Chain stretch after 400 miles WTF?
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Chain stretch after 400 miles WTF?
I have a new road bike that's only done 400 miles and I put the chain wear indicator on it to find that the chain has stretched. Some parts of the chain show no wear while other parts show a lot. It's a KMC DX10sc chain that has never been ridden in the rain, I cleaned and lubed it after ever ride.
I measured it with a ruler and its 1/16 past the 12 inch mark.
My mountain bike chains last longer than this, and that is riding through mud and rain.
Do these thin 10 speed chains wear super fast? I thought I could get 2000 miles easy out of it.
Thanks
I measured it with a ruler and its 1/16 past the 12 inch mark.
My mountain bike chains last longer than this, and that is riding through mud and rain.
Do these thin 10 speed chains wear super fast? I thought I could get 2000 miles easy out of it.
Thanks
#2
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Cleaning and lubing after every ride seems a little excessive. How did you clean it and what kind of lube did you use?
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Cleaned it only with a clean rag. No degreaser or solvents have been used.
Held the rag around the chain and spun the cranks around.
Used Finish Line dry lube.
Held the rag around the chain and spun the cranks around.
Used Finish Line dry lube.
#4
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There two problems, technique and product.
Cleaning the chain requires spraying it with a solvent like WD-40 to wash off the grit and old oil. By not rinsing the chain first, your rag just pushes the dust and grit on the surface into the chain (try wiping your car with a towel before you spray it off with water & soap and you'll see all the scratches in the paint from the dirt and grit that's been sitting on the surface). For your next chain, rinse it with WD-40 first. Just once a week maximum (I do every other week on my high-mileage months). Only after you've hosed off all the grit and old oil, then you wipe off and dry the chain with a clean rag.
Next, "dry" lubes in my experience have not been as good for chain durability. They may be clean, but they also don't lubricate as well as real oil. In my 10-years at a shop and 10-years since, the chains I've replaced the most often that had the lowest mileage has always been the ones using dry , clean lubes. The highest mileage ones had used oil with regular cleaning. I've always gotten 5000-7000 miles out of a chain and they've always been liberally oiled, spun around and had the excess wiped off. Honda recommends using 80-95w gear-oil on their motorcycle chains. I just use 20-50w Mobil-1 since I've always got tonnes of it in my garage.
Cleaning the chain requires spraying it with a solvent like WD-40 to wash off the grit and old oil. By not rinsing the chain first, your rag just pushes the dust and grit on the surface into the chain (try wiping your car with a towel before you spray it off with water & soap and you'll see all the scratches in the paint from the dirt and grit that's been sitting on the surface). For your next chain, rinse it with WD-40 first. Just once a week maximum (I do every other week on my high-mileage months). Only after you've hosed off all the grit and old oil, then you wipe off and dry the chain with a clean rag.
Next, "dry" lubes in my experience have not been as good for chain durability. They may be clean, but they also don't lubricate as well as real oil. In my 10-years at a shop and 10-years since, the chains I've replaced the most often that had the lowest mileage has always been the ones using dry , clean lubes. The highest mileage ones had used oil with regular cleaning. I've always gotten 5000-7000 miles out of a chain and they've always been liberally oiled, spun around and had the excess wiped off. Honda recommends using 80-95w gear-oil on their motorcycle chains. I just use 20-50w Mobil-1 since I've always got tonnes of it in my garage.
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For your next chain try a SRAM pc 951 or 971. I change my chain about aver 1800 miles.
#8
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My Campagnolo ultra narrow Centaur chain is at .25% (12 1/32) with more than 4000 miles. The rollers are wearing more, showing close to .50% with a Park chain checker. I use ProLink Gold lube. I take the chain off and clean it in mineral spirits every few months.
#9
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I suspect that you have measured incorrectly. That chain would take me about 4,000 miles to elongate 1/16" per foot.
I use a precision 12" scale. Place the end on the edge of a pin. When new, the pin at the opposite end will be completely covered by the scale. When the covered pin exposes nearly half it's diameter, you've reached .5% elongation.
