Chain N00b

[Gimpy]

So I need some advice about chains.    Before the Duc I have only had shaft driven bikes so chain maintenance is new to me.  I have been cleaning, lubing and checking my chain tension and it doesn't seem stretched out.  I have lots of room left on the axle adjustment.  Measuring the tension is several places doesn't show any tight or loose spots. There is no evidence of shark fins or missing teeth. It's a little past 12K miles so I am doing all the maintenance items before the weather gets good so I need to know if I need to add this to my list. I have put about 7000 miles on this bike, and have no idea of the maintenance history of the bike before that.

Do I need to change the chain simply because of miles? or is it changed when it stretches past a certain point?

I want to change out the front sprocket to a 14 tooth.  Should I change both the sprockets and the chain, or is just replacing the one sprocket OK?

If I do have to change both sprockets should I go up 2 teeth in the rear rather than down one tooth in the front?

Thanks in advance.

[DucHead]

So I need some advice about chains.    Before the Duc I have only had shaft driven bikes so chain maintenance is new to me.  I have been cleaning, lubing and checking my chain tension and it doesn't seem stretched out.  I have lots of room left on the axle adjustment.  Measuring the tension is several places doesn't show any tight or loose spots. There is no evidence of shark fins or missing teeth. It's a little past 12K miles so I am doing all the maintenance items before the weather gets good so I need to know if I need to add this to my list. I have put about 7000 miles on this bike, and have no idea of the maintenance history of the bike before that.

Do I need to change the chain simply because of miles? or is it changed when it stretches past a certain point?

I want to change out the front sprocket to a 14 tooth.  Should I change both the sprockets and the chain, or is just replacing the one sprocket OK?

If I do have to change both sprockets should I go up 2 teeth in the rear rather than down one tooth in the front?

Thanks in advance.

Sounds like you're doing all the right things, just keep an eye on it, and IMO if it is showing no signs that suggest the need to replace, then keep it.  The most miles I've gotten out of a chain is about 15000, but I've heard plenty of people who routinely get more with care.

Again, IMO (and experience) replace only those items which are worn.  If you put on a new 14 tooth, it's worth a few bucks to get a case saver.  California Cycleworks sells them as does Desmotimes.  If you go down one in the front, its like going up three in the rear, but the latter might require a chain with a link or two more.  I've had a 14-tooth front sprocket on my bike for well over 15000 miles without problems.

[Howie]

Agreed.  Chain life varies, but I got 22K out of my last chain including winter riding.

Besides what you already said, when you find you are adjusting the chain often,  can pull the chain away from the back of the rear sprocket and expose more than 1/2 a tooth, spot damaged O rings or constantly see fine brown rust coming from the rollers.

[ScottRNelson]

You also need to check for tight spots in the chain.  Measure the chain slack, then rotate the rear wheel about six teeth distance and check again.  Continue until you've checked the whole chain.  It's a good thing to do when you're cleaning or lubricating the chain.  If the chain slack differs by more than half an inch anywhere along it, time to be looking for a new chain.

I consider a 14-tooth front sprocket to be a quick fix for gearing issues.  Whenever I'm getting a new chain and sprockets, I always put a 15 on the front and get the rear size that I think will give me the optimal gearing.

[hypurone]

Do I need to change the chain simply because of miles? or is it changed when it stretches past a certain point?

I want to change out the front sprocket to a 14 tooth.  Should I change both the sprockets and the chain, or is just replacing the one sprocket OK?

If I do have to change both sprockets should I go up 2 teeth in the rear rather than down one tooth in the front?

I would always recommend changing both sprockets together with a new chain, though I have to say (and others will poo-poo it) that after going to a 14t front, my chain wear increased dramatically. It does make the links bend tighter on the chain....

I just went thru a 520 conversion primarily to save weight from a 525 14/43 setup. And to maintain close to the  same ratio (I had to go back to a 15t front, really long story but worth it- read CF wheels!  ) I needed to go up 3 teeth on the rear (actually was a teeny tiny bit short). So if ya don't wanna go to a 14t front, add 3 teeth to your rear sprocket:

EX: 14/43 ratio = 3.0714  15/46 ratio = 3.0666

[Gimpy]

At first I was checking everything looking for something to go wrong, cause I wanted the experience with changing out the chain.  Now I just spent $850 on a new suspension setup (so far) and I'm thinking I can have that experience later 

Since there are no tight spots, I've never had to tighten the tension, and it has lot more room to slide back the axle, I'm thinking I can save a few bucks at the moment. 

Although it might be nice to swap everything out just to keep it all at the same wear level.  Damn.  Coming from the cheapness of never having to do anything to shaft driven bike chains and sprockets are expensive.

At least the case saver is cheap.  I think I put that on the first month I bought the bike.  I was nervous about having a chain and I saw some nasty pics of broken cases.   

[Gimpy]

Would going up 3 teeth in the back to 41 require more lengths than the stock chain?   I'm toying with the idea of changing all three elements after looking at the amount of adjustment left.  There still is some but not as much as I thought. 

[ScottRNelson]

Would going up 3 teeth in the back to 41 require more lengths than the stock chain?   I'm toying with the idea of changing all three elements after looking at the amount of adjustment left.  There still is some but not as much as I thought. 

Each link is 5/8".  Adding one tooth to either sprocked moves the rear axle forward by very close to 1/4 of that distance, or 5/32".  You can look at how much axle adjustment room you have to see how many teeth you can add before the axle is hard against the front limit.