EAI cog wear on teeth? (bare metal exposed?)
03-14-06, 09:55 PM
#1
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I noticed that my Nashbar Recumbent chain says "KMC Narrow Z-40" !
So I looked at my cog, and then every other tooth, there is a metal line where there has been evident wear on the cog. You know, the cog is a dark brown color, but every other tooth has a line that shows wear that exposes bare grey metal. Chain, cog, chainring, are all brand new, and chainline is perfect.
I'm just curious, do you have this metal wear on every other tooth on your cogs? Or is this chain really "narrow" and causing these problems? I have noise in the chainring and cog, too.
So I looked at my cog, and then every other tooth, there is a metal line where there has been evident wear on the cog. You know, the cog is a dark brown color, but every other tooth has a line that shows wear that exposes bare grey metal. Chain, cog, chainring, are all brand new, and chainline is perfect.
I'm just curious, do you have this metal wear on every other tooth on your cogs? Or is this chain really "narrow" and causing these problems? I have noise in the chainring and cog, too.
03-14-06, 10:03 PM
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perhaps the cog is on at a slight angle. that would cause it to oscillate back and forth every rotation and give you the wear on every other tooth.
just a guess though
just a guess though
03-14-06, 10:11 PM
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Well when you think about it, every other link on the chain is the narrow one, and these make contact with the teeth on the cogs. It seems that mine might be too narrow or something so they stick and create extra friction..
03-14-06, 10:29 PM
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I bet your cog has an even number of teeth, right?
The scuffing on the sides of the cog is just from the chain riding against it over time. You will probably notice more suffing on one side of the cog than the other, which is a sign that although your chainline may be as perfect as you can get it, you never really get the axle perfectly perpendicular to the chain, so the cog is riding at a slight angle to the chain, causing the chain to ride over to one side of the cog's teeth and wear the other side.
An odd number would cause the cog to wear evenly, and an even number will mean that any one gap between cog teeth will always see the same kind of chain link (wide or narrow). The narrow links are the only ones that can touch the cog. If you want to even out the wear, just loosen your axle and index the chain ahead by one tooth on the rear cog. The same is true if you have an even toothcount on your ring.
The scuffing on the sides of the cog is just from the chain riding against it over time. You will probably notice more suffing on one side of the cog than the other, which is a sign that although your chainline may be as perfect as you can get it, you never really get the axle perfectly perpendicular to the chain, so the cog is riding at a slight angle to the chain, causing the chain to ride over to one side of the cog's teeth and wear the other side.
An odd number would cause the cog to wear evenly, and an even number will mean that any one gap between cog teeth will always see the same kind of chain link (wide or narrow). The narrow links are the only ones that can touch the cog. If you want to even out the wear, just loosen your axle and index the chain ahead by one tooth on the rear cog. The same is true if you have an even toothcount on your ring.
03-15-06, 05:14 AM
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Holy ****, the crap you people worry about.
Go ride the bike.
Go ride the bike.
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This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.
This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.
03-15-06, 07:20 AM
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How wide is your cog? How wide is the chain? Unless the cog is 3/32" and the chain is at least 3/32" wide, you will probably have the problem you are describing.
03-15-06, 01:09 PM
#12
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This article by Sheldon Brown explains how using even number cog/chainring combinations on SS bikes can extend chain life. In the process it also explains why only every other tooth shows the wear marks.
https://sheldonbrown.com/chain-life
If it's just polished, I wouldn't worry about it at all, that's perfectly normal. If you actually see signs of wear such as a ridge or notch, then you probably need a different chain.
https://sheldonbrown.com/chain-life
If it's just polished, I wouldn't worry about it at all, that's perfectly normal. If you actually see signs of wear such as a ridge or notch, then you probably need a different chain.
