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Thread: Broken Chain?

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    Broken Chain?

    As soon as I stood up and started to pedal, it popped and shot out off the back of the bike. Is this a common problem? This happened to me last summer and I can't figure out what is going on. The chain I broke last year was a shimano, so I chocked it up to improper installation, but yesterday I was riding on a sram with less than 300 miles on it. Not to mention the fact that the link that blew out had never been removed, it was as the factory assembled it.

    I admit that this is a winter bike I am running as a single speed, so the chain wasn't meticulously maintained but after 300 miles?

    Am I just too strong for the modern 8 speed chain, or am I missing something?

    Edit: don't know if it makes any difference, but I weigh in at 230lbs, and my steel frame commuter adds ~25lbs so I am pushing a lot of weight around town.
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    Last edited by ryanwood; 02-13-10 at 10:46 AM.

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    cab horn
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    Judging by the condition of that chain I wouldn't be surprised. There's corrosion everywhere. You must be better than a world class olympic track sprinter if you think you can break a properly installed 8 speed chain on a bike that doesn't shift.
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    Holy smoke, how did you get that chain in that condition after 300 miles? It looks like its been stored under water -- salt water at that. Wipe your chain after every ride. Lube regularly.

    I've weighed as much as 240+ lbs (now I onlt weigh 195 :-)) and ride bikes in all kinds of weather. I have not ever broken a chain like that.
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    Old fart JohnDThompson's Avatar
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    Do you store your bike outside? That chain looks pretty rusty. If you can't bring the bike inside, make sure you keep the chain well-lubricated to prevent rust formation. Even so, you should expect to replace it fairly often if it lives outside.

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    The rust on the chain is surface rust that developed because I didn't clean it after yesterday's commute when it broke. The bike stays in the garage every night, and the chain gets oiled every other day, and every day it is exposed to excessive salty water.

    Apparently the picture accentuates the rust because that chain still runs as smooth as butter.

    My biggest concern is that I converted my shimano freehub to a single speed so I have a stack of spacers and I think my chain line is good, but I didn't know if a slightly wonky line could cause the chain to break prematurely. The chain was cheap and I don't mind replacing it because of rust if it means I can still commute through the winter, but I don't want it to break because I didn't adjust my spacers correctly.

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    The chain looks over-cleaned and under-lubricated. In the winter with salt and ice conditions you want to keep enough lubricant coating the chain so the salt water never gets to the metal.

    If the chain line looks reasonable then that's not a likely cause of the failure. Have you held a straight edge along the chainring to see if it points correctly at the cog? I fairly regularly ride in the not-recommended large/large combination with a visibly offset chain line and have never experienced a broken chain, so I'd expect that it would have to be way off before you get such problems. I suspect you just had the bad luck to get a chain with a manufacturing defect since the amount of rust visible is not enough to cause a failure.

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    Quote Originally Posted by ryanwood View Post
    The rust on the chain is surface rust that developed because I didn't clean it after yesterday's commute when it broke. The bike stays in the garage every night, and the chain gets oiled every other day, and every day it is exposed to excessive salty water.

    Apparently the picture accentuates the rust because that chain still runs as smooth as butter.

    My biggest concern is that I converted my shimano freehub to a single speed so I have a stack of spacers and I think my chain line is good, but I didn't know if a slightly wonky line could cause the chain to break prematurely. The chain was cheap and I don't mind replacing it because of rust if it means I can still commute through the winter, but I don't want it to break because I didn't adjust my spacers correctly.
    Chainline would render your bike unusable before it is bad enough to cause a premature breakage problem like that. The chainline would have to be as extreme as a cross-chain triple/rear 10. big/big big/small. Your bike would not work as a singlespped with that large of a chainline error. Since you're running a singlespeed I highly recommend replacing it with a KMC inox stainless chain. ~ $20 MSRP.

    The only thing you can say about that chain failure is that it's unusual.

    Did you install it by punching a pin partially out and reusing it to connect?
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    Old fart JohnDThompson's Avatar
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    Quote Originally Posted by ryanwood View Post
    My biggest concern is that I converted my shimano freehub to a single speed so I have a stack of spacers and I think my chain line is good, but I didn't know if a slightly wonky line could cause the chain to break prematurely. The chain was cheap and I don't mind replacing it because of rust if it means I can still commute through the winter, but I don't want it to break because I didn't adjust my spacers correctly.
    No, chainline problems won't cause the chain the to break prematurely. Think about it: the chain on a derailleur bike spends the vast majority of its life in a non-aligned state. The problem with chainline on a single speed or fixed gear bike is not breakage, but simply that there is nothing to prevent the chain from dropping off the cog. When the chain is not aligned, this is much more likely to happen. On a single speed this is annoying; one a fixed gear it can be dangerous.

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    Real Men Ride Ordinaries fuzz2050's Avatar
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    Quote Originally Posted by JohnDThompson View Post
    . On a single speed this is annoying; one a Brakeless fixed gear it can be dangerous.
    Sorry, just had to clarify.

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    Well, dropping a chain on even a braked fixed gear will probably lock up the wheel in a couple of milliseconds, even if the chain is dropped in the front. Probably more than annoying, but not necessarily up to dangerous, unless you happen to be cornering at the tim.

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    Old fart JohnDThompson's Avatar
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    Quote Originally Posted by Teemu Kalvas View Post
    Well, dropping a chain on even a braked fixed gear will probably lock up the wheel in a couple of milliseconds, even if the chain is dropped in the front. Probably more than annoying, but not necessarily up to dangerous, unless you happen to be cornering at the tim.
    Or riding in traffic. Or on a velodrome.

