When do you change your chain?

by bikeboy76   March 28, 2013  

Simple question really, but you know the internet, google a simple question and you get so many random answers its hard to tell what is relevant. So I come back to the horse's mouth (as it were, strange idiom.)

I rebuilt my whole drive train about this time last year, and a long learning process it was. This is the first bike, road or mountain, I have had that wasn't knackered once the drive was gone and worth rebuilding. Everything else was just ridden into the ground or sold or stolen (once!) Since then I have ridden more than ever before and covered 5386km/3347miles.

Recently I have hear a little clicking/clacking/cracking rhythmic knocking noise coming from down below, this only happens when I am in a high gear and meet a slight incline; this effectively puts me in too high a gear and putting more pressure on the pedals. If I shift down and spin a bit faster the noise stops.

The rear mech/cranks/cassette replaced Mar 2012 all still feel sharp and new so I suspect the chain. I imagine changing the chain can prelong the life of the other parts. So how far/how often do you change your chain?

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If you buy a chain checking tool, and check your chain frequently, and change your chain when it reaches 0.75% stretched. A worn chain will accelerate wear on both chainrings and your cassette. It is a lot cheaper and easier to change your chain, than letting it wear everything else out!

posted by we8ster [20 posts]
28th March 2013 - 19:08

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In metric measurement, 10 links of a new chain are 25.4 cm, or 15 links, 38.1 cm.

If the rivet is up to 25.5 cm or halfway between 38.2 cm and 38.3 cm, all is well.
If the rivet is a little bit past 25.5 cm, or approaching 38.3 cm, you should replace the chain, but the sprockets are probably undamaged.
If the rivet is approaching 25.7 cm or 38.5 cm, you have left it too long, and the sprockets (at least the favorite ones) will be too badly worn. If you replace a chain at this point, without replacing the sprockets, it may run OK and not skip, but the worn sprockets will cause the new chain to wear much faster than it should, until it catches up with the wear state of the sprockets.
More than that, and a new chain will almost certainly skip on the worn sprockets, especially the smaller ones.

Sir Velo

Raleigh's picture

posted by Raleigh [1734 posts]
28th March 2013 - 19:16

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i change mine every 3 months regardless. like my pants really

posted by russyparkin [578 posts]
28th March 2013 - 22:21

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buy a chain checker - they're cheap and very easy to use.

And then they'll be no need to consult websites where people will tell you about their pants.

TheHatter's picture

posted by TheHatter [811 posts]
28th March 2013 - 23:08


If you change chain, then Change the cassette or you will end up with not smooth shifting. They wear together and should always be replaced together. Chain rings as an when they wear.

posted by guyondebike [34 posts]
29th March 2013 - 0:20

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Chains usually jump on the sprocket if they're particularly worn.

I use a Park CC3 chain checker and replace the chain when it's nearly at 0.75, tested with the chain under tension. Leave it much longer and you'll wear out the cassette prematurely (and eventually the chainrings). Winter use and/or a lack of cleaning & lubing will make it wear out faster. It's a consumable. Replace it.

Is the noise definitely the chain? Or is the sound in time with your pedal strokes?

Simon E's picture

posted by Simon E [2370 posts]
29th March 2013 - 0:21

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Thanks for some great answers, especially Sir Velo, spot on with the specific information, no messing around with the subjective distances. I always say 'A man with a pen never forgets.' I will amend that now to, 'Ctrl+C, Ctrl+V, never forgets.'

My links are 255mm or even 255.5 depending on the accuracy of helix shatterproof plastic ruler markings. This suggests I need a new chain soon. Sorry Guy I will be trying to keep the cassette as it seems in good condition, as a new chain now should hopefully extend the life of my other components; have to balance cost and precaution, as it is still extremely rideable now.

Every three months sounds a bit excessive and expensive (you didn't say how far you ride) but may be an excuse not to clean your chain. I like pants, and lamp.

My Look pedals are a bit wobbly and need replacing, even if they are the source of the sound, the chain advice has been good, thanks.

I am stronger than Mensa, Miller and Mailer, I spat out Plath and Pinter.

bikeboy76's picture

posted by bikeboy76 [1750 posts]
29th March 2013 - 3:42

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I bought a ribble winter bike just over a year ago and didn't show it too much love, It's a training bike, right!. had no problems with it until started getting some nasty pinging noises. Bought myself a chain checker and it turns out the chain should have been binned ages ago. Fitted a new chain and now the gears jump on certain sprockets and I've noticed a few teeth are missing off of the front chain ring, it all needs changing! Spend a few quid now and save yourself a lot of bother and cash, that's my advice.

boffo's picture

posted by boffo [34 posts]
29th March 2013 - 8:23

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Odd that you didn't notice teeth missing from a chain ring. Winter bike, must be very mucky! But the advice here is all correct, and if G has got a 25.5 measurement, don't delay, change it now before any other serious wear means more replacement bits. Mind,after this winter, which is still going on, there will be merit in a good clean down, some checks, and replace what's needed.


posted by doc [167 posts]
29th March 2013 - 10:53

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Mmmm, tough one. Clearly, I'm not as religious about it as some who have commented here, but ... my Trek 2200 is coming up for 9000 miles - and I have never changed either of the front rings since I bought it.

I change the chain when it starts to skip out of gear on the rear cassette and always change the chain and the cassette together. For me, that's about once a year. It still changes perfectly and is a dream to ride, but it isn't ridden every day - just 25-60+ miles 2 or 3 times a week. I always clean the chain down after every ride, wiping it free of dust and dirt and if I've ridden in the rain, I relube it.

