Does new chains loosen up on the first ride?- Mtbr.com
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  1. #1
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    Does new chains loosen up on the first ride?

    Will a brand new chain loosen up a bit on the first ride? I installed a new chain and set my tension to just a little tighter than usual, when for a ride, and the chain had loosened a bit without the tensioner moving. I think I've had this happen before, but I'm not sure. Could it be the grease being squeezed from between the pin and plates?

  2. #2
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    yea, it could be a number of things. If each link moves .001" (about 1/3 the thickness of a sheet of paper) due to grease, burs, stretching, etc., it will add up to about 3/32" of chain stretch overall.

  3. #3
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    Quote Originally Posted by bad mechanic
    Does new chains loosen up on the first ride?
    Yes, it does. Nothing to worry about.
    Ride more!

  4. #4
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    Shiny, thank you. I'll actually write it down this time in my Excel file of knowledge.

  5. #5
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    The main cause is the chain settling into the rings. Best case scenario is a new chain and new chainring/cog; but even then you will get settling. The settling is caused by a mismatch between the tooth profiles and the chain. As the chain wears is changes the tooth profiles; with a multi-speed cassette it can be so bad that only the worn chain will work. When you but a new chain on a used chainring/cog the chain will regrind the tooth profile until it matches the profile of the new chain; steel chain vs aluminum chainrings, the chain wins. This re-profiling of the teeth causes the slack or loosing of the chain.
    Just one more rep and I get the toaster!

  6. #6
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    Quote Originally Posted by aka brad
    The main cause is the chain settling into the rings. Best case scenario is a new chain and new chainring/cog; but even then you will get settling. The settling is caused by a mismatch between the tooth profiles and the chain. As the chain wears is changes the tooth profiles; with a multi-speed cassette it can be so bad that only the worn chain will work. When you but a new chain on a used chainring/cog the chain will regrind the tooth profile until it matches the profile of the new chain; steel chain vs aluminum chainrings, the chain wins. This re-profiling of the teeth causes the slack or loosing of the chain.
    Do you know how long this bedding in process takes? Chains are (relatively) cheap, so I change them out before they've stretched 1/16", so there shouldn't be much wear on the chainring and freewheel.

  7. #7
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    Yeah, mine always do. The process is different for everyone based on terrain, riding style and care for your chain.

  8. #8
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    Quote Originally Posted by aka brad
    The main cause is the chain settling into the rings. Best case scenario is a new chain and new chainring/cog; but even then you will get settling. The settling is caused by a mismatch between the tooth profiles and the chain. As the chain wears is changes the tooth profiles; with a multi-speed cassette it can be so bad that only the worn chain will work. When you but a new chain on a used chainring/cog the chain will regrind the tooth profile until it matches the profile of the new chain; steel chain vs aluminum chainrings, the chain wins. This re-profiling of the teeth causes the slack or loosing of the chain.
    I'm not trying to be confrontational or anything of the sort; this is more to clarify my own understanding of the process. Anyway, I thought chain stretching was mostly caused by the chain's rollers wearing within the bushings, which in turn causes the chain to stretch and then begin wearing away the cassette/cog teeth.

    http://www.sheldonbrown.com/chain-life.html

    Correct me if I'm wrong, but isn't the chain tension determined by the size of the base circles (the part excluding the teeth, for lack of a better word) of the chainring/cog, not the teeth profile? That's why different tooth lengths shouldn't affect the tension. Thus, even with aluminum chainrings/cogs, I doubt the chain would wear into the main base circle enough to cause major tension changes in just one ride.

    That's why I've always been told/seen if you change your chain before it elongates too much, you can extend the life of your other drivetrain components considerably.

    Anyway, maybe I'm completely off-base with my conceptualization of chain wear, in which case I'm sure many people will correct me. Cheers!

  9. #9
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    You've got it right. Chains do not stretch at all, at least not with the amount of torque applied by pedaling a bike. With a new chain ISAR has the right answer the factory lub squeezing out between each pin and roller.



    Quote Originally Posted by Rykoh
    I'm not trying to be confrontational or anything of the sort; this is more to clarify my own understanding of the process. Anyway, I thought chain stretching was mostly caused by the chain's rollers wearing within the bushings, which in turn causes the chain to stretch and then begin wearing away the cassette/cog teeth.

    http://www.sheldonbrown.com/chain-life.html

    Correct me if I'm wrong, but isn't the chain tension determined by the size of the base circles (the part excluding the teeth, for lack of a better word) of the chainring/cog, not the teeth profile? That's why different tooth lengths shouldn't affect the tension. Thus, even with aluminum chainrings/cogs, I doubt the chain would wear into the main base circle enough to cause major tension changes in just one ride.

    That's why I've always been told/seen if you change your chain before it elongates too much, you can extend the life of your other drivetrain components considerably.

    Anyway, maybe I'm completely off-base with my conceptualization of chain wear, in which case I'm sure many people will correct me. Cheers!

  10. #10
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    Also your chain ring/crank spider may not be perfectly centered so you could have set the chain tension at the tightest point and subsequently felt the chain at a slacker point.

    I had this with my crank spider

  11. #11
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    Quote Originally Posted by Rykoh
    I'm not trying to be confrontational or anything of the sort; this is more to clarify my own understanding of the process. Anyway, I thought chain stretching was mostly caused by the chain's rollers wearing within the bushings, which in turn causes the chain to stretch and then begin wearing away the cassette/cog teeth.

    http://www.sheldonbrown.com/chain-life.html

    Correct me if I'm wrong, but isn't the chain tension determined by the size of the base circles (the part excluding the teeth, for lack of a better word) of the chainring/cog, not the teeth profile? That's why different tooth lengths shouldn't affect the tension. Thus, even with aluminum chainrings/cogs, I doubt the chain would wear into the main base circle enough to cause major tension changes in just one ride.

    That's why I've always been told/seen if you change your chain before it elongates too much, you can extend the life of your other drivetrain components considerably.

    Anyway, maybe I'm completely off-base with my conceptualization of chain wear, in which case I'm sure many people will correct me. Cheers!
    Okay a correction; the wear is to the main circle and tooth profile; in other words, the wear is within the pocket created by sequential teeth.

    Quote Originally Posted by Sheldon Brown
    As the chain wears, it deforms the sprocket teeth to match the increased pitch of the worn chain. On an odd numbered sprocket, each tooth is alternately in contact with a "stretched" half link and a normal-pitch half link, every other revolution. The "stretched" half links deform all of the teeth, which then no longer mesh properly with the un-stretched half links.

    With even numbered sprockets, only the teeth that correspond to the "stretched" half links get deformed, and by doing so, they work fine with the elongated half links. The alternate teeth don't wear as much, since they are dealing with normal pitch half links.
    In either scenario, even a non-lengthened chain will wear the rear portion of the tooth as you pedal forward; with any lengthening of the chain it will also alter the profile within the tooth pockets to the lengthened profile. With a new chain, it will wear the tooth pocket back to an un-lengthened profile. This will steadily remove more and more material from within the tooth pockets; eventually you will end up with what is referred to as shark finned teeth. A way to mitigate this issue is to flip you chainring with every new chain.
    Just one more rep and I get the toaster!

  12. #12
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    Quote Originally Posted by roybatty666
    Also your chain ring/crank spider may not be perfectly centered so you could have set the chain tension at the tightest point and subsequently felt the chain at a slacker point.

    I had this with my crank spider
    Exactly what happened to me.

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