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    Quote Originally Posted by operator View Post
    Did you install it by punching a pin partially out and reusing it to connect?
    which do you recommend? that, or masterlink? all things being equal (and properly installed/maintained).

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    Senior Member coldfeet's Avatar
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    300 miles, but how many years? Definitely need more/better lube. You say you're 230 lbs, How strong are your legs? What ratio are you pushing? Were you going uphill at the time? I've snapped one chain in ...18 years? Of course, I'm not that strong. Even so, startling to see a chain with 300 miles go like that.

    As a point of interest, can you measure a length of that chain? I'd be interested to know what 12 full links measures when pulled out straight.

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    First of all, I hope you saved the chain because I'd like to have a sample length including the broken end.

    Almost every broken chain I see is the result of aggressive shifting pushing the plates over the ends of the pins. You have a completely different type of failure, namely a cracked plate. The crack is in a direction that implies that it didn't fail from excess load so it's an interesting case study.

    It's impossible to know for sure, but I'll venture that corrosion (rust) was the direct cause of the break. There are multiple mechanisms at work. We all know that rust weakens steel parts, but not many consider that the process of rusting also swells them. In this case, if the pin or the edge of the outer plate at the pin rusted it would swell stressing the plate in a way similar to how water freezing in pipes causes them to burst. There's also the possibility that chlorine ions in the salt made the plate more brittle compounding the problem.

    This is a reminder of the importance of keeping water, especially salt water out of and off of your chain. Chain failure is no fun, and almost always happens under the worst of circumstances. This isn't Murphy's Law, but simply because a weakened chain primed to break, will do so when under a peak tension load.

    Good luck with the replacement, and if you're interested, PM me to arrange a swap of some chain oil for a sample of your chain.
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    Senior Member MudPie's Avatar
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    FWIW:

    1) SRAM had a recall on their 10-spd chains about a year ago, but this shouldn't affect your 8-spd chain.
    2) There have been reports of soaking chains in Simple Green adversely affects chains.

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    no stretching, like I said the chain is brand new. The city here puts down a nasty mixture of sand and salt down onto the road to work over the snow. This mixture presents big problems for me because if I pile on extra lube to keep the salt water out, the sand sticks to the oil. The worst part is that the extra oil attracts the sand which still carries dry salt, there by making the whole thing an exercise in futility. That is where I am right now, I started with extra lube to keep the oil out and get salty sandy oil. Then I tried a less sticky oil, which washes off and I get salt water into to chain.

    Any other winter riders out there have any good chain solutions? or should I just get used to destroying a chain every winter?

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    cab horn
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    Quote Originally Posted by MudPie View Post
    FWIW:

    1) SRAM had a recall on their 10-spd chains about a year ago, but this shouldn't affect your 8-spd chain.
    2) There have been reports of soaking chains in Simple Green adversely affects chains.
    1) No they didn't, they had a recall on the 10-speed powerlock connector. It had nothing to do with the chains.
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    Quote Originally Posted by bionnaki View Post
    which do you recommend? that, or masterlink? all things being equal (and properly installed/maintained).
    Masterlink.

    If you look closely at your chain those pins are double peened - you should not reusing pins. You cannot re-use pins on pretty much any 7-11 speed chains. They either come with a special connecting pin or they come with a 'masterlink' type deal. The chains WILL fail if pins are re-used in such a fashoin.
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    cab horn
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    Quote Originally Posted by ryanwood View Post
    no stretching, like I said the chain is brand new. The city here puts down a nasty mixture of sand and salt down onto the road to work over the snow. This mixture presents big problems for me because if I pile on extra lube to keep the salt water out, the sand sticks to the oil. The worst part is that the extra oil attracts the sand which still carries dry salt, there by making the whole thing an exercise in futility. That is where I am right now, I started with extra lube to keep the oil out and get salty sandy oil. Then I tried a less sticky oil, which washes off and I get salt water into to chain.

    Any other winter riders out there have any good chain solutions? or should I just get used to destroying a chain every winter?
    The stainless chain i have recommended will help greatly. They are used by toronto messengers - our roads get salted and slushy during the winter. Highly recommended.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

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    Quote Originally Posted by ryanwood View Post
    The city here puts down a nasty mixture of sand and salt down onto the road to work over the snow. This mixture presents big problems for me because if I pile on extra lube to keep the salt water out, the sand sticks to the oil. The worst part is that the extra oil attracts the sand which still carries dry salt, there by making the whole thing an exercise in futility. That is where I am right now, I started with extra lube to keep the oil out and get salty sandy oil. Then I tried a less sticky oil, which washes off and I get salt water into to chain.

    Any other winter riders out there have any good chain solutions? or should I just get used to destroying a chain every winter?
    I had the same situation when I lived in southern Michigan where they love to spread salt on the roads. I think you would have been better off with your first approach even though you get a chain that looks really gross with all the grit stuck on the outside. But as long as it remains well lubricated, the grit particles are free to move around and will quickly get pushed to the outside of the chain as the links pivot. Once on the outside the grit no longer does any harm to the chain and the lube should keep the salt away from the metal. That's what I did for my winter riding in Michigan and never experienced any chain problems - but the chain sure looked filthy with all the grit stuck to the outside. Looked bad but worked much better than using thinner lubes that washed off and left the chain unprotected much of the time. The chains remained in good condition under the layer of grit and grime and cleaned up nicely when I'd get around to it.

    Then I solved the problem by moving to the SF Bay area.

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