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Discussion Starter · #1 ·
Hey Guys, My chain starting skipping on me the last few rides. I bought the bike in March and I'm not a small dude. Is it realistic for the chain/cassette to be worn out already. I'm gonna bring my bike to the shop with me tomorrow and use the "Chain Checker" on it, and check the cassette for wear.

I actually broke the chain a few weeks ago and am currently using a SRAM Powerlink.
 

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Formerly of Kent
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The size of the rider has nothing to do with how quickly a chain wears down.

A pro's training bike will go through chains monthly; it's a matter of how much power you're producing, and how long you're doing it.

I bought my Giant Anthem X2 in late April, and despite the fact that I ride my 29er a fair bit as well, the chain is coming up for replacement rather quickly.
 

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Older than I feel
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My rule of thumb is, if I can measure any stretch with a standard 12" ruler, the chain is done.

But then I also believe in washing chains off the bike in a good degreaser (e.g. Simple Green) and re-lubing every few rides.
 

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seems a bit overkill.. kinda like doing 1000 mile oil changes on a car! how often do you change chains? id imagine they stretch measurably within a couple hundred miles.

at 1/16th stretch you're not damaging anything at all.. thats the generally accepted time to toss your chain. a "chain checker" isnt necessary, chains should be measured with a ruler or tape measure.
 

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Looks like all chains are not created equal.

I just replaced a chain that I had on a singlespeed bike for 4 weeks. It stretched in 200 to 300 miles of riding: mainly relaxed commuting.

Now that bike (too) has a Shimano CN-7701 on it. I've had good luck with those before. Before installation, I wiped the chain exterior with a rag that had some degreaser in it, and applied some waxy Weldtite lube.
 

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I'm afraid to imagine how many chains are prematurely replaced because of inaccurate chain checking (any brand) tools.

Measure your chain for stretch under slight tension with a 12" ruler, less than 1/16" you've miles to go, 1/16" to 1/8" consider replacing to protect the cassette from undue wear, over 1/8" replace immediately, though it may be too late for certain cogs on your cassette.

Don't compare your chain life to anybody else's. There are too many variables, including terrain, lubrication, weight and strength of rider, and chain quality. Stronger or heavier riders, doing lots of climbing will eat up chains, especially if they don't keep them properly lubed, while smaller riders in the plains can get away with murder and their chains will seemingly last forever.

Given the legitimate differences in conditions, compounded by various opinions of when a chain is toast and the inaccuracy of chain checking devices, I'm not at all surprised to hear of differences of more than 10 to 1 in reported chin life.
 

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FBinNY said:
I'm afraid to imagine how many chains are prematurely replaced because of inaccurate chain checking (any brand) tools.
I'd guess not too many. Most chain checking tools I know of are very generous in the amount of stretch they consider "good".

FBinNY said:
Measure your chain for stretch under slight tension with a 12" ruler, less than 1/16" you've miles to go, 1/16" to 1/8" consider replacing to protect the cassette from undue wear, over 1/8" replace immediately, though it may be too late for certain cogs on your cassette.
While that's the conventional wisdom, I'm much more conservative than this because, as a wise roadie friend once convinced me, chains are cheap and cassettes and chainrings are expensive. How many decent chains can you buy for the price of a new cassette or set of rings? You can get a new SRAM PC-971 chain for $20 if you know where to shop. When was the last time you saw an X.9 or XT cassette for less than 3 times that price?

But it's really a matter of priorities. I'd rather spend time cleaning, lubing, and replacing chains than deal with chain skipping and spend money replacing other drivetrain parts. Other people may prefer to spend money rather than time. Who am I to say?
 

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Le Duke said:
The size of the rider has nothing to do with how quickly a chain wears down.
.
Yes it does. It takes more force to accelerate a heavier rider a given amount than a lighter rider. That all goes through the chain.
 

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Discussion Starter · #11 ·
chucko58 said:
\You can get a new SRAM PC-971 chain for $20 if you know where to shop.
Or a fraction of that if you work at a shop :thumbsup:

Anyways I did some investigating and my chain seems to be fine, HOWEVER, my axle is bent, could that have anything to do with it?
 

