BIKEPGH MESSAGE BOARD ARCHIVE

Worn chainrings most likely. Might be just one or two, might be all three. An experienced mechanic can take a look at the rings and tell you.

if you ride that bike a lot you should probably change all parts of the drivetrain at the same time.

worn things tend to wear together well, and when you introduce a new part into their worn world, things can go haywire.

I would agree take it into your local bike store.

The other possibility is that the new chain has too many links in it. New chains have a "genericc" number of links (at least the ones I* have do). If you wern't having a problem before than I woiuld have thought that the cassette & chainrings were okay(probably have some wear though).

If you weren't having a problem before

Not so... Once the chain wears appreciably, it wears the cogs faster. The smaller cogs will wear faster than the larger ones (unless you never use them, of course) because the chain pulls on fewer links and the angles are sharper. If you change the chain soon enough, you will extend the life of your cogs a bit. I'm just frustrated that I can't replace only the 15t cog on my cassette, since that's the one I wear out fastest.

It is possible that the chainring is worn, but it's hard to believe that would happen in only three years. Although, MTB chainrings are pretty small, so maybe.

Sight unseen, I'd go with iceman's guess that you didn't shorten the chain, and the derailleur can't take up the slack in the smallest combinations.

my first thought was "rear derailleur is out of alignment".

if it's off just a little bit, it will occasionally try to skip up or down and then realize its error and try to go back.

check it out, because it's the cheapest and easiest fix, and you don't want to replace your entire crank set when you could've just turned a barrel adjuster a half turn.

Oh, good point! It could be just out of adjustment, or the derailleur hanger could be bent, which would suck. Though it seems unlikely that would coincide with the change chain chain.

Thanks for all the replies. I don't think it's out of adjustment. I was hoping that was the case, but doesn't seem to be.

To those who suggested I take it to a local shop to be looked at, can you recommend a place? I've taken bikes to a couple local shops before and was not satisfied with their work. That's one of the reasons I try to fix things myself, but I'm a bit stumped on this and don't want to replace the front crankset and then find out that's not the problem either.

Steve K, at Iron City, who also posts here.

Pro Bike has some good mechanics but deal with the mechanics and not the sales people.

I'd be willing to bet some money it's the crank. If you haven't replaced a chain in three years everything is going to be pretty worn.

Ps you don't have to replace the crankset if the front is the problem, just the chainrings. I'm sure you and everyone know this, just keep seeing people saying crankset, not chainring.

Is it skipping across the cogs or ghost shifting?

also, a lot of lower end cranksets have riveted chainrings and the whole thing needs to be replaced. something to consider..

Take your chain off or just move it off the chainrings and check to see that your derailleur pulleys are spinning freely, they don't usually get much attention and they can gum up and cause problems.

+1 to icemanbb.

Some (all?) r. derailleurs have a tension spring on the pivot bolt that may need more tension.

I'd be a little surprised if it is the front chainrings causing the problem, I've worn chainrings down to deadly pointy little devil teeth and not had that particular problem.

also, a lot of lower end cranksets have riveted chainrings and the whole thing needs to be replaced. something to consider..

this is why i said "crank set" earlier. i was thinking of the worst case scenario to properly contrast the ease of a mere derailleur adjustment.

One other thing. You may just have one link that is too tight, so it sticks and doesn't bend properly. This is unlikely on a new chain, unless it's the first time someone has ever changed one. You can find this by running the chain backward on one of the smaller cogs. It will hop a little bit as it passes around and through the derailleur. Probably not what's going on here, as it doesn't fit the "anytime I stand up" mold, but the fix is easy: take your chain tool and loosen up the sticky rivet.

bending the chain in the wrong direction can loosen up stiff links too. Hold the chain in both hands, put your thumbs on the side of the chain link that isn't bending and bend the chain around your thumbs. Don't go crazy, just give it enough pressure to flex the chain a bit.