Chainwheel, Chain and Cassette Worn But Why Replace

[reohn2]

...... I think a lot depends on what sprockets you tend to use most. Some people seem to stay in the smaller sprockets and change on the front a lot, where as my smallest sprocket is hardly used.....

I think you're spot on,less teeth more wear on each tooth.
I run 24/34/46 and a 14-17-19-21-23-25-28-32 cassette the vast majority of use is in 46x23-21-19 with secondary use being 34x28-25-21.I do pedal a brisk 90+ cadence though.

11t cog,what's that then?

[NUKe]

I run a 10 speed drive chain on my commuter, out in all weathers. I have 4 chains which I change out every 500 to a 1000 miles depending upon the conditions. I get between 3500 to 4000 miles out of each chain and around 14 to 16 k out of a set of sprockets. The front chain rings I replaced the biggest one at 27k and the smaller one at 36k
I use engine degreaser from the local motor factors to clean the chains, and Chainsaw bar oil to lube the chains.

recently I bought a small deep fat fryer from Lidl to use an oil bath. The current cleaning regime which is still be refined is to remove the chain . put in a jar with degreaser, shake wash in bowl with water, drop into the deep fat fryer which is on low at 120 c this gets the oil inside and removes any water which has ingressed. Still refining this process.

Chainsaw oil makes a great wet lube, you don't need an oil bath, you can buy in bulk a litre cost around £7 any old lube bottle can be used as dripper. It is very tenacious. it can get a bit sticky if too much is used but wiping off the excess with a rag takes care of this.

[Mick F]

...... I think a lot depends on what sprockets you tend to use most. Some people seem to stay in the smaller sprockets and change on the front a lot, where as my smallest sprocket is hardly used.....

I think you're spot on,less teeth more wear on each tooth.
I run 24/34/46 and a 14-17-19-21-23-25-28-32 cassette the vast majority of use is in 46x23-21-19 with secondary use being 34x28-25-21.I do pedal a brisk 90+ cadence though.
11t cog,what's that then?

This is all very well, but I like my top gear, and in order to get 115" how can I not use a 12t?

If I had a 14t smallest cog, I'd need at least a 60t chainwheel.
If I had that, how could I get a bottom gear of 26" as well?

Looks like I'm stuck with a 12t cog.

[Brucey]

I run a 10 speed drive chain on my commuter, out in all weathers. I have 4 chains which I change out every 500 to a 1000 miles depending upon the conditions. I get between 3500 to 4000 miles out of each chain and around 14 to 16 k out of a set of sprockets. The front chain rings I replaced the biggest one at 27k and the smaller one at 36k <br abp="713">I use engine degreaser from the local motor factors to clean the chains, and Chainsaw bar oil to lube the chains. .

that is pretty good mileage from a 'wet lube + 10s' regime. [I'm sure the oil is good stuff but if the chain is only on the bike for a few hundred miles the main effect is to ensure that your chain is running cleaner than it would be otherwise most of the time. The cleaner the chain, the less important the type of lube is; a perfectly clean chain will get by OK on very little lube.]

Deep fried chains, huh? Wacky!

BTW the quickest way to heat a chain (off the bike) is to use a hot air gun or a hair dryer on it. Once it is nice and warm (as well as dry) the oil will run in nicely.

What model chains and sprockets are you using?

cheers

[NUKe]

I run a 10 speed drive chain on my commuter, out in all weathers. I have 4 chains which I change out every 500 to a 1000 miles depending upon the conditions. I get between 3500 to 4000 miles out of each chain and around 14 to 16 k out of a set of sprockets. The front chain rings I replaced the biggest one at 27k and the smaller one at 36k <br abp="713">I use engine degreaser from the local motor factors to clean the chains, and Chainsaw bar oil to lube the chains. .

that is pretty good mileage from a 'wet lube + 10s' regime. [I'm sure the oil is good stuff but if the chain is only on the bike for a few hundred miles the main effect is to ensure that your chain is running cleaner than it would be otherwise most of the time. The cleaner the chain, the less important the type of lube is; a perfectly clean chain will get by OK on very little lube.]

