Amelio 

Good morning everyone, happy Thanksgiving 🦃 to those celebrating!

I just started getting some chain drop on my sram front derailleur, surprise surprise! The chain is falling off the small ring. I was winding down from a nice 23km ride on the small side street and it also shifted down to the small rain and I topped the rear derailleur to go up another couple rings chain fell off. A passerby had a huge grin on her face watching me put my chain back on, A bit embarrassing but whatever hahaha. Not as embarrassing as slowing down and getting my tire caught in a tar-filled rut beside curb, popping up out and up onto the sidewalk not being able to get my foot out of the pedals and crashing into a bush which kept me totally upright! That was the luckiest minicrash of my life! Felt like such a stupid boneheaded move. I just can’t think quickly enough to twist my feet and pull them up and out of the pedal clips. 😐

anyway!

I tried adjusting the lower limit screw which is the bottom screw and while testing, hanging vertically from the front wheel, the chain keep falling off but perhaps it’s the position of the bicycle? The mechanism is definitely not designed to operate vertically, if the gene requires gravity is pulling in the wrong direction.

I need to get out and give it a test ride.

any ideas folks? Am I in the right group? Is there a group for shifting sram front shifting issues?

p.s. someone told me SRAM can’t make a proper shifting front derailleur which is why they push 1x.

datlas 

I await input from SRAM experts, but consider a chain catcher? I use one on my bikes to prevent that rare but frustrating chain drop. The K-edge style works better than the dog-fang style fwiw.

DaveSSS 

Sram etap axs 12 speed is what I have and is different than etap 11, but I see the same type of alignment marks on the FD cage. 12 speed has a height window stamped inside the cage that's used to set the height to the tallest teeth on the big ring. The chain really needs to be off to setup the FD. A common problem is alignment the marks on the cage with the clamp bolt lightly tightened, then failing to notice that the FD has rotated slightly out of alignment when the clamp bolt is fully tightened. I have to set mine slightly crooked to start with so it ends up with the marks parallel to the big ring after tightening. I also take an accurate gap measurement between the derailleur cage and crankarm, before and after tightening.

I've setup my two bikes 8 times with 6 cranks and never had a chain drop. I first used Campy chorus 12 cranks, then shimano grx 46/30 and now grx 48/31.

Amelio 

thanks for all the great info Dave, really appreciate it. Mine is also SRAM

12 speed and I saw the side to side marks but didn’t realize there were height marks as well. The yaw marks don’t actually line up with the big ring, at least the back of the derailleur is a little off, I’ll have to fix that.

After my adjusting of lower limit screw last night, I took it out for a spin today with lots gear changes and couldn’t get it to drop chain, it seems pretty solid, but I’d like to adjust the FD height and yaw.

The groups you mentioned at the bottom are mostly Shimano and my experience with Shimano’s been great with no drops at all. I really hope this SRAM setup can tweaked to be similar.

chaadster

I have no drop problems with Force AXS FD, but it does require proper setup to function properly. Shocker, right? SRAM have setup instruction vids on YouTube, and my FD came with a tool for proper cage height placement.

DaveSSS 

One thing I should add is that the marks on the cage must be parallel to the big ring, but they won't be located directly over the big ring. It's the parallelism that's critical. I'm not fond of SRAM's limited 13T difference at the crank, so I use other cranks to get more range.

Amelio 

Oh that’s really interesting, you are so we passed me in an experience, thanks very much!

You’re using other cranks and it still shifts just fine? That’s great!

I bought the front derailleur alignment tool today, should make things a bit easier:

Amelio 

But it’s electronic, it should just do it all itself! 😂

thanks Chaadster I purchased that tool today.

DaveSSS 

I've never used the sram tool. Even with it, you should do an eyeball check for parallelism after tightening the clamp bolt. The tool won't stop the FD from rotating when the clamp bolt is tightened. I have to deliberately set the cage a little crooked, so it ends up parallel when tightly in place.

flx100

I just want to confirm this - i have the same experience. This parallel alignment is super important for proper front shifts, and yes, check again after tightening as it will have moved.
I also have the derallieur as low as it can possibly go without touching the chainrings.
In my experience these two things need to be adjusted very accurately, and the limits also need to be spot on. Not easy to get right.

JohnJ80

You should be good with the alignment tool but I'd also install a chain catcher at the same time (as long as you are fiddling with the FD position). The parallel alignment is exceptionally critical on eTap (at least it was on my 11 speed eTap). I just spent some time putting on an oval chain ring where it is even more critical, and it takes some patience and fiddling time. That said, both parallel and the height above the chainring matter and the SRAM ones have been touchier IMO than the Shimano ones.

J.