I use a precision 12" scale. Place the end on the edge of a pin. When new, the pin at the opposite end will be completely covered by the scale. When the covered pin exposes nearly half it's diameter, you've reached .5% elongation.
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DannoXYZ: Won't the pressurized WD-40 actually force the grit into the rollers?
Rustybucket: Any possibility that your bike has been test ridden for 2000 miles before you bought it?
Anyway, these chain questions always get me back to these words of wisdom. Boy do I miss Sheldon.
Rustybucket: Any possibility that your bike has been test ridden for 2000 miles before you bought it?

Anyway, these chain questions always get me back to these words of wisdom. Boy do I miss Sheldon.
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check it with a ruler. My chain wear indicator says that both my chains are worn, but the ruler says they are perfect. If the 1.0 bit of the chain wear indicator fits in on mine then they are worn to 0.75 (or whatever the numbers are) but the ruler never lies.
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#12
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DannoXYZ: Won't the pressurized WD-40 actually force the grit into the rollers?
Rustybucket: Any possibility that your bike has been test ridden for 2000 miles before you bought it?
Anyway, these chain questions always get me back to these words of wisdom. Boy do I miss Sheldon.
Rustybucket: Any possibility that your bike has been test ridden for 2000 miles before you bought it?

Anyway, these chain questions always get me back to these words of wisdom. Boy do I miss Sheldon.
I use Campy chains, except then I'm doing a chain wear test of another brand. They elongate far less than any other brand. I've used a Campy 10 chain for 6,000 miles and had about 1/16" of elongation over 4 feet of chain (not 1 foot).
One of the key to this little elongation is frequent application of home brew lube. I never go more than 100 miles between lubings and quite often relubed after every 50 mile ride. The later is proabaly overkill, but it didn't hurt.
What I haven't found is any magical way to stop roller wear. Campy chains last longer than any other, but they still expire from roller and side wear.
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I had a KMC 8-speed chain fail a "go/no-go" gauge test at 700 miles. It was the original chain on a hybrid comfort bike. I cleaned and lubed this chain every week, at about 60 to 70 miles weekly. I'm a skinny 62 year-old and hardly put a lot stress on the drivetrain. I chalked it up to poor quality. I get at least 2 to 3 thousand miles on SRAM chains before they fail the stretch test. I vote for poor quality of the original chain and unless you get a repeat performance on another name-brand chain, assume it's not you, it's the chain.
#14
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The way the OP was doing is akin to sprinkling some sand onto a dry rag, then wrapping that around the chain and spinning it through to clean it.
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I have a good steel ruler and measured it like suggested. It has stretched to just under the 1/16 mark. The rollers seem sloppy in some parts as well.
I do climb a few hills doing hill sprints, but I dont mash the gears.
Hopefully it's just a 1 off with this brand of chain. I will pick up a SRAM chain next and try that out.
I do climb a few hills doing hill sprints, but I dont mash the gears.
Hopefully it's just a 1 off with this brand of chain. I will pick up a SRAM chain next and try that out.
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if you try to pull the chain away from the chainring how many links can you lift up? I'm guessing you can't lift it much and that your chain isn't worn out at all.
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The force behing the grit is just its own weight and a little velocity. With a rag, it's the weight of the grit plus whatever hand-forces you're applying by squeezing the rag. The difference is like a magnitude of 1000x. Feel the weight of a grain of sand landing on your skin, compare to how it feels when you grind it in with your finger. Also WD-40 will flush the grit past and out of the chain as well. That's why you want to use liberal amounts so it drips off.
As for the 400 mile thing...it's not completely insane. I had a MTB chain go after about 500 miles, when I'd been riding in dry, dusty conditions. I hadn't been lubing enough, and for a while I was using a dry lube (dumb) because I thought it wouldn't be as bad as a wet lube in the summer when it never rains here.