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kapusta said:
Yes it does. It takes more force to accelerate a heavier rider a given amount than a lighter rider. That all goes through the chain.
300w of power is 300w of power. Just because a smaller rider goes faster with it than a larger rider, doesn't mean that the forces are any lesser or greater.

A pickup truck and a sports car both produce 300whp, and 300lb/ft of torque. Which one do you think will accelerate faster? I'm guessing the sports car.

Who do you think produces more power, a 150lb pro, or a 250lb dude who rides twice a week and has never turned the pedals in anger? I'm going with the person who is paid to ride a bicycle. Call me crazy, but that's my theory, and I'm sticking to it.
 

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Le Duke said:
300w of power is 300w of power. Just because a smaller rider goes faster with it than a larger rider, doesn't mean that the forces are any lesser or greater.

A pickup truck and a sports car both produce 300whp, and 300lb/ft of torque. Which one do you think will accelerate faster? I'm guessing the sports car.

Who do you think produces more power, a 150lb pro, or a 250lb dude who rides twice a week and has never turned the pedals in anger? I'm going with the person who is paid to ride a bicycle. Call me crazy, but that's my theory, and I'm sticking to it.
You and Kapusta are both looking at opposite sides of the same coin. Both power and payload affect drivetrain wear though in slightly different ways.

While power might be a predictor of torque, it isn't automatic. Power is a question of work over time, and can be manifested as high speed rather than high strength. A light fit rider might be able to produce higher power, yet not be nearly as strong as a larger less fit rider who would be able to produce more torque. The faster rider would win a race, but the heavier rider would win a tug-o-war, or arm wrestling match.

Since you like car analogies, imagine we put a 450hp engine into both a high performance sports car and a light truck with a tow hitch. Which do you think would need a heavier duty drive train? Sure the sports car is faster, but there's a reason they beef up drive train components when they sell tow packages for light trucks, even while using the same engine.

BTW- no matter how fit or fast you are, don't get into a bar fight with someone who weighs twice as much as you, or you're likely to get a tough lesson in the difference between fitness and strength.
 

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Le Duke said:
300w of power is 300w of power. Just because a smaller rider goes faster with it than a larger rider, doesn't mean that the forces are any lesser or greater.

A pickup truck and a sports car both produce 300whp, and 300lb/ft of torque. Which one do you think will accelerate faster? I'm guessing the sports car.

Who do you think produces more power, a 150lb pro, or a 250lb dude who rides twice a week and has never turned the pedals in anger? I'm going with the person who is paid to ride a bicycle. Call me crazy, but that's my theory, and I'm sticking to it.
I think you are only looking at one side of the issue, but completely ignoring the other.

I never said a more fit person does not put down more power. What you seem to be missing here is that heavier people at any level put down more power than lighter people at that same level. Were this not true, the lightest people would always be the fastest (as your car example points out). If two people, be them pro's or weekend joe's are equal in fitness and strength, you would expect them to be about the same speed, correct? OK, if one is heavier and accellerates/climbs/whatever the same as the first, which one had to put more power down to do it? It is going to be roughly proportional to their weight.

When I ride with a group, we can range from 125 lbs to 220, and we all are around the same speed. Of course the 220 lb guy is putting A LOT more tension on the chain then the 125 lb woman on a steep climb.

And I'm not so sure about the comparison you are making in your last paragraph. Think about this, if the racer really does put more power down, then he should be able to strap an extra 100 lbs to his bike and still beat the weekend warrior up a hill. Now, I'm sure there are some racers who could beat some ww's in this scenario, but my point is that someone can be a much stronger/fitter rider, but not be producing more power than a less fit/slower rider that weighs a lot more, even if he is winning the race to the top of he hill.

Ever notice how much weight a really overweight person can leg press at the gym even when they are just starting out?

Sorry, but your contention that someones weight has nothing to do with chain wear is just dead wrong. It is a MAJOR factor that simply cannot be ignored.
 

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kapusta said:
I think you are only looking at one side of the issue, but completely ignoring the other.

