Check the B-limit screw and chain length. Both could contribute to this occurring.
Chain falling to smaller cogs when backpedaling
Just obtained a 11-50t cassette, extended cage, and oversized pulleys from Garbaruk. Went from an X01 10-42t Sram. Both 11 speed. Kept the same single 32t Sram front chainring. Now, when I backpedal from the biggest cog, my chain drops to a smaller cog. I have seen this issue in various posts, but I am checking other's experience from the standpoint of going to any cluster with a bigger low gear cog - with any brand - and not necessarily Garbaruk. And more importantly, has anyone found a tweak that reduces or eliminates the problem. This might be my first post on Mtbr, and I appreciate your patience and help.
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If the spring tension from the derailleur is higher, a 'tighter' chain could explain it? Since you've got no guide pulley on the top, it's going to want to 'shift' even more to a straighter chainline when backpedaling because of the tighter chain? This is just a cost of 1x imo, and I just avoid backpedaling, especially in the climbing gears.
Definitely a cost of 1x. I've had this intermittently starting with 11spd. I was able to minimize it by taking a file to a few of the big cog teeth on a sunrace cassette, but it's really just the nature of the beast. My current Shimano doesn't do it on the same teeth every time, and I'm not going to take a file to all 45 teeth on my xtr cassette.
Lots of factors play into it. Chainline, chainstay length, and so on. But the biggest problem is that the cassette keeps getting wider and creating bigger deflections on the chain.
Lots of factors play into it. Chainline, chainstay length, and so on. But the biggest problem is that the cassette keeps getting wider and creating bigger deflections on the chain.
SRAM tried to remedy this issue with making the largest cog on their 12speed cassette narrow wide. It doesn't fix the issue 100% and introduced other issues, but it helped a bit.
I had a GX Eagle 30 x 10-52t and sold that bike for an XT 30 x 10-51t. Both would exhibit this "feature". Coming from a road bike I thought there was something wrong when it first happened but it seems to come with the territory. Although I almost never backpedal so I don't really notice it.
I agree, that with the 1x for mountain bikers who go to a big low gear cog, the chain line gets further away from ideal. I didn't have this problem with the 10-42 Sram 11 speed. Only when I put on the 11-50 11 speed, this week (same stack height as the Sram, just a bigger low gear cog). For reference, I put on the extended cage, cassette, and pulleys myself, then took my bike to a bike shop here in Culver City Ca., for them to size the chain, attach it, and tune the derailleur accordingly. I didn't want to end up with too short a chain. The KMC Unisex X11 chain came with 118 links; the shop took off two. So even with a "professional" bike shop doing the work, the result is the falling chain. So either its because of the oversized biggest cog creating a less than ideal chain line, or maybe the profile of the teeth on the Garbaruk is not optimal for pedaling backwards. Truthfully, only time I would backpedal is if on a rooted or rocky section on a steep incline, where I need to clear the obstacle by having both pedals on the same horizontal plane, and use small pedal inputs that do not see a crank revolution but resembles more like stabbing a brake pedal. Appears that there is no outright remedy, but that's okay. I needed the assurance that this is prevalent and is just the nature of the beast. Thanks for all the input, I appreciate the help.
I swapped my 10-50 SRAM Eagle cassette for a 10-52 Eagle and lost the ability to ratchet in the lowest gear.
I swapped to a -6mm offset chainring and fortunately it clears my chainstay and the chain (just) clears the tire with a 2.6 on the rear - and now the chain stays on during backpedals.
I swapped to a -6mm offset chainring and fortunately it clears my chainstay and the chain (just) clears the tire with a 2.6 on the rear - and now the chain stays on during backpedals.
yes dont pedal backJust obtained a 11-50t cassette, extended cage, and oversized pulleys from Garbaruk. Went from an X01 10-42t Sram. Both 11 speed. Kept the same single 32t Sram front chainring. Now, when I backpedal from the biggest cog, my chain drops to a smaller cog. I have seen this issue in various posts, but I am checking other's experience from the standpoint of going to any cluster with a bigger low gear cog - with any brand - and not necessarily Garbaruk. And more importantly, has anyone found a tweak that reduces or eliminates the problem. This might be my first post on Mtbr, and I appreciate your patience and help.