#18
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Ah yes, that's a subtle unknown trick. Motorcycle guys do this all the time, oil from the inside-out. Then the centripedal force from spinning the chain around the sprocket forces the clean oil through the chain and flings the dirty stuff off the outside.
Last edited by DannoXYZ; 05-04-09 at 04:32 PM.
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#20
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That lifting test means nothing. I get the same kind of lift from a nearly new chain with no measureabel elongations on brand new chain rings.
There are three things to measure for wear. Elongation with a 12" (or longer) rule, roller displacement with calipers and side clearance. Rollers vary from .200 inch to about .210 inch between the roller when new. With Campy chains that seldon elongate by .5%, the roller wear can become excessive. I trash a Campy chain with the roller spacing increases by .035-.040 inch. I've never tossed a chain due to side wear, but I have measured the clearance between inner and outer plates to be .013 inch after 6,000 miles. That about twice the clearance of a new chain. KMC chains do tend to be the loosest or most flexible when new, with about .008 inch of side clearance.
I thought everyone was smart enough to apply their lube to the top of the lower section of chain, but perhaps not. I apply my homebrew lube heavily and use a paper shop towel to catch the excess that I intenionally apply to help flush the old lube from the chain. If you're paying $2 per ounce for boutique lube and only applying 1-2 drops per link, you won't get any flushing. Another reason why cheap home brew makes sense.
There are three things to measure for wear. Elongation with a 12" (or longer) rule, roller displacement with calipers and side clearance. Rollers vary from .200 inch to about .210 inch between the roller when new. With Campy chains that seldon elongate by .5%, the roller wear can become excessive. I trash a Campy chain with the roller spacing increases by .035-.040 inch. I've never tossed a chain due to side wear, but I have measured the clearance between inner and outer plates to be .013 inch after 6,000 miles. That about twice the clearance of a new chain. KMC chains do tend to be the loosest or most flexible when new, with about .008 inch of side clearance.
I thought everyone was smart enough to apply their lube to the top of the lower section of chain, but perhaps not. I apply my homebrew lube heavily and use a paper shop towel to catch the excess that I intenionally apply to help flush the old lube from the chain. If you're paying $2 per ounce for boutique lube and only applying 1-2 drops per link, you won't get any flushing. Another reason why cheap home brew makes sense.
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My homebrew is candles people give me for Christmas with a little Vaseline in it. Melted in a tomato can. Put in chain to soak, all the junk sinks to the bottom. Pull chain out, wipe off, good for another month or two. Reuse wax until it's manky. My chains last for ages and are clean to touch.
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If your cogs and chainrings have a lot of wear on them they will wear out a new chain very quickly.
To get it right you probably have to replace the cogs at the same time as the chain. Possibly even the chainrings if they are really worn. It depends.
To get it right you probably have to replace the cogs at the same time as the chain. Possibly even the chainrings if they are really worn. It depends.
#23
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Well, we already knew that his chain was worn-out. This just shows how much. I suspect that perhaps his cogs are worn out as well, which contributed to the rapid chain wear.
#24
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Then you've got some worn parts somewhere. Chain will only lift off that much if the distance between links is more than 1/2" or distance between leading teeth-edges has decreased to less than 1/2". The wear between all the engaged teeth accumulates and the height you have shows the difference between chain and chainring. Worn-out chainrings with brand-new chain will also show some lifting amount.
Well, we already knew that his chain was worn-out. This just shows how much. I suspect that perhaps his cogs are worn out as well, which contributed to the rapid chain wear.
Well, we already knew that his chain was worn-out. This just shows how much. I suspect that perhaps his cogs are worn out as well, which contributed to the rapid chain wear.
The only way to judge chain wear is measure all of the areas I described. Otherwise you know nothing about whether the chain is really worn out.
Last edited by DaveSSS; 05-05-09 at 10:35 AM.
#25
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I'd like a explanation for why worn chainrings cause the pins and the bushing formed into the inner sideplates to wear faster. That is what causes chain elongation.