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Discussion Starter #1
Here’s the story……
Check my chain and it just hit’s .75% mark. So of course I hurry and order a new chain before it ruins the rest of the drivetrain. Put it on and guess what…..Yep, skipping on the cassette:madman: :madman: :madman: Now I know when once I buy a new cassette then it will start skipping on the middle ring, then the small and then of course the big. Point is I keep a close eye on the chain length and replace it at as soon as I find out it is worn to the 0.75 point. But I still end up having to buy a new cassette and sometimes the rings. :madmax: What gives? I thought if I kept a close eye on it then I could get by with just replacing the chain and not the cassette and rings.
I have decided to put the old stretched chain back on and run it until I have noticeable problems. Whatever that might be? Then I’ll replace everything at once. Guess I don’t see the need to replace a drivetrain if there is chain stretch but no other problems. If it’s working, don’t fix it!
What’s the opinion of everyone else on this?
 

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Like most rules of thumb, replacing the chain at .75% and not needing to replace the cassette is based on some assumptions:

1) You don't ride most of the time on only one or two of the cassette cogs.

2) The quality of the chain and cassette are comparable.

Assuming a broken chain won't leave you stranded, your plan sounds like the way to go.
 

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Discussion Starter #3
That makes more sense looking at it that way. I was just under the understanding that if the chain was replaced at or near .75 then you wouldn't have to replace the cassette every time. Of course I knew there are exceptions to that due to a number of things. But I see the point to #1. Some gears gets used way more then others.
I usually run a XT cassette with a SRAM 971chain. I usually carry couple extra chain links and a power link in my camelbak so a broken chain is not really a big deal. Guess once I start breaking it often then it will be time to by a new drivetrain.
 

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I'm on my fourth chain on a sram 980 cassette. I don't have a checker. I just measure the chain and replace at 1/16" stretch (in 12"). I'll probably start cycling through the old ones soon.

Are the xt cassettes less durable?
 

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rlouder said:
I'm on my fourth chain on a sram 980 cassette. I don't have a checker. I just measure the chain and replace at 1/16" stretch (in 12"). I'll probably start cycling through the old ones soon.

Are the xt cassettes less durable?
In my experience and the anecdotal ramblings on boards, Shimano cassettes seem to be more durable. SRAM chains are great because they come with reusable powerlinks.

I also have difficulty with getting the chain before it goes to far. I have become much fonder of chain cleaning and have 2-3 spares around. I don't hesitate to swap it. If I think I need to.
 

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So it goes

I've had it go both ways at the .75 mark. Usually, I throw on a new chain and it works fine. Occasionally, I'll get chain skip, and then I do what you're doing- go back to using the old chain and ride everything into the ground. When you start getting chain suck and skips no matter how well everything is cleaned, lubed, and adjusted, it's time to drop some coin and buy an entire drivetrain.
 

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This may be a noob question but i've never had any chain/cassette problems until now. I stopped riding when i was a teen and recently started again and im much heavier and stronger than i used to be, when im on a really steep bit and putting a shed load of load on the pedal the chain can skip.

Can someone tell me how worn is worn on the cassette and chain, and what this .75 mark is?

I hope this is relevent and not to stupid for this post, i dont mean to try to hijack the thread:)
 

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Discussion Starter #8
willtsmith_nwi said:
I have become much fonder of chain cleaning
I do my best to clean and relube the chain after every ride or at least any time it starts to look dirty.

twilk said:
.. when im on a really steep bit and putting a shed load of load on the pedal the chain can skip.

Can someone tell me how worn is worn on the cassette and chain, and what this .75 mark is?
Sounds to me like a worn chain and/or cassette.
0.75% is the amount a chain has stretched. You can buy a handy little chain checker to check the amout of stretch it has. Or you can do it the as rlouder does. From the center of one pin go 12" and you should be on the center of another. If it's over 1/16" then it is recommended to replace the chain.
 

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Noob questions are welcome.

twilk said:
This may be a noob question but i've never had any chain/cassette problems until now. I stopped riding when i was a teen and recently started again and im much heavier and stronger than i used to be, when im on a really steep bit and putting a shed load of load on the pedal the chain can skip.

Can someone tell me how worn is worn on the cassette and chain, and what this .75 mark is?

I hope this is relevent and not to stupid for this post, i dont mean to try to hijack the thread:)
There are 3 areas of wear on a drivetrain:
1. The chain "stretches". (It doesn't actually stretch, but that's another story). As it does, the distance between rollers gets longer. There are ways to measure chain stretch. One of the easiest ways is with a Park Chain Checker tool. When the tool indicates .75%, it's time for a new chain. You can also measure chain stretch with a ruler. The search function is your friend.
2. Over time, the chain ring teeth deform from the constant pressure of the chain rollers digging into them. Running a stretched chain will accelerate the process and render the rings unusable with a new, unstretched chain. Alloy rings and rings with fewer teeth are more susceptible to wear.
3. The same applies for the cassette.

Signs of a worn drivetrain are chain skipping under load and frequent chain suck. Sometimes the problem is caused by a single badly worn part, such as a very worn granny ring. However, if it happens in many gear combos, the whole system is probably shot, and you're better off replacing the whole thing.

You can prolong the life of the drivetrain by keeping it clean, lubricated, well adjusted, avoiding full-load shifting with the FD, and replacing the chain often.
 

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twilk said:
This may be a noob question but i've never had any chain/cassette problems until now. I stopped riding when i was a teen and recently started again and im much heavier and stronger than i used to be, when im on a really steep bit and putting a shed load of load on the pedal the chain can skip.

Can someone tell me how worn is worn on the cassette and chain, and what this .75 mark is?

I hope this is relevent and not to stupid for this post, i dont mean to try to hijack the thread:)

0.75 refers to the percentage the chain is longer than it theoritical length

So on 12 inches that is about 1.5/16 of an inch....

The rule of thumb is change it at 1% stretch....on 12 inches that is 1/8 of an inch...

I get about 5 chains to a cassette...I change a 1% stretch...

Yes it can skip a bit until the new chain gets worn in to the old cassette...

Please don't change your chain at 0.75% stretch, I get more than half the life from 0.75 to 1%.
 
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