Why the quotes around professional? They probably used the correct length. As for why your chain does this, it's a combination of several factors all combined together. Sometimes addressing one of them will bring some improvement. Sometimes that's not necessarily enough.So even with a "professional" bike shop doing the work, the result is the falling chain. So either its because of the oversized biggest cog creating a less than ideal chain line, or maybe the profile of the teeth on the Garbaruk is not optimal for pedaling backwards.
To be fair, you're also using a pretty mixed up drivetrain, too. Good chance that's another one of your factors, and that's not the shop's fault. You're the one that bought the parts and had them install them.
The quotation marks are to contrast the difference between the professionalism of a bike shop, who readily repair and fix these things, and myself, who is an amateur. Also, it was to emphasize that even after taking it to a "professional" bike shop, the issue exists. My sentiment therefore, and I think others would conclude as well, that this must be an inherent and intermittent issue with the 1x. This was my thought process in using the quotation marks. But you thought that the quotation marks were used as a put down. It can be, but that's not the case, here. I hope you're clear.Why the quotes around professional? They probably used the correct length. As for why your chain does this, it's a combination of several factors all combined together. Sometimes addressing one of them will bring some improvement. Sometimes that's not necessarily enough.
To be fair, you're also using a pretty mixed up drivetrain, too. Good chance that's another one of your factors, and that's not the shop's fault. You're the one that bought the parts and had them install them.
By the way, anyone going to participate in the South Central Los Angeles CicLAvia, this coming Sunday? If you see a crew riding with full face helmets on black Lamere full suspension mountain bikes, give a shout-out, and we can stop and talk bikes.
I think it's incumbent on you to make it clear because you're not using quotes around the the word the way it's most broadly used. It's most widely used to do exactly what you say you're not doing here. To insult the actual professionals (typically their knowledge and/or skill). So by putting that word in quotes, the broader (American) English-speaking world will interpret that you are saying that the bike shop employees are poor excuses for professional bike mechanics. It's not that the quotation marks around a single word can be taken to mean what I thought. It's that they're usually used that way. And honestly, this is the first time I've seen anyone attempt to use quotes in the manner you've described here.The quotation marks are to contrast the difference between the professionalism of a bike shop, who readily repair and fix these things, and myself, who is an amateur. Also, it was to emphasize that even after taking it to a "professional" bike shop, the issue exists. My sentiment therefore, and I think others would conclude as well, that this must be an inherent and intermittent issue with the 1x. This was my thought process in using the quotation marks. But you thought that the quotation marks were used as a put down. It can be, but that's not the case, here. I hope you're clear.
But your conclusion about your drivetrain issue is essentially correct. Several factors related to big, wide, wide-range cassettes are related to the chain drop problem. There are some things you can do to improve it, but you probably can't make it go away entirely. I do expect at least a little bit of an ability to ratchet my pedals in my granny cog, so I have fairly high standards compared to most. But even I still have to tolerate some level of this if I want to run an 11 or 12spd drivetrain.
My XT equipped Top Fuel was doing the same from new, as was my GX Eagle equipped Pyga Hyrax. After making sure the b-tension, chain length and limit screws were all good I popped the bikes in the stand and back pedaled to see whether the chain was derailing at the same point. Turned out it was for both bikes. Had a look at where It was happening and saw the teeth were bent, so I straightened them up and the issue was solved. I can backpedal all day in 30/52 and 30/51 on both bikes
When I first got my Giant XTC Advanced SL 1 it had the same issue. back pedal and it would drop the chain into the smaller cog. I took it back to the LBS and they adjusted the position of the chainring closer to the frame. It lessened the dropping of the chain but it still did it. I changed the chain from a KMS X12 (stock) to a XTR chain and this all went away and my bike had a Deore XT drivetrain at that time. Now I have a Garbaruk cassette and chainring and all work fine.
My 11-46 shimano XT cassettes did this when new, as did the current 11-50 Sunrace one, but it pretty much stopped happening after the drivetrain bedded in. I can backpedal now on the Sunrace cassette after 6 months of use and the chain doesn't drop.
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