I never said a more fit person does not put down more power. What you seem to be missing here is that heavier people at any level put down more power than lighter people at that same level. Were this not true, the lightest people would always be the fastest (as your car example points out). If two people, be them pro's or weekend joe's are equal in fitness and strength, you would expect them to be about the same speed, correct? OK, if one is heavier and accellerates/climbs/whatever the same as the first, which one had to put more power down to do it? It is going to be roughly proportional to their weight.

When I ride with a group, we can range from 125 lbs to 220, and we all are around the same speed. Of course the 220 lb guy is putting A LOT more tension on the chain then the 125 lb woman on a steep climb.

And I'm not so sure about the comparison you are making in your last paragraph. Think about this, if the racer really does put more power down, then he should be able to strap an extra 100 lbs to his bike and still beat the weekend warrior up a hill. Now, I'm sure there are some racers who could beat some ww's in this scenario, but my point is that someone can be a much stronger/fitter rider, but not be producing more power than a less fit/slower rider that weighs a lot more, even if he is winning the race to the top of he hill.

Ever notice how much weight a really overweight person can leg press at the gym even when they are just starting out?

Sorry, but your contention that someones weight has nothing to do with chain wear is just dead wrong. It is a MAJOR factor that simply cannot be ignored.
+1 Weight definitely counts

There's a tendency to conflate various issues when discussing power, strength, speed, fitness, weight and power-to-weight ratios.

There's also an unfortunate bias which causes folks to make assumptions of fitness based on size, or girth or that idiotic federal statistic the BMI or Body Mass Index. While there's a general statistical correlation between fatness and fitness, one cannot logically jump from the general to the specific.

Keeping to the human machine, compare a track sprinter, and a NFL linebacker.
Both have to accelerate and run short distances, so in that way they face similar athletic challenges. Ask yourself, who's likely faster, stronger, or more powerful, and you'll see how speed, strength and power are different.

There's also a difference betwen peak and sustainable power, and while fit riders tend to have more sustainable power, bigger riders tend to be stronger and able to produce higher peak power.

Another way weight comes into play, regardless of power, is in hill climbing. Regardless of speed, it requires more force (and therefore higher chain tension) to move a heavier payload up a hill. In hill climbing chain tension is directly proportional the weight of the rider, regardless of speed.
 

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kapusta said:
And I'm not so sure about the comparison you are making in your last paragraph. Think about this, if the racer really does put more power down, then he should be able to strap an extra 100 lbs to his bike and still beat the weekend warrior up a hill. Now, I'm sure there are some racers who could beat some ww's in this scenario, but my point is that someone can be a much stronger/fitter rider, but not be producing more power than a less fit/slower rider that weighs a lot more, even if he is winning the race to the top of he hill.
I haven't tried it with an extra 100 pounds, but I seem to be able to with an extra 30, no problem. Or pulling another rider who's hanging onto my messenger bag and riding his brakes. Which didn't happen on a climb last night. Certainly not with a group of alcoholic hipsters on the way from a meeting point to a beach. With a gallon of beer in my bag. Definitely not. I'm too hard core for that.

If the 150 (or 130) pound rider and the 220 pound rider are going the same speed, then the 220 pound rider is exerting more force and has a higher power output. But if we're talking about a racer and a weekend warrior, the racer could be going 50% faster and fighting more air resistance, which increases geometrically with speed, he's going to need more than double the power output, which is really all the chain can feel. If there's a hill involved, the racer's also gaining a lot more potential energy on the way up the hill.

If we pretend chain wear is a function of miles over time, the weekend warrior might do 250/month, and a lot of pros do more than that in a week. No wonder they pay for Ultegra on their training bikes.

To go back to the OP's post, it seems a little quick to kill a chain, but if you've been riding off-road a lot or in a dirty place, totally plausible. Is this on the commute bike you got recently?
 

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AndrwSwitch said:
If there's a hill involved, the racer's also gaining a lot more potential energy on the way up the hill.
?
Actually, the heavier person gains more potential energy when climbing to the top of the hill, regardless of how long it takes him to do it.
 

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kapusta said:
Actually, the heavier person gains more potential energy when climbing to the top of the hill, regardless of how long it takes him to do it.
I wasn't clear...

I meant the racer's gaining potential energy in addition to pushing air. I think he's gaining potential energy faster, but certainly by the top of the hill the heavier rider has gained more of it.
 
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