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Why is my chain dropping???

3K views 16 replies 13 participants last post by  fahza29er 
#1 ·
I recently switchted from a 26er to a 29er and moved my XT groupset over(40/28 front and 11-36 rear). I kept the Sram FD that the 29er came with because it needs a direct mount FD.

My chain keeps droppin off the big ring on the outside. (NOT during shifting). It usually happens after I coast over a rough section and then try to pedal again. Another example is getting on top of a large rock (1 - 2 ft tall) at the base of a climb then standing to grind up the climb and have the chain drop.

I took it to a shop who said the FD cable tension was loose. That didn't fix it. Took it to another shop who said the chain was damanged and replaced it. That didn't fix it. I decided to purchase an XT FD since I never had this issue when I had an XT FD on the 26er. That didn't fix it.

Has anyone had this happen before? Does anyone have any possible solutions?
 
#5 ·
Chain is about 3 weeks old. The crank is XT785 with Shimano Pressfit BB.

When in the big ring the RD cage is pointing straight down or slightly forward depending on the gear in the back. In the little ring it is folded back.

I tried riding some in the little ring only yesterday and could not get the chain to drop. I wonder if the RD cage kicks forward when I'm going over a rough section and jumps the chain off the ring. Sometimes I can ride the chain back up, but often it is totally dropped.

I feel like I can keep it on if I concentrate on keeping some forward pressure on the pedals, but that also affects the way I ride.
 
#11 ·
View attachment 793609

Even better SRAM x9 type 2 no lever to engage like the shimano. Zero chain slap no chain drops shifts smooth
Nice looking RD. What do you have to dis-engage to remove your wheel? That clutch switch is for removing the wheel. I have not seen the X9 model but it looks nice. I got a great price on the XT, SLX was not ever making it to my ride but the XTR looked very nice. $225 for the XTR did not look nice. On line my XT is about $125, so my LBS matched it and it is one of the best investments I have made yet.

Mark
 
#12 ·
I had a brief problem with the chain dropping of the outside on a past bike. Reading the derailleur instructions carefully and setting it up exactly as instructed fixed it. Also making sure the chain isn't unnecessarily long will stop any sloppy bouncing around. The new generation derailleurs with the clutch will be an upgrade on each bike as they wear out.
 
#17 ·
Would it falling off under heavy load like a steep hill climb do the same thing? I went 1x9 and the chain falls off to the outside under heavy load, I can blast through ruff stuff ok but when climbing is when it pops off. I put a bash guard on and will see if that stops it. Can't hurt it at least it will protect the ring from rocks and fallen trees I go over. Its on my FS, my HT is setup the same way and dosent suffer from this, I was kinda stumped when it popped off on the climb. Raceface cranks and chainrings on both bikes.
 
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