Hi, hoping someone has a tip. I have a 1x9 Advent setup with a narrow-wide chainring and I keep dropping the chain while shifting, esp. in bumpy conditions. I've adjusted the clutch tension so there's almost no forward movement of the rear derailleur. Any ideas besides using a chain keeper?

Thanks in advance.

You didn't specify which end of the cassette the chain was on when this occurs, whether it's dropping on upshifts, downshifts, or both, if your chain is trimmed to a proper length, or if you have modified the chain line by installing a different crank or bottom bracket. Go back and check and get back to us.

how worn out is the chain?
a noodley chain will derail easily....

Are things worn out? If things are happening on the chainring side do you have a good quality narrow wide chainring? If on the cassette end is the derailleur properly adjusted including limit screws and cable tension? Worn parts or maladjusted parts will certainly be more likely to come off more easily.

I solved this problem by putting on a 2X crankset on the front, along with a front derailleur.


What is wrong with using a chain keeper? I have one on another bike (1X11) and it is innocuous. It looks like a little plastic front derailleur that doesn't move. (I am assuming your chain is coming off the front.)

gearing options with a guide... a perfect solution!
i run 3x

Sorry, but I have to ask the obvious--do have the wider section of chain on the wider tooth and narrower part of chain on the narrow tooth of the narrow-wide chainring?

So far the only derailment problems I've had one 1x setups have been only in the rear, during backpedaling in the lowest gear / highest tension. So I'm interested to see what more troubleshooting reveals. Would definitely check all the normal things as listed above as well as derailleur hanger alignment and indexing adjustment

Not doing that would be a pretty good trick!

Thanks--middle of the cassette, and typically on upshifts. Chain length should be good as it is factory stock, and I've made no modifications.

Not very--just about two hundred miles on it at this point.

Thanks--it's on the chainring side and it's got a nice FSA narrow-wide ring. On the rear end everything's tuned pretty well, which is why this is a bit of a head-scratcher for me.

Nothing wrong with that at all--just don't want to spend the money if there's a simple adjustment I'm not thinking about. And do you have any recs for a reasonably priced one? The Paul ones are nice but quite spendy.

Thanks, obvious questions are good ones. Yes, the chain is where it's supposed to be--since I'm frequently putting the chain back on, I know that I couldn't get it to go the other way if I tried.

The sudden slackening of the taut span of the chain, caused by shifting to a smaller cog, can trigger a wave that can throw the chain off a chainring, especially in bumpy terrain. If there are no defects on the chainring or chain, everything points to insufficient chain tension. Find the shop manual for your rear derailleur and execute the derailleur manufacturer's instructions for chain length and b-screw tension, not the bike manufacturer's. Bike brands aren't infallible. For example, years ago, we had a line of mountain bikes from Marin that needed extracurricular work to make them shift right.

This is the one I got for my e-bike:

https://www.amazon.com/dp/B082KFBFS1...d_asin_title_1

For my wife's old mountain bike, I couldn't find a 1X chainset that was appropriate, so I got a 2X (replacing the original XT 3X) and that has worked great with the Advent 9-speed, even though it was supposed to be for 1X.

Paul components are very boutique and expensive. (They are of high quality, too.)

i think i see the problem now....
you can see it too....it says "advent" on it.

get the chain guide.

and check to verify that the chain is cut as short as is possible, without being TOO short.

Funny you should mention that--this is in fact a Marin. Will have a look at both chain length and b-screw tension. Thanks!

thanks!

Will do, thanks!

One suggestion I can make:Is it possible that you have too much friction in your free hub body. If you do, and you ease off pedalling, the top loop of the chain can go slack and a bump could throw it off the chainring. You can easily test this by removing your rear wheel and seeing if there is significant friction when you turn the cassette counter clockwise by hand

^ that is a good thing to check

And the culprit was.....the b-screw. It had about a third of the manufacturer's specified clearance. A few turns of the screw and a 20-mile bumpy ride later, no chain drops. I'll probably put a chain guide on just in case, but I'm cautiously optimistic for now. Thanks for all your tips and suggestions!