Trouble with derailleur after removing 2 cogs
After removing the 11T and 13T from my cassette, adding 5.7mm behind the cassette and a 3.5mm spacer in front to allow the lockring to work, I'm having some derailleur problems.
1. I've got the low limit screw adjusted properly but when I try to drop back down to the highest gear (15T) it won't go because the low limit screw is so far out it is acting as the high limit screw as well.
The only solution I've come up with for this is to run the low limit so the chain could jump over the cassette but I set the derailleur tension with the shifter in 3rd so 9th is at the lowest gear. In theory the chain shouldn't jump over and in the stand it doesn't jump but it would suck to go ride this and have it jumping over all the time. Or I can set up the low limit screw correctly and have 6 rear gears. At least it won't mess up any spokes when it jumps over
2. The derailleur basically meets the 34T which makes it hard to shift into that gear. I've tried adjusting the B screw all the way (both ways) and neither is any help.
Speedways suggestion was remove the 34T and re-install the 13T. So I would still have 7 gears just not the 7 I want.
I'm sure some of you guys (or gals) have run into these issues when removing cogs and spacing the cassette so what did you do? Any help is appreciated
for?2, a longer chain might help to "relax" the RD a bit and allow it to shift over instead of into the 34. A smaller jump between the two highest cogs might help too, maybe try either a 32 low gear or else a slightly larger cog in 2nd position.
Note that if you are running fewer cogs, the cassette body of an old 7-speed setup is a bit narrower, will not require as much spacing and you can re-space the axel to move hub flanges over so there is not so much empty space between low cog and spokes.
Hmmm. I haven't gotten there just yet, but you might try putting a washer under the derailer pivot - moving the whole derailer out from the frame. It might not take a lot to get the limit screw to clear. Looking at one I've got laying around, there's a thread relief in the bolt - so you wouldn't even lose any thread engagement.
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Might help to know what kind of derailleur it is as well. Some work better than others with spaced-out cassettes.
What are you trying to accomplish? 7 speeds? What about just leaving the existing cassette on and using your limit screws to get there. Shimano or Sram? Would a road type closer range cassette work? One ring or two up front? If you are running a shimano hub, what about a shorter freehub? 7 speed cassette and a thumbshifter? Make a custom cassette. Some of them you can drill out the rivets and then make a cassette range of your choice, using the spacers and then the lockring to hold it all together.
Change the length of your limit screws? sorry, way over caffinated today.
Could you post a few good close ups of what is hitting what? I picture adding some material to the part of the derailer that the screw is supposed to touch so the screw does not have to be screwed in as far. Then the screw wont hit the area its not supposed to because it wont be scewed in as far. Maybe JB Weld a small peice of metal. Oh damn did I just say JB Weld? Otherwise just dont use the limiter and dont overshift. Good luck
I think Wadester's solution will end up being the correct one. You could even cut a slot in one side of the washer, then bend the rsulting tab over so that it sits on the B screw seat on the der. hanger, giving you some extra adjustment there as well. Simple, should be effective. I see no downside?
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I've had this happen to me with both 6 and 7 speed drivetrains (albeit it is not on a fat bike with a lot more tire). I do not tension the shifter in any particular gear as Sram's indexing is at the shifter itself. What I have done in separate instances and cog configurations is lengthen the chain, move from a short to medium cage or move from a medium to long cage, use a longer B-screw and physically modify the rear derailleur by creating a new limit 'perch'. A small tapped hole in the derailleur's body holds that L-shaped "chip" in place. I did not use a mill or anything to make this-it was before I had my shop up and running:
I've found that if the derailleur's pulley hits/interferes with the cog, it may be a simple adjustment with longer limit screw and tweaking where the cogset is on the rear hubs cassette body. Again-that may create some interference with the tire if that is your reason for modifying the drivetrain.
This can be solved by taking a Dremel tool to the edge of the pivot the lower limit screw contacts and relieving just enough material for it to clear. I've got a customer running BFL/90's and will probably do it next week. All the Sram der's have this issue. Shimano XT771 derailleurs do not, but I believe all the Shadow types do.
Using a longer limit screw will not solve the problem.
A know issue with SRAM RDs
Originally Posted by GTR2ebike
You might try adding a spacer between the derailleur and the hanger to move it out. This will also reduce cog/pulley interference.
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had the same type of issues.
add 1 link to the chain. made it work for me
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