chain rub on front chainring

[madscot13]

How do i adjust to get rid of this? It is not on the derailleur it is on the chainring itself. I can't really say I've had troubles shifting but I'm not terribly sensitive to those things- or things in general.

[DebW]

Which front chairing/rear cog combinations do you get rubbing on? Small front-small rear there is often inevitable rubbing. Only thing to do is avoid those cross-over gears.

[madscot13]

It is middle chainring with the smallest rear cog. chainrub with the second smallest rear cog is not noticeable. i tried to increase the H limit screw but that only seems to make it rub in the back.

I should also say i have a triple.

[DebW]

There is no way to eliminate it. Just avoid that gear combination. That's actually somewhat unusual on a triple, but very common on a compact double. Depends on the difference in the chainrings and the bike geometry/chainline. Short chainstays make it more likely.

[madscot13]

thanks Deb. It is sort of strange because it is a new occurrence, or at least I think it is. I'm sure i would have noticed it before.

[OakLeaf]

Deb, is it a bad practice to use all ten cogs with the middle chainring if I'm not getting any noticeable rub?

[DebW]

Deb, is it a bad practice to use all ten cogs with the middle chainring if I'm not getting any noticeable rub?

No and yes. You don't have to strictly avoid that combination. But it still puts the chain at a considerable angle and you shouldn't use that combination a lot.

Mad, either that chain rub has always been there or it's appeared recently as your chain has aged and become more flexible, ie. the chain can now bend with a shorter radius as it comes off the chainrings and has to move sideways to meet the outer cog. You might stop by a bike shop and have them check your chain stretch. Or put a ruler next to your chain. 12 links should be 12 inches. If it's 12 1/8 inches your chain has stretched 1% and should be replaced.

[madscot13]

thanks Deb, this was on my list of things to check but I didn't have a way to measure it at home, or so I thought. (I'm trying to be more self- sufficient- or at least self sufficient with TE help- and so I am avoiding going to the bike shop unless I can't help it). The chain has stretched a small bit so that the 12" mark is a little after the beginning of the link about, yes, an eight of an inch off. I have an sram chain so I won't need anything special to take it out. i think I might need one to shorten a new chain though. doh!

I guess changing the chain will be a good way to get rid of that squeak I've been hearing too.

I am a little surprised that I need to change the chain after a year of use, though. when I was training for my century I would clean my bike once a week or about every 100 miles. and during the winter I would do it about so often because of the bad weather.

thank you for explaining how stretching the chain could also produce this problem. I should say for clarity sake, it is not a chain rub as if you were cross chaining, it is more of like a slap or a rattle. I can't really describe it any other way.

once again thanks.