Every month, I use a chain washer to give it a thorough clean and thoroughly brush down the cassette and the front rings with the cleaner making sure I get into all the spaces. Works for me!

posted by comm88 [79 posts]
29th March 2013 - 11:10

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comm88 wrote:
Mmmm, tough one. Clearly, I'm not as religious about it as some who have commented here, but ... my Trek 2200 is coming up for 9000 miles - and I have never changed either of the front rings since I bought it.

Chainrings should last much longer than chain or cassette. I recently replaced the chainset on my winter/wet weather/town bike, it must have done well over 12,000 road miles over the last 6 years, nearly all of it on the 42t ring. Have replaced about 6 chains and 4 cassettes in that time.

I wipe my chain down regularly (usually weekly, more in the wet) with WD40 sprayed on a rag. Once dry I relube with Green Oil using an old toothbrush along the inner run of the chain. Most times I also clean between the cassette cogs, as dirt gets caked in there.

Simon E's picture

posted by Simon E [2370 posts]
30th March 2013 - 0:12

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this forum is excellent, I'm learning so much, give me another 6 months of reading on here and I could be a pro mechanic lol.

posted by billyman [142 posts]
20th May 2013 - 8:51


Surely its far more economic to regularly replace chain than do the whole lot in one go - i think my latest cassette has lasted for about 3 or 4 chains now - and the chainrings have outlasted several cassettes. The key is to replace before the chain gets too stretched - its as this point that it will start to wear the teeth of cassette and chainrings and you are stuck in a cycle of replacing the whole lot

posted by rockfield [68 posts]
21st May 2013 - 15:33


I typically use three KMC chains per (basic) cassette in rotation and I change them every 1-2 weeks (200-400 miles)
It's very quick with a "Missing Link".

That way I expose my cassette to less wear than if I waited for individual chains to stretch up to 0.75% before replacement.
The added bonus is that I don't have to measure the wear.

P.S. Other than an occasional wipe I never deep clean or degrease them as it's not economically viable considering the time involved.

I don't follow trends. Trends follow me.

posted by BBB [244 posts]
21st May 2013 - 23:29

1 Like

Do remeber when thinking that there are teeth "missing" on your chain rings rthat it is not uncommon for some teeth to be shorter when new...

posted by Al__S [874 posts]
6th September 2013 - 8:44

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Al__S wrote:
Do remeber when thinking that there are teeth "missing" on your chain rings rthat it is not uncommon for some teeth to be shorter when new...


posted by thorolf [67 posts]
6th September 2013 - 10:16

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Jesus what are you lot doing with your bikes! - I ride 180 miles a week and havent changed chains for over two years. The load is split over 3 bikes but all the same...go with how it feels not what manufacturers say.

posted by NeilXDavis [118 posts]
6th September 2013 - 11:49


something that does a huge amount of damage to the drivetrain is:

-cleaning the chain with aggressive cleaning products or mechanisms (like chain cleaning machines) that strip out the lubricant inside the rollers. Chain manufacturers like Shimano and KMC specifically advise against using any solvents or cleaning machines as it just strips lube out of the chain rollers and dramatically reduces chain life. Once this internal lube is removed, its hard to replace.

-running a very dirty drivetrain, this simply is a grinding paste and will wear chain, cassette cogs, chainrings and derailleur pulley wheels in short order

-abusing the drivetrain with poor gear choices like big/big combos or riding constantly on the 11t cog at the rear, shifting under heavy load or forcing bad shifts going up into sudden climbs

on my own bikes (I am a workshop manager in a high-end bike shop) I will never clean my drivetrain with anything more aggressive than warm water and mild detergent, using a nylon brush and tooth brush.

Then rinsed with warm water, allowed to air dry and dry chain lube carefully applied to each roller on the chain, then back pedalled on a workstand through a clean rag to remove excess lube

between washing sessions, I would wipe the chain with a clean rag whilst back pedalling (pulling the chain down, up or applying side pressure with rag) on a workstand whilst in a gear combo giving a neutral chain line; apply a small amount of lube to a new rag, then backpedal again whilst using the rag, you can clean much surface dirt off the chain using the method

found this dramatically increases drivetrain life. Will check chain stretch every couple of weeks using Park chain checker and replace at recommend intervals.

something to bear in mind is that a spotlessly clean chain, is generally either a brand new chain, or a chain that has been abused using a parts washer or aggressive solvents in a chain cleaning machine, and external appearance is no indication of long-term durability when a chain is stripped of internal lubricants in an effort to "clean" the drivetrain

posted by hampstead_bandit [447 posts]
6th September 2013 - 21:09


I disagree about never using chain baths and solvents in case you flush out the internal lube, it's not hard to replace.

Besides, once you get a really filthy chain, fine grit or grinding gunk in between the plates you need to flush it out. No amount of wiping is going to remove it.

If you clean the chain thoroughly with a degreaser, rinse with very hot water - you need to take it off to do this obviously - dry, then relube each link at the join with wet or dry lubricant, then back pedal the chain round then the lube will work it's way inside the links easily.

joemmo's picture

posted by joemmo [1093 posts]
6th September 2013 - 22:23


joemmo wrote:
I disagree about never using chain baths and solvents in case you flush out the internal lube, it's not hard to replace.

I disagree, it is hard to replace, and it's why the chain manufacturers always recommend against using degreasers, chain baths and so on.

No matter how much lube you dribble onto your shiny chain the physics means it can't fully replace the stuff you stripped out with degreaser.

Simon E's picture

posted by Simon E [2370 posts]
7th September 2013 - 10:27