Help needed, shifting issue

[joy]

I have an S40, with a SRAM Force 22 Yaw front derailleur. I am in CT and ride mostly flat country roads and rail trails in Mass. and CT. I am usually in the big chain ring in front and 4 or 5 in the back. When I come to a crossing, I shift down to the small chain ring, then up shift once across. Most of the time it works smoothly, but every now and then, upon trying to up shift to the large ring, the chain falls off to the inside and I can’t get it back. When that happens, it usually falls behind the chain minder (?) and ends up jammed down there. Yesterday, I had to remove it to get the chain back on the ring. We have tried everything to fix this. Never happens in the shop, of course. Any ideas?

 

[cpml123]

Do you have 50-34 in front? That size appears to be the commonality in the shifting problem. I think the consensus is that FD has to be adjusted exactly right or change the big ring to 52 to resolve the issue permanently. I learned to shift mine very carefully, otherwise the chain will drop outside the big ring when shifting up. Very annoying.
Here is the thread on that topic.
https://cruzbike.com/forum/threads/the-compact-chainring-front-mech-issues-thread.12284/

 

[joy]

I have a 50/34. It shifts butter smooth 99.9 percent of the time.

 

[Mathew Fy]

I only have this problem when I’m in the 11 & 12 tooth cogs and up-shift to the 50 tooth chainring quickly. You could try adjusting the outward limiting screw a quarter turn to reduce drop-offs. This may,however, make up-shifting difficult when you’re in the largest cogs (when the chain is left of center)

 

[Bill K]

I have a similar issue except with 50/36 Qrings and DI2 derailleur. It sometimes over shifts (chain falls between the large chainring and the crank) or under shifts and stays in the small ring. Adjustment is very sensitive.

As a fallback if the chain is falling between the crank arm and the large chainring, you could install something like the "Rotor Chainring Chain Catcher Pins" to prevent the chain from getting jammed.

 

[joy]

The chain falls off to the inside,, between the small chainring and the bottom bracket. Sometimes I can catch it by shifting quickly back down, and it will come back up to the small chain ring. Other times lately, it has been going off and getting stuck below the chain minder arm (or whatever that arm is called) and the small chain ring. I then have to stop and loosen the arm to move it so I can pull the chain back up and over onto the small chain ring. Sounds like I’m going to have to live with it, as I’d hate to try more adjusting and make it worse.

 

[Jeremy S]

The chain falls off to the inside,, between the small chainring and the bottom bracket. Sometimes I can catch it by shifting quickly back down, and it will come back up to the small chain ring. Other times lately, it has been going off and getting stuck below the chain minder arm (or whatever that arm is called) and the small chain ring. I then have to stop and loosen the arm to move it so I can pull the chain back up and over onto the small chain ring. Sounds like I’m going to have to live with it, as I’d hate to try more adjusting and make it worse.

Usually the lower limit screw adjustment prevents this, but I’m sure you’ve tried tweaking that. I’m surprised this is happening while you’re shifting up, the derailleur is moving in the wrong direction, very confusing.

 

[cranky cyclist]

I have had this happen to me. Usually though I try tried to shift back to the smaller gear and then it came off both gears and lodged between the small chainring and the chain catcher. derailleur adjustments only cost about $10 to $15. You might want to take it to a pro. I did and it works great now.

 

[dtseng]

I cannot understand either why chain would fall inside during up-shift. I would guess that it has to do with that "yaw" stuff.

 

[Bill K]

If the chainstay bolts that clamp over the bottom bracket shell are loose it could cause poor/unpredictable shifting. It's unique to CB and mechanics may not know to look for it.

 

[super slim]

If the chainstay bolts that clamp over the bottom bracket shell are loose it could cause poor/unpredictable shifting. It's unique to CB and mechanics may not know to look for it.

That is EXACTLY what happened to me, EVEN with a Shimano derailleur!!
I had adjusted the boom length and forgotten to retighten the BB bracket clamps!!

 

[joy]

I have had this happen to me. Usually though I try tried to shift back to the smaller gear and then it came off both gears and lodged between the small chainring and the chain catcher. derailleur adjustments only cost about $10 to $15. You might want to take it to a pro. I did and it works great now.

Exactly! Then the chain catcher keeps me from being able to get the chain back on to the chain ring and I have to loosen it, move it, then retighten. I am reluctant to bring it anywhere, as it is fine most of the time. Thanks for the responses.