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Discussion Starter · #1 ·
I have adjusted my limit screws on my rear derailleur and it seems to be indexing correctly, however, ONLY when I pedal backward and freewheel the chain skips to another cog. It happens mainly when I have it on a stand and I freewheel while putting lube on my chain. What would cause this to happen? I am not putting any pressure on the chain or derailleur when applying the lube. I have tried adjusting the barrel adjuster and the limit screws without much success. It seemed to work for a limited time but after about 5-6 rides it skips again. If this is happening, does it mean I have not adjusted it correctly? Any opinions would be appreciated.
 

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Trail Tire TV on blogger
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B screw set wrong..
very lightly out hanger
too much chain flex.
Crank's chain line too far out board

those are my first guesses without more info and being able to see it.

many will say the B screw won't cause this issue.. but it can, and is usually the first thing I look for when I hear this and 75% of the time it's the issue.
 

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Discussion Starter · #3 ·
I tried to adjust my b screw. I adjusted down from the bottom of the biggest rear cog and almost everywhere in between and nothing helped. I will look at my rear hanger next.
 

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I tried to adjust my b screw. I adjusted down from the bottom of the biggest rear cog and almost everywhere in between and nothing helped. I will look at my rear hanger next.
before you go on.. take the chain off.. and shift it to the largest ring on the cassette.. set it so the tooth of the jockey wheel is 6mm or so off the tooth of the cassette. you may have to pull the cage forward by hand but you need to see the teeth which is why you need the chain off... (this is for SRAM and SHIMANO 9 speed, 10 speed or 11 read the manual as the spec has changed depending on derailleur, manufacturer and cassette)

also what drive train is it? bike? derailleur? chain? how old? Old worn out chain and cassette will cause this..

have you gone to a none standard cassette? like the 9 speed 36 tooth? the range on these changes pitch and angle and the parallelograms were't really designed for them.. though the often do work they may cause issues.
 

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Discussion Starter · #5 ·
Stock 2012 Trek Superfly AL
Shimano Deore XT M780 rear derailleur
Shimano HG62-10 11-36, 10 speed
Shimano chain but don't know model of it

I haven't changed any of the drivetrain since I bought it towards the end of the year in 2012.
 

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Well if you ride pretty regular you most likely could use a new chain, if your riding a lot you may need a cassette also but I'd guess not unless you ride really long and often.. measure the chain ..straighten the hanger and properly set B screw and you should be good
 

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A bike can shift pretty good even if the adjusting barrel could use a couple of turns from what's ideal, this flaw can show itself more readily when pedaled backwards. Assuming the hanger is straight (square one), drivetrain is clean and lubed, and the cables are in good condition (preferably new) then cable tension is the next place I'd look. Try it in a gear near the middle of the cassette and dial the tension one way and the other until it is silent pedaling forward, and then then see if it backpedals OK. If you get that good and it's not consistent throughout the cassette then you have to delve back into the fore mentioned items. Don't concern yourself with the limits unless your checking the high or low cog.
 

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Take the derailleur and cassette off. Replace with single cog and no shifting problems :)...jk

When I have this problem, it's usually the b screw. If that doesn't solve it, I resort to the above.
 

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Discussion Starter · #11 ·
This is the best picture I can take but the bottom of the derailleur looks like its bent away from the tire. It should be square, or in line with the cog, correct?
 

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Trail Tire TV on blogger
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get the chain line from the front to the rear straight, then look.. right now you have it cross chaining and the chain will pull it out lightly so it may be normal. If the chain line is straight and it's still bent slightly out then straighten the hanger to align the derailleur.
 
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