Deep fried chains, huh? Wacky!

BTW the quickest way to heat a chain (off the bike) is to use a hot air gun or a hair dryer on it. Once it is nice and warm (as well as dry) the oil will run in nicely.

What model chains and sprockets are you using?

cheers

Chains are KMC X10, Sprockets are BBB.

[Chris Jeggo]

My previous posts were based on the fact that I had 'done the experiment' and 'knew the answer', but having contributed them, I started thinking a bit more about what others had posted here, and about correspondence on chain rotation in West Surrey CTC's magazine. There was obviously more to it than I had previously thought. Then came Brucey's erudite reply confirming just that. Thanks, Brucey.

I have now found my maintenance notebook that goes back to 1979 and found that I did the experiment twice, during 1980-82. I was running a 5-speed bike with 14-17-20-24-28t sprockets, the 17 giving my 'normal' gear. I made two Suntour 'Perfect 888' screw-on freewheel blocks (freehubs and their cassettes had yet to appear on the market) each last two chains, more or less the way I described previously. Firstly, with block #1, two Renolds chains lasted 2100 and 2200 miles. Secondly, with block #2, two Shimano Uniglide chains lasted 2100 and 3600 miles.

So, looking at Brucey's list of things that make skipping more likely:
"- a full tooth form on the sprockets" - certainly true of those Suntour sprockets;
"- much heavier wear on a few sprockets than others" - certainly true, and
"- use of small sprockets rather than large ones" - also true, the 14 and 17 sprockets giving most skipping, and the 24 and 28 not at all;
"- chain rollers without much slack in them" - quite possibly the case for those bushed chains, quite different from modern bushing-less ones.

My rear mechanism at the time was a Shimano 'Crane', but I have no idea, at this distance in time, whether that produced "short chain wrap" or "low chain tension from the rear mech". Maybe you know, Brucey.

We live and learn. Maybe I will give chain rotation another try using the modern kit.

[Chris Jeggo]

Five years have whizzed by, but for various reasons it is only now that I have repeated my experiment of replacing a chain without replacing the sprockets, now using the current technology of cassettes and bushingless chains. I had a chain that was less than 0.2% worn at 2200 miles, but when I checked again at 3700 miles it had overshot the advised 0.5% and reached 0.7%. Would that be too much for the old cassette to work without skipping? Nothing to lose by fitting a new chain and giving it a try. Wow! It worked! No hint of skipping on any sprocket, even when pushing hard.

So thanks again, Brucey.

I wonder how many re-usable cassettes I have thrown away. Better not to think about it.

[Brucey]

that sounds like a good result! I'm not sure about chain wrap and tension with a crane mech either; it has been a while!

FWIW the rider makes a big difference here; I have seen folk (spinners not mashers, I'd have said) run chains to (a real) 1% wear and (to my surprise) they still got away with a new chain on those sprockets. With identical components others must change at nearer 0.5% wear if they are to avoid trouble with new-chain skipping.

An elaboration which may improve the chances of re-using a cassette; If a slightly worn cassette won't take a new chain, it will certainly still take one with an intermediate amount of wear. I've not done this often enough to consider it proven beyond all doubt, but after a short period of use with a part (less) worn chain, this seems to reshape the sprocket teeth such that they may once again accept a new chain.

So to this end if you think 0.5 to 0.7% is where you might want to change a chain, but that with the best will in the world, you might let it slip past this amount (that the rate of wear increases as time goes on is not unusual BTW), then I'd suggest keeping a chain worn to 0.2 or 0.3% as your 'get out of jail free card'. This will certainly keep you on the road, and at least gives you a chance of 're-educating' the worn sprockets so that they may accept a new chain after a short while.

cheers