Should I replace my large chain ring?
#1
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Should I replace my large chain ring?
Should I replace my largest chain ring in the front? I can't quite tell if they are spiky enough or look like shark fins? I also included a picture of my cassette since I read that that is supposed to wear out faster but it doesn't seem to be? Please let me know if you think I should replace that too. Everything is original to the bike and the bike (2012 Trek Lexa) has maybe 10,000 miles on it? It's hard to say honestly though since I haven't been keeping track of the mileage until recently. TIA!







#2
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10,000 easy miles is a lot different than 10,000 hard & neglected miles.
Some people have a favorite cog. This is the one most likely to skip under load. If you are someone who uses all your cogs, you'll get more miles.
Big gears (larger diameter) are under less tension, which makes for less friction & less wear. The smallest chainring is the most likely to wear out first unless it is a much stronger material than the others or used significantly less than the others. Chain-suck where the teeth are too tall to cleanly release the chain is the biggest tell-tale sign that a replacement is necessary.
I wouldn't change anything until a fresh or relatively unworn chain misbehaves.
Some people have a favorite cog. This is the one most likely to skip under load. If you are someone who uses all your cogs, you'll get more miles.
Big gears (larger diameter) are under less tension, which makes for less friction & less wear. The smallest chainring is the most likely to wear out first unless it is a much stronger material than the others or used significantly less than the others. Chain-suck where the teeth are too tall to cleanly release the chain is the biggest tell-tale sign that a replacement is necessary.
I wouldn't change anything until a fresh or relatively unworn chain misbehaves.
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#3
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If you want to you can change it, but any remaining mileage on that ring will let you go that much further before adding to your maintenance expenses.
I'd just let it go until your chain starts to skip over the ring when you put some power into the pedals. Usually that happens after putting a new chain on. But if you do something that is so important you don't have time for such failures such as competitions or races, then change it.
You have been changing your chains regularly when they measure as worn haven't you?
I'd just let it go until your chain starts to skip over the ring when you put some power into the pedals. Usually that happens after putting a new chain on. But if you do something that is so important you don't have time for such failures such as competitions or races, then change it.
You have been changing your chains regularly when they measure as worn haven't you?
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#4
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10,000 easy miles is a lot different than 10,000 hard & neglected miles.
Some people have a favorite cog. This is the one most likely to skip under load. If you are someone who uses all your cogs, you'll get more miles.
Big gears (larger diameter) are under less tension, which makes for less friction & less wear. The smallest chainring is the most likely to wear out first unless it is a much stronger material than the others or used significantly less than the others. Chain-suck where the teeth are too tall to cleanly release the chain is the biggest tell-tale sign that a replacement is necessary.
I wouldn't change anything until a fresh or relatively unworn chain misbehaves.
Some people have a favorite cog. This is the one most likely to skip under load. If you are someone who uses all your cogs, you'll get more miles.
Big gears (larger diameter) are under less tension, which makes for less friction & less wear. The smallest chainring is the most likely to wear out first unless it is a much stronger material than the others or used significantly less than the others. Chain-suck where the teeth are too tall to cleanly release the chain is the biggest tell-tale sign that a replacement is necessary.
I wouldn't change anything until a fresh or relatively unworn chain misbehaves.
#5
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Thread Starter
If you want to you can change it, but any remaining mileage on that ring will let you go that much further before adding to your maintenance expenses.
I'd just let it go until your chain starts to skip over the ring when you put some power into the pedals. Usually that happens after putting a new chain on. But if you do something that is so important you don't have time for such failures such as competitions or races, then change it.
You have been changing your chains regularly when they measure as worn haven't you?
I'd just let it go until your chain starts to skip over the ring when you put some power into the pedals. Usually that happens after putting a new chain on. But if you do something that is so important you don't have time for such failures such as competitions or races, then change it.
You have been changing your chains regularly when they measure as worn haven't you?
#6
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Shhhhh! don't use the word "stretched" in the same sentence with chain. Some people here take the word stretched too literally. And they get very confrontational about how a person can't stretch a chain.
Wear is a much safer term around here! <grin>
For 11 speed chains, I've started replacing them when the pin closest to the 12" mark gets to be about 1/16" further. For the old bikes with 7 speeds and less, I never worried much about either chain or cogs, just replaced when one didn't work with the other.
Chains are about the only thing with the drive train that I do preventative maintenance on. I'm happy to let the rings and cogs go until they show me issues. Which is usually the chain skipping or slipping on them when putting some power into the pedals to accelerate rapidly from a stop.
Wear is a much safer term around here! <grin>
For 11 speed chains, I've started replacing them when the pin closest to the 12" mark gets to be about 1/16" further. For the old bikes with 7 speeds and less, I never worried much about either chain or cogs, just replaced when one didn't work with the other.
Chains are about the only thing with the drive train that I do preventative maintenance on. I'm happy to let the rings and cogs go until they show me issues. Which is usually the chain skipping or slipping on them when putting some power into the pedals to accelerate rapidly from a stop.
Last edited by Iride01; 08-07-22 at 11:44 AM.
#7
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Thread Starter
Thanks for all the info by the way! By cogs here do you also mean the gears on the cassette too? Because I think this might be happening on one of those too. One of my middle gears in the back tends to skip under load, I know that, but I just figured my indexing was off or something?
#8
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Thread Starter
If you want to you can change it, but any remaining mileage on that ring will let you go that much further before adding to your maintenance expenses.
I'd just let it go until your chain starts to skip over the ring when you put some power into the pedals. Usually that happens after putting a new chain on. But if you do something that is so important you don't have time for such failures such as competitions or races, then change it.
You have been changing your chains regularly when they measure as worn haven't you?
I'd just let it go until your chain starts to skip over the ring when you put some power into the pedals. Usually that happens after putting a new chain on. But if you do something that is so important you don't have time for such failures such as competitions or races, then change it.
You have been changing your chains regularly when they measure as worn haven't you?
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Thanks for all the info by the way! By cogs here do you also mean the gears on the cassette too? Because I think this might be happening on one of those too. One of my middle gears in the back tends to skip under load, I know that, but I just figured my indexing was off or something?
Cogs are on the cassette in the rear. Chain rings are on the crank in front. Measure chain wear with a ruler and when it reaches 1/16" in a nominal 12" section, replace the chain. If the chain skips on the cogs when you pedal hard then the cassette may need replacing. You can ride a couple 100 miles and if the chain is still skipping, replace the cassette. If the new chain skips easily on the cassette, replace the cassette immediately. Your chain rings are worn but not seriously so. Put a new chain on the chain ring and see how much it "rides up" as it wraps around. That is the best indicator of chain ring wear.
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No, your rings don’t look worn. They still have the original machining present. Modern chainring teeth can have a lot of different shapes depending on where the teeth are on the ring in relation to the lift pin. Perhaps you shouldn’t ride to the point where the chainring teeth look like the ring on the left but yours can go quite a while longer.
worn vs unworn by Stuart Black, on Flickr

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Stuart Black
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
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#11
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I wouldn't.
My usual protocol is to replace my chain yearly, about 4k miles. My cassette has about 20k miles and I plan to replace it soon. I keep everything very clean and lubed and I am certainly not the biggest or strongest guy around.
Chainrings? Rarely, if ever.
My usual protocol is to replace my chain yearly, about 4k miles. My cassette has about 20k miles and I plan to replace it soon. I keep everything very clean and lubed and I am certainly not the biggest or strongest guy around.
Chainrings? Rarely, if ever.