My chain is catching on the large front chain-ring sometimes instead of shifting to the small ring. It catches on the bottom teeth as shown.



What are some possibly reasons, cross chaining, dirt, bad teeth on ring, etc??? I noticed it happens while in a bigger cog in the back.
(Question)


Thanks,
Marty

PS, I use this as my chain lube but I'm open to changing it. Amazon.com: Dumonde Tech Lite Bicycle Chain Lubrication

What?

"6-O'clock refers the big hand on a clock pointing a the 6. (Front large ring, 6 o'clock position, it hangs/catches.)

He said "What?" because what you said makes no sense.

Do not shift the front when cross chaining. Better yet, don't cross chain(especially with a triple crank).

Might be chain suck.

Have you fitted a new chain recently ? How much use mileage has the big chainring had ? Might be time for a new one.

Some good info here
J LEVY | BikeTechArticles | Chain-Suck : Its causes and mechanisms, How to avoid, prevent, and remedy
Diary of a Mountain Biker

Also check there are no stiff links in your chain.

Chain lube will not make a differrence.

Brand new chain, not sure how well is was fitted?? I has someone else tell me that it might be chain suck, what ever that is. LOL I will look at the supplied info, thanks!!

If someone has a link on how to fit a chain correctly please provide and I will verify.

Thanks!!

After rereading your post it sounds like cross chaining. Don't use big rear sprockets with the big chain ring. You are forcing the chain to bend laterally whenever you cross chain and big sprocket to big chain ring forces the chain to bend the most as the distance between the two points at which the chain bends is the shortest.

You need to use the middle chainring and a smaller rear sprocket. It will give the same gearing and a straighter chain.

Using a triple exacerbates the problem as the big chain ring must be further out than if you were using a double chain ring setup.

EDIT: a new chain will also bend side to side less than an older worn one.

Trying to figure out what this means. To me, it seems like you're saying:

I'm cruising along in my middle ring and when I get to a hill I go to shift into the small ring but my chain wants to shift into the big ring instead.

If that's right, I guess the first thing I'd do is look to see if the big ring is straight.

Which cog are you in when you notice this?

No sorry, I'm really bad at explanations sheesh. I have a compact 2 ring so what happens happening is I'm going along in the big ring when I hit a hill so I shift to a bigger cog in the rear. Out of the 10 cogs I'm in like 7th of 10 cogs, 10th being the largest. Hope that helps.

I didn't think it was possible but your further explanations and pictures have only obfuscated the problem. Congratulations!

So... when you try to shift the front derailleur so that your chain moves from the large to the small chainring, the chain doesn't actually move, is that what you're saying?

I see the problem.

There is a big red curvy arrow on your big chainring. Remove the arrow and things should be better.

Use a better chain lube. If that doesn't fix it, use a better degreaser. If that doesn't fix it, try the mechanics forum. If you don't get the right answer there, try your LBS.

If all that seems like too much work, start at your LBS.

I can't imagine that chain lube has anything to do with it, plus Dumonde Tech is terrific stuff, IMO of course.

Trust an engineer to see the problem right off.

You probably need to readjust your derailleur.

I wonder if the chain is too short? Total guess...

There's some really great help here!! Thanks for these suggestions, it gives me a good place to start!!