, £15 ?
Failure to replace in good time will result in a new cassette being required...£20, £30 ?, so then youve doubled, maybe trebled the cost. I had to replace chainrings at about 6000 miles so you're well on the way with them potentially.
Factor in the increasing likelihood of a snapped chain, injury, damage to the bike etc etc...all reasonably unlikely...but that £10 to £15 for a chain begins to look a good price to pay.

Chain life is different for everyone, but 4500 miles is good IMO. Id replace it anyway, I'd be more than happy at that mileage. Its just a running cost you should expect.

 

[Spiderweb]

Thank you for your advice, I need to sort a new chain ASAP.

 

[Ajax Bay]

Pound to a florin you'll find you need a new cassette as well. @goody has intimated this. Measure the chain as per advised and if you've gone over 1% it's very likely that you've worn the cassette beyond further use (with a new chain).
But since the cassette's likely a 'gonner' you may wish to just soldier on till the chain starts skating - perhaps just when you are trying to accelerate turning into a busy road or stepping hard up the crux of a hill.

 

[speccy1]

When it snaps........................

 

[Yellow Saddle]

When it snaps........................

Read Tim's reply and take note.

 

[speccy1]

Read Tim's reply and take note.

I was joking.........some people have no sense of homour

 

[Broadside]

I ran a chain to 7000 miles recently, it was still running 'sweet' however when I put a new chain on the cassette needed replacing and the big front chainring was very worn too. Looking at the maths, it is probably better to replace the chain more frequently and reduce the spend on cassettes etc but there is not a lot in it.

 

[slowmotion]

You can get a handy chain wear tool for about a fiver on ebay. They are really easy to use. I change my chains when they are between 0.50% and 0.75% stretched. Both limits are marked on the tool. It's simple.

 

[Alltalk]

I'd not thought about chain failure, I've never broken a chain. I just presumed that when a chain was coming to the end of its life it would start sounding rough and the gear change would not be as smooth but at the moment it feels the same as the day it was fitted.

How much is a chain...£10, £15 ?
Failure to replace in good time will result in a new cassette being required...£20, £30 ?, so then youve doubled, maybe trebled the cost. I had to replace chainrings at about 6000 miles so you're well on the way with them potentially.
Factor in the increasing likelihood of a snapped chain, injury, damage to the bike etc etc...all reasonably unlikely...but that £10 to £15 for a chain begins to look a good price to pay.

Chain life is different for everyone, but 4500 miles is good IMO. Id replace it anyway, I'd be more than happy at that mileage. Its just a running cost you should expect.

This is all good advice. Probably best to invest in a chain wear tool - they are only a few quid.

The chain is the weakest link in the drivetrain and will be the 1st to go before the cassette of the chainrings.

People are quoting 1000's of miles. That's correct. Maintain your bike and drivetrain. Keep it clean and well lubed.

What makes me laugh is people trying to flog high end cassettes for a lot of money. Once my chain starts going and the cassette is on it's last legs it's bin time!

Makes me laugh the amount of £2nd" aka 5000 mile + cassettes people try selling!!