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Discussion Starter · #1 ·
Hi,
I am by no means a bike mechanic and am seeking some advice from those of you who are.

My drivetrain is noisey and unsmooth....kind of like pedaling in a cross over gear. It kind of grinds almost.

It is by far the worst when in the highest gear with chain in big ring in front and small sprocket in cassette. In that combination it really grinds. It is particularly noticeable when you put it on a repair stand and pedal with your hand. You can feel and hear the grinding.

My bike is a Lemond Victoire and I have a Sram Force crankset and BB combined with Dura Ace rear derrailleur and cassette (I think the cassette is a Dura Ace). Chain I believe is Dura Ace too.

Drivetrain is a 9 speed and the crankset is a 9/10 speed compatible.

What do you think is the problem? Is it a function of mixing and matching components? Is it possible my cassette is worn? Or is it more likely a function of derrailleur just not being properly aligned?

It's annoying.

I will bring it to me local shop to get worked on but I hate being without it so I want to get a headstart on what the problem may be before I bring it in.

thanks

Matt
 

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classiquesklassieker
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3,113 Posts
bowler1 said:
Hi,
I am by no means a bike mechanic and am seeking some advice from those of you who are.

My drivetrain is noisey and unsmooth....kind of like pedaling in a cross over gear. It kind of grinds almost.

It is by far the worst when in the highest gear with chain in big ring in front and small sprocket in cassette. In that combination it really grinds. It is particularly noticeable when you put it on a repair stand and pedal with your hand. You can feel and hear the grinding.

My bike is a Lemond Victoire and I have a Sram Force crankset and BB combined with Dura Ace rear derrailleur and cassette (I think the cassette is a Dura Ace). Chain I believe is Dura Ace too.

Drivetrain is a 9 speed and the crankset is a 9/10 speed compatible.

What do you think is the problem? Is it a function of mixing and matching components? Is it possible my cassette is worn? Or is it more likely a function of derrailleur just not being properly aligned?

It's annoying.

I will bring it to me local shop to get worked on but I hate being without it so I want to get a headstart on what the problem may be before I bring it in.

thanks

Matt
It could be any number of things, and you should first try to figure out where the noise is coming from.

It could be:
* front derailleur cage rubbing on chain.
* misaligned rear derailleur.
* dirty chain.
* worn cassette.
* etc.

So as you can understand, nobody can help you without any further idea the source of noise.
 

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Discussion Starter · #3 ·
good point

I should have been more clear. It is NOT the chain rubbing on the front derailleur cage. I believe it is more an issue with the chain somehow not being aligned correctly in the rear cassette....like when you have a chain line issue, etc.

It sounds / feels like the chain is not sitting correctly in the cassette adn therefore maybe rubbeing the side of the next gear in the cassette....maybe...????

I know it's not a matter of the front derailleur cage rubbing.

I have checked the rear derailleur and it appeared that the jockey wheels where not directly under one another so maybe the body is bent a little. I tried to straighten it and will ride and see what happens.

Matt
 

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classiquesklassieker
Joined
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3,113 Posts
bowler1 said:
I should have been more clear. It is NOT the chain rubbing on the front derailleur cage. I believe it is more an issue with the chain somehow not being aligned correctly in the rear cassette....like when you have a chain line issue, etc.

It sounds / feels like the chain is not sitting correctly in the cassette adn therefore maybe rubbeing the side of the next gear in the cassette....maybe...????

I know it's not a matter of the front derailleur cage rubbing.

I have checked the rear derailleur and it appeared that the jockey wheels where not directly under one another so maybe the body is bent a little. I tried to straighten it and will ride and see what happens.

Matt
You should check your rear derailleur hanger to see if it's bent. Then check to see if the cable and/or limit screws need adjusting.
 

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How old is the bike. I ask because it makes sense to eliminate chain wear (stretch) as a possibility before going crazy. Get a 12" ruler and stand the bike in a corner with the front wheel against the wall.

Tension the chain by pressing the pedal and line the 1/2" mark with the center of a pin, then look at the pin nearest the 11-1/2" mark. (I don't use the ends of the ruler because they're not reliably at the exact mark)

Since chains have 1/2" pitch every pin should line up exactly on a 1/2" mark, but wear at the pins allows the chain to pull apart a bit at each pin, - "stretch" - causing each link to be a bit beyond it's expected position. Over a distance this small error accumulates making stretch an easy and reliable to measure wear. If the pin at the 11-1/2" mark is beyond it by more than 1/16" the chain should be replaced. More than 1/8" beyond and it's likely the cassette overly worn too and that's what;s causing it to run rough.

If the chain isn't stretched anywhere near 1/16" consider trim (cable adjuster) and/or the high gear limit, though the limit only affects the outermost position.

That's for starters, after that, RD alignment worn idler pulleys, poor/no lube, etc.

BTW different causes make different sounds. Stretched chains make sort of a whirring or humming sound, trim and alignment sort of a clattering sound, and no lube a chirping or squeaky sound. After a while you can diagnose the problem by the nature of the sound alone.
 
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